[Amel Yacht Owners] Modified SM Prop Shaft Seal Bush


Bill & Judy Rouse <yahoogroups@...>
 

Ian, All, and especially newbies;

Most of you know that I have been and will always be the person in this group that warns everyone about changing an Amel design. It is nothing personal. I love all things Amel and I take it as my responsibility; so, because of that responsibility, I will offer the other side of CRUSADER's report and recommendation...nothing personal, but I am the self-appointed protector of all things Amel, and will always be the one to point out the RISK vs the REWARD in changing an Amel design.

<<<>>>
I am certainly no expert, but I believe that stainless steel comes in at least 5 types and also different hardnesses; and the Nitrile Buna-N seals are made in different hardnesses. Although I personally do not need the answer to the following questions, I believe anyone attempting to follow your recommendation should know: What type of stainless steel and hardness you used? What was the hardness of the seals? What were the engine hours between servicing?

I would guess that to obtain different results than the Amel-proven system, you have to either scientifically solve the wear issue to achieve a different balance between wear of the seal and wear of the bushing, or use a trial and error method. I assume that your method was trial and error, which resulted in changing the balance of wear between the wear bushing and the wear on the lips of the seals; which extended your haulout interval - your goal. 

We must remember that there will be wear between the lips of the seal and the wear bushing on the C-Drive. It is obvious to anyone who has serviced an Amel C-Drive that with the current Amel design the wear bushing appears to wear more than the seal lips. 

I would assume that one could scientifically change the balance to increase the interval of haulouts. However, it makes sense to me that unless a scientific approach is used, we would be playing Russian roulette with a very expensive part of our boat.

Don't take what I am saying as criticism. I am happy that you achieved your goal. My goal was to haul out every 2 years for more reasons than C-Drive maintenance.

I would urge all readers of this message to stick with proven Amel supplied parts and procedures, rather than changing something that you do not completely understand. I do not have the metallurgical and mechanical engineering expertise to develop a better system than Amel's wear bushing and seals, nor do I believe any of us have that knowledge. 

And, I will take this a step further: Many of the Amel systems that I have been exposed to, obviously take into consideration the required maintenance and the level of experience and knowledge of the person performing the job. When I managed new product development, I used the term "child proof." When I asked my staff if the new product was "child proof," they knew that I was asking if it would pass the test of the most ignorant user. I never met Henri Amel, but from my experience with his boats, I believe he also used my term, or one similar.

Until recently, I had no idea that the Nitrile Buna-N seals are available in a hardness range from 40-90, and I do not know the hardness of the Nitrile Buna-N lip seals that Amel uses. We all know that bronze, brass, and Naval brass are available in different hardnesses. I suspect that none of us know the hardness of the wear bushing that Amel uses, nor do we know the percent of copper, tin, and zinc . Without this information, I believe that changing the balance of wear between the bushing and the seal should not be attempted, unless you understand the huge risk for what, I believe, is very little reward.

Ian, it is very good to have you return to this forum. I have missed you and your posts. Probably none of us have more miles in a Super Maramu than you have.

​Best,​

CW Bill Rouse
Admiral, Texas Navy
Commander Emeritus
Amel School www.amelschool.com
720 Winnie St
Galveston Island, TX 77550



VLADIMIR SONSEV
 

Hardness of stainless steel 316 does not vary tangible. Bushing from stainless 316 will  definitely last longer, but the bushing will cost much more. 316 steel is expensive and hard to machin. But it is very good corrosion resistant material, good for salt water. If people are interested I can find mashin shop that can make them. We have to order 100 bushings or more. Otherwise setup cost is too much.

Vladimir Sonsev
SM 345
"LIFE IS GOOD"


On Aug 7, 2017 10:57 AM, "'Bill & Judy Rouse' yahoogroups@... [amelyachtowners]" <amelyachtowners@...> wrote:
 

Ian, All, and especially newbies;

Most of you know that I have been and will always be the person in this group that warns everyone about changing an Amel design. It is nothing personal. I love all things Amel and I take it as my responsibility; so, because of that responsibility, I will offer the other side of CRUSADER's report and recommendation...nothing personal, but I am the self-appointed protector of all things Amel, and will always be the one to point out the RISK vs the REWARD in changing an Amel design.

<<<>>>
I am certainly no expert, but I believe that stainless steel comes in at least 5 types and also different hardnesses; and the Nitrile Buna-N seals are made in different hardnesses. Although I personally do not need the answer to the following questions, I believe anyone attempting to follow your recommendation should know: What type of stainless steel and hardness you used? What was the hardness of the seals? What were the engine hours between servicing?

I would guess that to obtain different results than the Amel-proven system, you have to either scientifically solve the wear issue to achieve a different balance between wear of the seal and wear of the bushing, or use a trial and error method. I assume that your method was trial and error, which resulted in changing the balance of wear between the wear bushing and the wear on the lips of the seals; which extended your haulout interval - your goal. 

We must remember that there will be wear between the lips of the seal and the wear bushing on the C-Drive. It is obvious to anyone who has serviced an Amel C-Drive that with the current Amel design the wear bushing appears to wear more than the seal lips. 

I would assume that one could scientifically change the balance to increase the interval of haulouts. However, it makes sense to me that unless a scientific approach is used, we would be playing Russian roulette with a very expensive part of our boat.

Don't take what I am saying as criticism. I am happy that you achieved your goal. My goal was to haul out every 2 years for more reasons than C-Drive maintenance.

I would urge all readers of this message to stick with proven Amel supplied parts and procedures, rather than changing something that you do not completely understand. I do not have the metallurgical and mechanical engineering expertise to develop a better system than Amel's wear bushing and seals, nor do I believe any of us have that knowledge. 

And, I will take this a step further: Many of the Amel systems that I have been exposed to, obviously take into consideration the required maintenance and the level of experience and knowledge of the person performing the job. When I managed new product development, I used the term "child proof." When I asked my staff if the new product was "child proof," they knew that I was asking if it would pass the test of the most ignorant user. I never met Henri Amel, but from my experience with his boats, I believe he also used my term, or one similar.

Until recently, I had no idea that the Nitrile Buna-N seals are available in a hardness range from 40-90, and I do not know the hardness of the Nitrile Buna-N lip seals that Amel uses. We all know that bronze, brass, and Naval brass are available in different hardnesses. I suspect that none of us know the hardness of the wear bushing that Amel uses, nor do we know the percent of copper, tin, and zinc . Without this information, I believe that changing the balance of wear between the bushing and the seal should not be attempted, unless you understand the huge risk for what, I believe, is very little reward.

Ian, it is very good to have you return to this forum. I have missed you and your posts. Probably none of us have more miles in a Super Maramu than you have.

