[Amel Yacht Owners] Re: Diaphragm Bilge Pump failure.


VLADIMIR SONSEV
 

 Offshore racing council required two electrical and two manual bilge pumps. One manual pump must be down below.
Just for your information.

Vladimir
SM "Life is Good"

On Dec 2, 2017 13:58, "greatketch@... [amelyachtowners]" <amelyachtowners@...> wrote:
 

I had a boss once whose favorite line was, "Show me the data." I learned a lot from him...  

Ratings are all fine and good, but the real world can always change things. So I just timed how long it took my Amel original diaphragm pump to move 12 liters of water: 42 seconds. A flow rate of: 17 liters per minute (or 4.5GPM)  I have read the "32 l/min" number several times, but don't know its original source.

Whenever I see someone write down a