​Best,​

CW Bill Rouse
Admiral, Texas Navy
Commander Emeritus
Amel School www.amelschool.com
720 Winnie St
Galveston Island, TX 77550



Craig Briggs
 

Some time ago I asked SKF's engineering about this. Here's their reply to me:
"Craig, 
My educated guess is that the seals are not an issue in this application. The problem is with the Bronze bushing that is being used as a sealing surface. Bronze is generally quite soft and might not have the required hardness of Rockwell C 30 or higher. You have a few options to solve this issue:
• You can put SKF speedi-sleeve gold on the shaft (P/N 99830). You will probably have to install multiple sleeves as you have 3 seals next to each other.
• You can replace the bronze bushing with a hardened wear sleeve for better abrasion resistance. We can offer you a custom wear sleeve if needed.
• You can plate your bushing with a harder material (Chrome, ceramic, etc) to make it wear resistant.
Essentially, the harder the shaft is, the less grooving it will see. I also suggest you to make sure that you grease pack the area between the seals to make sure that the seals not in contact with the oil are well lubricated. A lack of lubrication can cause the seal and surface to wear quicker. Finally I would arrange the seals with 2 facing the water and one facing the oil as long as there is no pressure difference. 
Best regards, Jaydeep Laljani, Application Engineer, SKF USA

I wrote back and said:
"Many thanks for your analysis. Frankly, I have wondered why the manufacturer used Bronze in the first place and not stainless - they actually call it a "wearing-out bushing" (but then they do charge a lot for replacements :-). 
Next month I'm returning to the boat, which is in Turkey, and I can easily have a local shop turn a new bushing in 316 Stainless (the same material as the shaft and propeller, so no electrolysis issues.) I think that would solve the problem without going to sleeves or plating. 
As for the orientation of the seals, I like your suggestion of two facing the water and will do that the next time I change the seals. After all, we're really trying to keep the water out more than keeping the oil in. And, yes, indeed, I always pack the seals with a good water-proof grease and that helps, I'm sure. "

Jaydeep replied with:
"I think you might not get as much life as you want with 316 SS as it is still not up to the required hardness. If you want to go Stainless I recommend 17-4 Stainless steel which is harder. If you are going with the 316 SS I would recommend you to passivate it to improve corrosion resistance. " 

Hope that's helpful.
Cheers, Craig Briggs, SN#68 Sangaris


---In amelyachtowners@..., <sonsev52@...> wrote :

Hardness of stainless steel 316 does not vary tangible. Bushing from stainless 316 will  definitely last longer, but the bushing will cost much more. 316 steel is expensive and hard to machin. But it is very good corrosion resistant material, good for salt water. If people are interested I can find mashin shop that can make them. We have to order 100 bushings or more. Otherwise setup cost is too much.

Vladimir Sonsev
SM 345
"LIFE IS GOOD"


On Aug 7, 2017 10:57 AM, "'Bill & Judy Rouse' yahoogroups@... [amelyachtowners]" <amelyachtowners@...> wrote:
 

Ian, All, and especially newbies;

....
<<<<Here Goes>>>>
I am certainly no expert, but I believe that stainless steel comes in at least 5 types and also different hardnesses; and the Nitrile Buna-N seals are made in different hardnesses. Although I personally do not need the answer to the following questions, I believe anyone attempting to follow your recommendation should know: What type of stainless steel and hardness you used? What was the hardness of the seals? What were the engine hours between servicing?

I would guess that to obtain different results than the Amel-proven system, you have to either scientifically solve the wear issue to achieve a different balance between wear of the seal and wear of the bushing, or use a trial and error method. I assume that your method was trial and error, which resulted in changing the balance of wear between the wear bushing and the wear on the lips of the seals; which extended your haulout interval - your goal. 

We must remember that there will be wear between the lips of the seal and the wear bushing on the C-Drive. It is obvious to anyone who has serviced an Amel C-Drive that with the current Amel design the wear bushing appears to wear more than the seal lips. 

I would assume that one could scientifically change the balance to increase the interval of haulouts. However, it makes sense to me that unless a scientific approach is used, we would be playing Russian roulette with a very expensive part of our boat.

Don't take what I am saying as criticism. I am happy that you achieved your goal. My goal was to haul out every 2 years for more reasons than C-Drive maintenance.

I would urge all readers of this message to stick with proven Amel supplied parts and procedures, rather than changing something that you do not completely understand. I do not have the metallurgical and mechanical engineering expertise to develop a better system than Amel's wear bushing and seals, nor do I believe any of us have that knowledge. 

....
Until recently, I had no idea that the Nitrile Buna-N seals are available in a hardness range from 40-90, and I do not know the hardness of the Nitrile Buna-N lip seals that Amel uses. We all know that bronze, brass, and Naval brass are available in different hardnesses. I suspect that none of us know the hardness of the wear bushing that Amel uses, nor do we know the percent of copper, tin, and zinc . Without this information, I believe that changing the balance of wear between the bushing and the seal should not be attempted, unless you understand the huge risk for what, I believe, is very little reward.

Ian, it is very good to have you return to this forum. I have missed you and your posts. Probably none of us have more miles in a Super Maramu than you have.

​Best,​
Bill Rouse


 


Bill & Judy Rouse <yahoogroups@...>
 

Craig,

That is good information, but, you know me....self-proclaimed protector of Amel systems!

Please read my summary of why I believe in Amel's C-Drive design and service procedure:
The C-Drive will accommodate three seals and it is possible to orient two of the seals to either double the seal-capacity to keep oil IN, or keep water OUT. Which is more important? Seals fail and seals wear...and some owners and operators wait until failure before replacing. 

I firmly believe that Amel is correct, and I think that your engineer is mostly correct. The question is this: Which one of the above two choices is Low Risk? The C-Drive is expensive to replace. The C-Drive requires lubrication to keep it from failing. I prefer to ensure that oil stays in the C-Drive, more than I want to ensure that water stays out. My reason is because if oil leaks out, you may not know it until the damage is done...Conversely, if water leaks in, the oil will still have lubricating ability and you will see the evidence of the presence of oil in the reservoir. 

Additionally, I have personally serviced the C-Drive 6 times. I have audited, supervised, and taught C-Drive service another 12 times. I can assure everyone that if you get water egress, you have not followed the procedures, you have not serviced the C-Drive every 800 hours/2 years, or something like monofilament fishing line has ruined the seals.

One more thing about what the engineer wrote: He seems to ignore the fact that the harder the metal, the more that the Nitrile Buna-N seals will wear. Is it possible that Henri Amel knew that if the owner did not see wear-grooves, the owner would ignore the servicing intervals? I personally like to believe that this is part of the explanation because I believe he was a genius...but, you know me....self-proclaimed protector of Amel systems!

CW Bill Rouse
Admiral, Texas Navy
Commander Emeritus
Amel School www.amelschool.com
720 Winnie St
Galveston Island, TX 77550
+1(832) 380-4970




On Tue, Aug 8, 2017 at 10:00 AM, sangaris@... [amelyachtowners] <amelyachtowners@...> wrote:
 

Some time ago I asked SKF's engineering about this. Here's their reply to me:
"Craig, 
My educated guess is that the seals are not an issue in this application. The problem is with the Bronze bushing that is being used as a sealing surface. Bronze is generally quite soft and might not have the required hardness of Rockwell C 30 or higher. You have a few options to solve this issue:
• You can put SKF speedi-sleeve gold on the shaft (P/N 99830). You will probably have to install multiple sleeves as you have 3 seals next to each other.
• You can replace the bronze bushing with a hardened wear sleeve for better abrasion resistance. We can offer you a custom wear sleeve if needed.
• You can plate your bushing with a harder material (Chrome, ceramic, etc) to make it wear resistant.
Essentially, the harder the shaft is, the less grooving it will see. I also suggest you to make sure that you grease pack the area between the seals to make sure that the seals not in contact with the oil are well lubricated. A lack of lubrication can cause the seal and surface to wear quicker. Finally I would arrange the seals with 2 facing the water and one facing the oil as long as there is no pressure difference. 
Best regards, Jaydeep Laljani, Application Engineer, SKF USA

I wrote back and said:
"Many thanks for your analysis. Frankly, I have wondered why the manufacturer used Bronze in the first place and not stainless - they actually call it a "wearing-out bushing" (but then they do charge a lot for replacements :-). 
Next month I'm returning to the boat, which is in Turkey, and I can easily have a local shop turn a new bushing in 316 Stainless (the same material as the shaft and propeller, so no electrolysis issues.) I think that would solve the problem without going to sleeves or plating. 
As for the orientation of the seals, I like your suggestion of two facing the water and will do that the next time I change the seals. After all, we're really trying to keep the water out more than keeping the oil in. And, yes, indeed, I always pack the seals with a good water-proof grease and that helps, I'm sure. "

Jaydeep replied with:

"I think you might not get as much life as you want with 316 SS as it is still not up to the required hardness. If you want to go Stainless I recommend 17-4 Stainless steel which is harder. If you are going with the 316 SS I would recommend you to passivate it to improve corrosion resistance. " 

Hope that's helpful.
Cheers, Craig Briggs, SN#68 Sangaris


---In amelyachtowners@yahoogroups.com, wrote :

Hardness of stainless steel 316 does not vary tangible. Bushing from stainless 316 will  definitely last longer, but the bushing will cost much more. 316 steel is expensive and hard to machin. But it is very good corrosion resistant material, good for salt water. If people are interested I can find mashin shop that can make them. We have to order 100 bushings or more. Otherwise setup cost is too much.

Vladimir Sonsev
SM 345
"LIFE IS GOOD"


On Aug 7, 2017 10:57 AM, "'Bill & Judy Rouse' yahoogroups@... [amelyachtowners]" <amelyachtowners@yahoogroups.com> wrote:
 

Ian, All, and especially newbies;

....
<<<<Here Goes>>>>
I am certainly no expert, but I believe that stainless steel comes in at least 5 types and also different hardnesses; and the Nitrile Buna-N seals are made in different hardnesses. Although I personally do not need the answer to the following questions, I believe anyone attempting to follow your recommendation should know: What type of stainless steel and hardness you used? What was the hardness of the seals? What were the engine hours between servicing?

I would guess that to obtain different results than the Amel-proven system, you have to either scientifically solve the wear issue to achieve a different balance between wear of the seal and wear of the bushing, or use a trial and error method. I assume that your method was trial and error, which resulted in changing the balance of wear between the wear bushing and the wear on the lips of the seals; which extended your haulout interval - your goal. 

We must remember that there will be wear between the lips of the seal and the wear bushing on the C-Drive. It is obvious to anyone who has serviced an Amel C-Drive that with the current Amel design the wear bushing appears to wear more than the seal lips. 

I would assume that one could scientifically change the balance to increase the interval of haulouts. However, it makes sense to me that unless a scientific approach is used, we would be playing Russian roulette with a very expensive part of our boat.

Don't take what I am saying as criticism. I am happy that you achieved your goal. My goal was to haul out every 2 years for more reasons than C-Drive maintenance.

I would urge all readers of this message to stick with proven Amel supplied parts and procedures, rather than changing something that you do not completely understand. I do not have the metallurgical and mechanical engineering expertise to develop a better system than Amel's wear bushing and seals, nor do I believe any of us have that knowledge. 

....
Until recently, I had no idea that the Nitrile Buna-N seals are available in a hardness range from 40-90, and I do not know the hardness of the Nitrile Buna-N lip seals that Amel uses. We all know that bronze, brass, and Naval brass are available in different hardnesses. I suspect that none of us know the hardness of the wear bushing that Amel uses, nor do we know the percent of copper, tin, and zinc . Without this information, I believe that changing the balance of wear between the bushing and the seal should not be attempted, unless you understand the huge risk for what, I believe, is very little reward.

Ian, it is very good to have you return to this forum. I have missed you and your posts. Probably none of us have more miles in a Super Maramu than you have.

​Best,​
Bill Rouse


 



rossirossix4
 

I think someone else posted that Amel had been experimenting with stainless WOBs but had not had enough time yet to evaluate them.

I've made a couple of posts on the experimental stainless WOB that Amel Iinadvertantly?) sent me. You can search for the posts including responses.  I finally put the WOB on about a year ago in Marmaris, Turkey (August, 2016) and will probably run it until I detect water in the reservoir. 

These are excerpts from 2 previous postings I made on this.  THE PICS ARE  A WOB AS RECEIVED FROM AMEL!

In March, 2014 I ordered and received FROM AMEL a bronze wearing out 
bearing that had a sort of Speedi-Seal stainless/inox facing on the 
surface that the seals go over. I have posted detailed pics at Dropbox 
https://www.dropbox.com/sc/1tompsdjss3rr0r/AACGUoVzzawY5RnlyKpnjwRga

LATER
Mystery solved!  I just got off the phone with Maud (ordering new parts including an additional spare for my spare prop WOB (I admit it, like lots of us I carry 2 spares of certain items).  

I asked her about the unusual WOB that I had received more than a year ago and described it (bronze with stainless or chromed steel face).  She explained to me that it was a "test" from Amel to see if it would prolong the life of the part. She said that several were sent out for this purpose and asked me how it was doing.  I have not installed it but promised I would report back.  Here, again are pics of the part   Amel Test WOB (4 photos)    Bob Rossi SM 429 KAIMI

Like many of us I ordered the WOB after I installed one and then waited 2 years... I finally installed the Amel stainless WOB a year ago in Marmaris around 8/2016.  I have not heard of another owner receiving the test WOB but there was a posting regarding Amels testing of these with a note that not enough time had elapsed to reach a conclusion.


Ian Shepherd
 

Bill,

I believe that you are over complicating the issue. As far as  I remember the seals were from a local seal shop in Larnaca. I have no idea of the hardness but I can check when I get there next week as I bought more than I have used.

As far as the stainless is concerned, just plain old 316 is all I know. As Heinrich is no longer with us, I cannot find out, but maybe someone can test the bush which I still have.

The thing is Bill is that you are advocating people remain with a situation that we all know lets us down unexpectedly and often at an awkward time. You say you worry about protecting an expensive system yet you encourage owners to suffer sea water mixing with the lubricating oil. When this happens not everyone is in a position to haul out immediately. More damage may  be done if this happens

The benefits of what I have proven are:

The bush does not wear at anything like the rate of a bronze one.

As a result, it is now highly unlikely that the oil will be contaminated between say three year haul outs.

There is no electrolysis problem with stainless on stainless. at least not if lubricated with an anti corrosion grease such as Corrosion Block.

The fact that Amel are experimenting with a stainless surface indicates that this is the way to go. I am so glad that Amel have latched onto the idea, as they have with my idea of using sealed bearings in the bow thruster. Maybe they will look at a stainless sleeve on the bow thruster shaft too. It works!

You can protect the past all you want Bill, but my goal is to reduce nuisance servicing to the minimum so that I can enjoy sailing the boat.

Sometimes it pays to think outside the box.

Not sure about the mileage accolade. 48,273 as I speak almost all single handed. But then on an Amel that's easy!

Kindest regards to you and Judy

Ian Shepherd SM2K 41 Crusader (2003) Kasteloriso Island Greece


On 07/08/2017 14:48, 'Bill & Judy Rouse' yahoogroups@... [amelyachtowners] wrote:
 
Ian, All, and especially newbies;

Most of you know that I have been and will always be the person in this group that warns everyone about changing an Amel design. It is nothing personal. I love all things Amel and I take it as my responsibility; so, because of that responsibility, I will offer the other side of CRUSADER's report and recommendation...nothing personal, but I am the self-appointed protector of all things Amel, and will always be the one to point out the RISK vs the REWARD in changing an Amel design.

<<<>>>
I am certainly no expert, but I believe that stainless steel comes in at least 5 types and also different hardnesses; and the Nitrile Buna-N seals are made in different hardnesses. Although I personally do not need the answer to the following questions, I believe anyone attempting to follow your recommendation should know: What type of stainless steel and hardness you used? What was the hardness of the seals? What were the engine hours between servicing?

I would guess that to obtain different results than the Amel-proven system, you have to either scientifically solve the wear issue to achieve a different balance between wear of the seal and wear of the bushing, or use a trial and error method. I assume that your method was trial and error, which resulted in changing the balance of wear between the wear bushing and the wear on the lips of the seals; which extended your haulout interval - your goal. 

We must remember that there will be wear between the lips of the seal and the wear bushing on the C-Drive. It is obvious to anyone who has serviced an Amel C-Drive that with the current Amel design the wear bushing appears to wear more than the seal lips. 

I would assume that one could scientifically change the balance to increase the interval of haulouts. However, it makes sense to me that unless a scientific approach is used, we would be playing Russian roulette with a very expensive part of our boat.

Don't take what I am saying as criticism. I am happy that you achieved your goal. My goal was to haul out every 2 years for more reasons than C-Drive maintenance.

I would urge all readers of this message to stick with proven Amel supplied parts and procedures, rather than changing something that you do not completely understand. I do not have the metallurgical and mechanical engineering expertise to develop a better system than Amel's wear bushing and seals, nor do I believe any of us have that knowledge. 

And, I will take this a step further: Many of the Amel systems that I have been exposed to, obviously take into consideration the required maintenance and the level of experience and knowledge of the person performing the job. When I managed new product development, I used the term "child proof." When I asked my staff if the new product was "child proof," they knew that I was asking if it would pass the test of the most ignorant user. I never met Henri Amel, but from my experience with his boats, I believe he also used my term, or one similar.

Until recently, I had no idea that the Nitrile Buna-N seals are available in a hardness range from 40-90, and I do not know the hardness of the Nitrile Buna-N lip seals that Amel uses. We all know that bronze, brass, and Naval brass are available in different hardnesses. I suspect that none of us know the hardness of the wear bushing that Amel uses, nor do we know the percent of copper, tin, and zinc . Without this information, I believe that changing the balance of wear between the bushing and the seal should not be attempted, unless you understand the huge risk for what, I believe, is very little reward.

Ian, it is very good to have you return to this forum. I have missed you and your posts. Probably none of us have more miles in a Super Maramu than you have.

​Best,​

CW Bill Rouse
Admiral, Texas Navy
Commander Emeritus
Amel School www.amelschool.com
720 Winnie St
Galveston Island, TX 77550




Ian Shepherd
 

Vladimir,

Priviet! I paid €80 to have a new bush made in stainless.I don't consider that expensive especially considering that it has 4 grub screws and not two. I would guess that might be cheaper than a bronze bush from Amel? I wonder how different the material cost really is? Bronze is not that cheap. I have not had any trouble finding a machine shop that can turn stainless. As long as there is an unused bronze bush to copy, I think that we can find where to get them made wherever we are.

Ou darchi

Ian Shepherd SM2K 414 (2003) Crusader Kastelorizo Island Greece


On 07/08/2017 23:06, Vladimir Sonsev sonsev52@... [amelyachtowners] wrote:
 

Hardness of stainless steel 316 does not vary tangible. Bushing from stainless 316 will  definitely last longer, but the bushing will cost much more. 316 steel is expensive and hard to machin. But it is very good corrosion resistant material, good for salt water. If people are interested I can find mashin shop that can make them. We have to order 100 bushings or more. Otherwise setup cost is too much.

Vladimir Sonsev
SM 345
"LIFE IS GOOD"


On Aug 7, 2017 10:57 AM, "'Bill & Judy Rouse' yahoogroups@... [amelyachtowners]" <amelyachtowners@...> wrote:
 
Ian, All, and especially newbies;

Most of you know that I have been and will always be the person in this group that warns everyone about changing an Amel design. It is nothing personal. I love all things Amel and I take it as my responsibility; so, because of that responsibility, I will offer the other side of CRUSADER's report and recommendation...nothing personal, but I am the self-appointed protector of all things Amel, and will always be the one to point out the RISK vs the REWARD in changing an Amel design.

<<<>>>
I am certainly no expert, but I believe that stainless steel comes in at least 5 types and also different hardnesses; and the Nitrile Buna-N seals are made in different hardnesses. Although I personally do not need the answer to the following questions, I believe anyone attempting to follow your recommendation should know: What type of stainless steel and hardness you used? What was the hardness of the seals? What were the engine hours between servicing?

I would guess that to obtain different results than the Amel-proven system, you have to either scientifically solve the wear issue to achieve a different balance between wear of the seal and wear of the bushing, or use a trial and error method. I assume that your method was trial and error, which resulted in changing the balance of wear between the wear bushing and the wear on the lips of the seals; which extended your haulout interval - your goal. 

We must remember that there will be wear between the lips of the seal and the wear bushing on the C-Drive. It is obvious to anyone who has serviced an Amel C-Drive that with the current Amel design the wear bushing appears to wear more than the seal lips. 

I would assume that one could scientifically change the balance to increase the interval of haulouts. However, it makes sense to me that unless a scientific approach is used, we would be playing Russian roulette with a very expensive part of our boat.

Don't take what I am saying as criticism. I am happy that you achieved your goal. My goal was to haul out every 2 years for more reasons than C-Drive maintenance.

I would urge all readers of this message to stick with proven Amel supplied parts and procedures, rather than changing something that you do not completely understand. I do not have the metallurgical and mechanical engineering expertise to develop a better system than Amel's wear bushing and seals, nor do I believe any of us have that knowledge. 

And, I will take this a step further: Many of the Amel systems that I have been exposed to, obviously take into consideration the required maintenance and the level of experience and knowledge of the person performing the job. When I managed new product development, I used the term "child proof." When I asked my staff if the new product was "child proof," they knew that I was asking if it would pass the test of the most ignorant user. I never met Henri Amel, but from my experience with his boats, I believe he also used my term, or one similar.

Until recently, I had no idea that the Nitrile Buna-N seals are available in a hardness range from 40-90, and I do not know the hardness of the Nitrile Buna-N lip seals that Amel uses. We all know that bronze, brass, and Naval brass are available in different hardnesses. I suspect that none of us know the hardness of the wear bushing that Amel uses, nor do we know the percent of copper, tin, and zinc . Without this information, I believe that changing the balance of wear between the bushing and the seal should not be attempted, unless you understand the huge risk for what, I believe, is very little reward.

Ian, it is very good to have you return to this forum. I have missed you and your posts. Probably none of us have more miles in a Super Maramu than you have.

​Best,​

CW Bill Rouse
Admiral, Texas Navy
Commander Emeritus
Amel School www.amelschool.com
720 Winnie St
Galveston Island, TX 77550




Ian Shepherd
 

Interesting.Thank you Craig. I actually put the outer seal facing inwards as per the Amel diagram. My though being that you don't want the spring exposed to sea water. I have made a note of 17-4 and will specify that next time.

You probably know Sanai in Marmaris? Loads of good machine shops there.

Regards

Ian Shepherd SM2K 414 (2003) Crusader Kastelorizo Island Greece


On 08/08/2017 15:00, sangaris@... [amelyachtowners] wrote:
 

Some time ago I asked SKF's engineering about this. Here's their reply to me:
"Craig, 
My educated guess is that the seals are not an issue in this application. The problem is with the Bronze bushing that is being used as a sealing surface. Bronze is generally quite soft and might not have the required hardness of Rockwell C 30 or higher. You have a few options to solve this issue:
• You can put SKF speedi-sleeve gold on the shaft (P/N 99830). You will probably have to install multiple sleeves as you have 3 seals next to each other.
• You can replace the bronze bushing with a hardened wear sleeve for better abrasion resistance. We can offer you a custom wear sleeve if needed.
• You can plate your bushing with a harder material (Chrome, ceramic, etc) to make it wear resistant.
Essentially, the harder the shaft is, the less grooving it will see. I also suggest you to make sure that you grease pack the area between the seals to make sure that the seals not in contact with the oil are well lubricated. A lack of lubrication can cause the seal and surface to wear quicker. Finally I would arrange the seals with 2 facing the water and one facing the oil as long as there is no pressure difference. 
Best regards, Jaydeep Laljani, Application Engineer, SKF USA

I wrote back and said:
"Many thanks for your analysis. Frankly, I have wondered why the manufacturer used Bronze in the first place and not stainless - they actually call it a "wearing-out bushing" (but then they do charge a lot for replacements :-). 
Next month I'm returning to the boat, which is in Turkey, and I can easily have a local shop turn a new bushing in 316 Stainless (the same material as the shaft and propeller, so no electrolysis issues.) I think that would solve the problem without going to sleeves or plating. 
As for the orientation of the seals, I like your suggestion of two facing the water and will do that the next time I change the seals. After all, we're really trying to keep the water out more than keeping the oil in. And, yes, indeed, I always pack the seals with a good water-proof grease and that helps, I'm sure. "

Jaydeep replied with:

"I think you might not get as much life as you want with 316 SS as it is still not up to the required hardness. If you want to go Stainless I recommend 17-4 Stainless steel which is harder. If you are going with the 316 SS I would recommend you to passivate it to improve corrosion resistance. " 

Hope that's helpful.
Cheers, Craig Briggs, SN#68 Sangaris


---In amelyachtowners@..., wrote :

Hardness of stainless steel 316 does not vary tangible. Bushing from stainless 316 will  definitely last longer, but the bushing will cost much more. 316 steel is expensive and hard to machin. But it is very good corrosion resistant material, good for salt water. If people are interested I can find mashin shop that can make them. We have to order 100 bushings or more. Otherwise setup cost is too much.

Vladimir Sonsev
SM 345
"LIFE IS GOOD"


On Aug 7, 2017 10:57 AM, "'Bill & Judy Rouse' yahoogroups@... [amelyachtowners]" <amelyachtowners@...> wrote:
 
Ian, All, and especially newbies;

....
<<<>>>
I am certainly no expert, but I believe that stainless steel comes in at least 5 types and also different hardnesses; and the Nitrile Buna-N seals are made in different hardnesses. Although I personally do not need the answer to the following questions, I believe anyone attempting to follow your recommendation should know: What type of stainless steel and hardness you used? What was the hardness of the seals? What were the engine hours between servicing?

I would guess that to obtain different results than the Amel-proven system, you have to either scientifically solve the wear issue to achieve a different balance between wear of the seal and wear of the bushing, or use a trial and error method. I assume that your method was trial and error, which resulted in changing the balance of wear between the wear bushing and the wear on the lips of the seals; which extended your haulout interval - your goal. 

We must remember that there will be wear between the lips of the seal and the wear bushing on the C-Drive. It is obvious to anyone who has serviced an Amel C-Drive that with the current Amel design the wear bushing appears to wear more than the seal lips. 

I would assume that one could scientifically change the balance to increase the interval of haulouts. However, it makes sense to me that unless a scientific approach is used, we would be playing Russian roulette with a very expensive part of our boat.

Don't take what I am saying as criticism. I am happy that you achieved your goal. My goal was to haul out every 2 years for more reasons than C-Drive maintenance.

I would urge all readers of this message to stick with proven Amel supplied parts and procedures, rather than changing something that you do not completely understand. I do not have the metallurgical and mechanical engineering expertise to develop a better system than Amel's wear bushing and seals, nor do I believe any of us have that knowledge. 

....
Until recently, I had no idea that the Nitrile Buna-N seals are available in a hardness range from 40-90, and I do not know the hardness of the Nitrile Buna-N lip seals that Amel uses. We all know that bronze, brass, and Naval brass are available in different hardnesses. I suspect that none of us know the hardness of the wear bushing that Amel uses, nor do we know the percent of copper, tin, and zinc . Without this information, I believe that changing the balance of wear between the bushing and the seal should not be attempted, unless you understand the huge risk for what, I believe, is very little reward.

Ian, it is very good to have you return to this forum. I have missed you and your posts. Probably none of us have more miles in a Super Maramu than you have.

​Best,​
Bill Rouse


 


Ian Shepherd
 

Bill,

my seals failed at 500 hours on my first boat for the first time, so assembled by Amel. It's too short a period. No signs of fish line either.

Ian Shepherd SM2K 414 (2003) Crusader Kastelorizo Island Greece


On 08/08/2017 16:27, 'Bill & Judy Rouse' yahoogroups@... [amelyachtowners] wrote:
 
Craig,

That is good information, but, you know me....self-proclaimed protector of Amel systems!

Please read my summary of why I believe in Amel's C-Drive design and service procedure:
The C-Drive will accommodate three seals and it is possible to orient two of the seals to either double the seal-capacity to keep oil IN, or keep water OUT. Which is more important? Seals fail and seals wear...and some owners and operators wait until failure before replacing. 

I firmly believe that Amel is correct, and I think that your engineer is mostly correct. The question is this: Which one of the above two choices is Low Risk? The C-Drive is expensive to replace. The C-Drive requires lubrication to keep it from failing. I prefer to ensure that oil stays in the C-Drive, more than I want to ensure that water stays out. My reason is because if oil leaks out, you may not know it until the damage is done...Conversely, if water leaks in, the oil will still have lubricating ability and you will see the evidence of the presence of oil in the reservoir. 

Additionally, I have personally serviced the C-Drive 6 times. I have audited, supervised, and taught C-Drive service another 12 times. I can assure everyone that if you get water egress, you have not followed the procedures, you have not serviced the C-Drive every 800 hours/2 years, or something like monofilament fishing line has ruined the seals.

One more thing about what the engineer wrote: He seems to ignore the fact that the harder the metal, the more that the Nitrile Buna-N seals will wear. Is it possible that Henri Amel knew that if the owner did not see wear-grooves, the owner would ignore the servicing intervals? I personally like to believe that this is part of the explanation because I believe he was a genius...but, you know me....self-proclaimed protector of Amel systems!

CW Bill Rouse
Admiral, Texas Navy
Commander Emeritus
Amel School www.amelschool.com
720 Winnie St
Galveston Island, TX 77550
+1(832) 380-4970




On Tue, Aug 8, 2017 at 10:00 AM, sangaris@... [amelyachtowners] <amelyachtowners@...> wrote:
 

Some time ago I asked SKF's engineering about this. Here's their reply to me:
"Craig, 
My educated guess is that the seals are not an issue in this application. The problem is with the Bronze bushing that is being used as a sealing surface. Bronze is generally quite soft and might not have the required hardness of Rockwell C 30 or higher. You have a few options to solve this issue:
• You can put SKF speedi-sleeve gold on the shaft (P/N 99830). You will probably have to install multiple sleeves as you have 3 seals next to each other.
• You can replace the bronze bushing with a hardened wear sleeve for better abrasion resistance. We can offer you a custom wear sleeve if needed.
• You can plate your bushing with a harder material (Chrome, ceramic, etc) to make it wear resistant.
Essentially, the harder the shaft is, the less grooving it will see. I also suggest you to make sure that you grease pack the area between the seals to make sure that the seals not in contact with the oil are well lubricated. A lack of lubrication can cause the seal and surface to wear quicker. Finally I would arrange the seals with 2 facing the water and one facing the oil as long as there is no pressure difference. 
Best regards, Jaydeep Laljani, Application Engineer, SKF USA

I wrote back and said:
"Many thanks for your analysis. Frankly, I have wondered why the manufacturer used Bronze in the first place and not stainless - they actually call it a "wearing-out bushing" (but then they do charge a lot for replacements :-). 
Next month I'm returning to the boat, which is in Turkey, and I can easily have a local shop turn a new bushing in 316 Stainless (the same material as the shaft and propeller, so no electrolysis issues.) I think that would solve the problem without going to sleeves or plating. 
As for the orientation of the seals, I like your suggestion of two facing the water and will do that the next time I change the seals. After all, we're really trying to keep the water out more than keeping the oil in. And, yes, indeed, I always pack the seals with a good water-proof grease and that helps, I'm sure. "

Jaydeep replied with:

"I think you might not get as much life as you want with 316 SS as it is still not up to the required hardness. If you want to go Stainless I recommend 17-4 Stainless steel which is harder. If you are going with the 316 SS I would recommend you to passivate it to improve corrosion resistance. " 

Hope that's helpful.
Cheers, Craig Briggs, SN#68 Sangaris


---In amelyachtowners@yahoogroups.com, wrote :

Hardness of stainless steel 316 does not vary tangible. Bushing from stainless 316 will  definitely last longer, but the bushing will cost much more. 316 steel is expensive and hard to machin. But it is very good corrosion resistant material, good for salt water. If people are interested I can find mashin shop that can make them. We have to order 100 bushings or more. Otherwise setup cost is too much.

Vladimir Sonsev
SM 345
"LIFE IS GOOD"


On Aug 7, 2017 10:57 AM, "'Bill & Judy Rouse' yahoogroups@... [amelyachtowners]" <amelyachtowners@yahoogroups.com> wrote:
 
Ian, All, and especially newbies;

....
<<<>>>
I am certainly no expert, but I believe that stainless steel comes in at least 5 types and also different hardnesses; and the Nitrile Buna-N seals are made in different hardnesses. Although I personally do not need the answer to the following questions, I believe anyone attempting to follow your recommendation should know: What type of stainless steel and hardness you used? What was the hardness of the seals? What were the engine hours between servicing?

I would guess that to obtain different results than the Amel-proven system, you have to either scientifically solve the wear issue to achieve a different balance between wear of the seal and wear of the bushing, or use a trial and error method. I assume that your method was trial and error, which resulted in changing the balance of wear between the wear bushing and the wear on the lips of the seals; which extended your haulout interval - your goal. 

We must remember that there will be wear between the lips of the seal and the wear bushing on the C-Drive. It is obvious to anyone who has serviced an Amel C-Drive that with the current Amel design the wear bushing appears to wear more than the seal lips. 

I would assume that one could scientifically change the balance to increase the interval of haulouts. However, it makes sense to me that unless a scientific approach is used, we would be playing Russian roulette with a very expensive part of our boat.

Don't take what I am saying as criticism. I am happy that you achieved your goal. My goal was to haul out every 2 years for more reasons than C-Drive maintenance.

I would urge all readers of this message to stick with proven Amel supplied parts and procedures, rather than changing something that you do not completely understand. I do not have the metallurgical and mechanical engineering expertise to develop a better system than Amel's wear bushing and seals, nor do I believe any of us have that knowledge. 

....
Until recently, I had no idea that the Nitrile Buna-N seals are available in a hardness range from 40-90, and I do not know the hardness of the Nitrile Buna-N lip seals that Amel uses. We all know that bronze, brass, and Naval brass are available in different hardnesses. I suspect that none of us know the hardness of the wear bushing that Amel uses, nor do we know the percent of copper, tin, and zinc . Without this information, I believe that changing the balance of wear between the bushing and the seal should not be attempted, unless you understand the huge risk for what, I believe, is very little reward.

Ian, it is very good to have you return to this forum. I have missed you and your posts. Probably none of us have more miles in a Super Maramu than you have.

​Best,​
Bill Rouse


 



Ian Shepherd
 

Hi Bob,

thanks for the info. Clearly Amel have picked up on the idea and are moving in that direction. Can't help thinking that Bill is a bit behind the drag curve on this one! Sorry I missed you in Turkey last year.

Best wishes

Ian Shepherd SM2K 414 (2003) Crusader Kastelorizo Island Greece


On 09/08/2017 03:18, rossidesigngroup@... [amelyachtowners] wrote:
 
I think someone else posted that Amel had been experimenting with stainless WOBs but had not had enough time yet to evaluate them.

I've made a couple of posts on the experimental stainless WOB that Amel Iinadvertantly?) sent me. You can search for the posts including responses.  I finally put the WOB on about a year ago in Marmaris, Turkey (August, 2016) and will probably run it until I detect water in the reservoir. 

These are excerpts from 2 previous postings I made on this.  THE PICS ARE  A WOB AS RECEIVED FROM AMEL!

In March, 2014 I ordered and received FROM AMEL a bronze wearing out 
bearing that had a sort of Speedi-Seal stainless/inox facing on the 
surface that the seals go over. I have posted detailed pics at Dropbox 

LATER
Mystery solved!  I just got off the phone with Maud (ordering new parts including an additional spare for my spare prop WOB (I admit it, like lots of us I carry 2 spares of certain items).  

I asked her about the unusual WOB that I had received more than a year ago and described it (bronze with stainless or chromed steel face).  She explained to me that it was a "test" from Amel to see if it would prolong the life of the part. She said that several were sent out for this purpose and asked me how it was doing.  I have not installed it but promised I would report back.  Here, again are pics of the part   Amel Test WOB (4 photos)    Bob Rossi SM 429 KAIMI

Like many of us I ordered the WOB after I installed one and then waited 2 years... I finally installed the Amel stainless WOB a year ago in Marmaris around 8/2016.  I have not heard of another owner receiving the test WOB but there was a posting regarding Amels testing of these with a note that not enough time had elapsed to reach a conclusion.


greatketch@...
 

There is having the outer seals facing the other way, but protecting the spring from seawater is not it.

Lip seals are designed to "pump" fluid as the shaft turns, from the "outside" to the "inside".  This pumping action is obviously VERY tiny. It helps in normal installations with oil on the inside and air on the outside to move any small amount of seeping oil back into the gearbox.

Our application is quite different.  The shaft seal on the C-Drive needs to keep two incompatible liquids apart. It is not something one standard single-lip seal can do, even when it is functioning perfectly.  The three seals are NOT there for triple redundancy, rather they work together as an integrated design.  

If the outer seal was installed "normally" it would be constantly moving a tiny amount of water toward the oil chamber.  Obviously not a good idea.  When people put these seals together backwards, and find water in the transmission, they assume the seal has failed early, when it is actually doing just what it is designed to do!

Think of it this way, the outer seal is working to keep the water in the ocean and the other two are keeping the oil in the gear box.  One could make a reasonable argument (as SKF tech support does in the email quoted in this thread) that the best way to install them is two keeping water out and one keeping oil in, but that would be an incremental change, not a dramatic one.

The upshot of this is once the outer seal fails, you will get water into the oil, even if the two inner seals are in perfect condition.  On the other hand, the chances for a rapid, catastrophic lose of oil are very low.

The biggest wear factor on these seals (Absent fishing line!) is grit in the water. Sand, mud, slit, all will score the wear bushing. One hour motoring in muddy river water is much harder on the wear bushing than many hours in clear tropical ocean water.  No matter what material the bushing is made of, it will wear, but some materials (stainless) will wear slower than others (bronze). 

Why did Amel chose bronze for this part?  I do not know.  It is softer than any seal maker would recommend, but remember that hardness recommendation is for hard to replace shafts, not replaceable bushings. Certainly bronze is easier to machine than stainless.  Based on comments to this group previously, Amel apparently tested a stainless bushing, but they have now gone back to supplying bronze.  Why?  I do not know.

Unless it is really bad, the rubber parts don't get chewed up as fast as you might think.  The grit "sticks" to the rubber and is not abrading it that much. That is how rubber can wear away metal without being destroyed itself.  But... once the bushing surface is damaged, THEN the seal gets worn quite quickly.

If you do decide to have a custom wear bushing made, be sure the machinist knows what is being made and what's important.  Just by way of example, the surface needs to be polished to (at least) the level specified by the seal manufacturer.  There should also be NO spiral tooling marks on the surface, in either direction--even before polishing.  This is NOT just a hunk of metal of a certain size. There is a lot of un-obvious detail here, and all of it important. If the machinist does not seem interested in these details, then he is the wrong guy for the job. Without knowing the details you might get lucky and have it work... or not. 

Bill Kinney
SM160, Harmonie
Bar Harbor, Maine





Ian Shepherd
 

Bill you are absolutely right. I checked the Amel diagram and the spring on the outer seal should face the prop and the springs on the other two seals should face into the transmission box. This was the way that I had the seals during the 7 year experiment. I remember having to drill into the outer seals spring when I made a hole for the extracting screw. My apologies for suggesting putting them in a the other way round.

Regarding the debris situation, the rubber tube should help to keep fishing line etc out. My tube was beginning to deteriorate so I had a Teflon sleeve made up to fit between the bearing boss and the prop. As an after thought, at the next haul out  I may have the sleeve turned down a fraction and fit O-Rings to each end face so that when the prop is tightened up, the O-Rings make a good seal and keep even mud particles out. The sleeve could also be packed with grease to improve the lubrication of the out seal.

Regards

Ian shepherd SM2K 414 Crusader (2003) Greece


On 11/08/2017 17:33, greatketch@... [amelyachtowners] wrote:
 

There is having the outer seals facing the other way, but protecting the spring from seawater is not it.


Lip seals are designed to "pump" fluid as the shaft turns, from the "outside" to the "inside".  This pumping action is obviously VERY tiny. It helps in normal installations with oil on the inside and air on the outside to move any small amount of seeping oil back into the gearbox.

Our application is quite different.  The shaft seal on the C-Drive needs to keep two incompatible liquids apart. It is not something one standard single-lip seal can do, even when it is functioning perfectly.  The three seals are NOT there for triple redundancy, rather they work together as an integrated design.  

If the outer seal was installed "normally" it would be constantly moving a tiny amount of water toward the oil chamber.  Obviously not a good idea.  When people put these seals together backwards, and find water in the transmission, they assume the seal has failed early, when it is actually doing just what it is designed to do!

Think of it this way, the outer seal is working to keep the water in the ocean and the other two are keeping the oil in the gear box.  One could make a reasonable argument (as SKF tech support does in the email quoted in this thread) that the best way to install them is two keeping water out and one keeping oil in, but that would be an incremental change, not a dramatic one.

The upshot of this is once the outer seal fails, you will get water into the oil, even if the two inner seals are in perfect condition.  On the other hand, the chances for a rapid, catastrophic lose of oil are very low.

The biggest wear factor on these seals (Absent fishing line!) is grit in the water. Sand, mud, slit, all will score the wear bushing. One hour motoring in muddy river water is much harder on the wear bushing than many hours in clear tropical ocean water.  No matter what material the bushing is made of, it will wear, but some materials (stainless) will wear slower than others (bronze). 

Why did Amel chose bronze for this part?  I do not know.  It is softer than any seal maker would recommend, but remember that hardness recommendation is for hard to replace shafts, not replaceable bushings. Certainly bronze is easier to machine than stainless.  Based on comments to this group previously, Amel apparently tested a stainless bushing, but they have now gone back to supplying bronze.  Why?  I do not know.

Unless it is really bad, the rubber parts don't get chewed up as fast as you might think.  The grit "sticks" to the rubber and is not abrading it that much. That is how rubber can wear away metal without being destroyed itself.  But... once the bushing surface is damaged, THEN the seal gets worn quite quickly.

If you do decide to have a custom wear bushing made, be sure the machinist knows what is being made and what's important.  Just by way of example, the surface needs to be polished to (at least) the level specified by the seal manufacturer.  There should also be NO spiral tooling marks on the surface, in either direction--even before polishing.  This is NOT just a hunk of metal of a certain size. There is a lot of un-obvious detail here, and all of it important. If the machinist does not seem interested in these details, then he is the wrong guy for the job. Without knowing the details you might get lucky and have it work... or not. 

Bill Kinney
SM160, Harmonie
Bar Harbor, Maine






rossirossix4
 

Hi Everyone,
Given recent postings on the WOB and my experience about a month ago I think it is a good time to post regarding an experiemental WOB that I had received from Amel.  I had received it in March, 2014 and thought, mistakenly that this was simply the new design that AMEL provided.  Instead, I learned later that these were trial versions that Amel had somehow provided to me.  Not sure if anyone else got them.  So here are the pics I posted back in September,  2014 -- https://www.dropbox.com/sc/1tompsdjss3rr0r/AACGUoVzzawY5RnlyKpnjwRga
.
In a phone conversation with Maud she confirmed that Amel was trying these out.  About 2 years ago I had installed this new type WOB in Turkey and changed it here in Malta and examined it carefully (note we visited Croatia and Venice on the way back, so the miles are there).  Please also note that I am making no claims about whether Amel should convert to these but I will tell you what I reported to Amel--which is that I was replacing the O ring inside and re-using the WOB!  Below is the content of my email to Maud and her response back to me.  I thought it was important to provide the information to Amel and give them time before placing it in front of the group.  Please also note that Adm Bill was privy to the info and he has contacted Amel via one of his contacts there to suggest they consider switching to the new WOB.

OK...the email to Maud on April 4 and her response on April 5.

"Hi Maud,

About 3.5 years ago you sent me an "experimental" WOB that Amel was trying out.  It is a normal bronze WOB with a stainless surface where the lip seals mount.  I was confused about it but in a later telephone conversation you talked with someone at Amel and then explained to me that Amel was trying out the new special WOB.  I promised to mount it and report back to you.

I serviced the Amel drive on my Super Maramu KAIMI #429 about 2 years ago and installed the special WOB.  Last week I serviced it again. There was virtually no wear on the WOB.  There was no evidence of water in the drive oil (90 wt) and the springs inside the seals were not rusted (I pack them with grease).

It is my impression that the WOB did very well.  While I could see some "polishing" could not detect any ridge or groove with my fingernail and I replaced the O ring inside the WOB and am re-using the WOB.   I plan to report back again on the next service in a year or 2.

I have included a link to photos of the removed WOB.  For comparison I show a regular used WOB.  You are welcome to forward this email to any others at Amel and I will be happy to answer any other questions that you have.

Click on individual images for larger photo --
https://photos.app.goo.gl/cW2QtzN7OeKaupoP2

Robert Rossi  SM#429 KAIMI"

Response back from Maud--
"Dear Robert,
Thank you for your nice message and detailed report. I will forward the results of your test to the AMEL technical department and I am certain they will be glad to hear it is very positive.
Thank you again for being such a supportive customer!!
Have a nice day.
With my kindest regards,

Maud TOUILLET
Service clientèle/Customer service"

Highlights--I could detect NO wear other than a bit of polishing where normally you would see a groove...note the used bronze version as a comparison.  There was no evidence of water in the 90 wt oil which I actually ran back through my Mr.Funnel to see if there was water--none-- and now have re-stored for possible future use.  Note also that there was no noticeable rust on the springs in the seals.  And, as noted, I am re-using the WOB.  We plan on pulling out for hurricane season in the Caribbean 14 months from now and I will re-check it.  Ironically, the entire process left me kind of upset with myself for even doing the change!

https://photos.app.goo.gl/cW2QtzN7OeKaupoP2

Bob and Suzanne, KAIMI SM429 Gozo in the Maltese archipelago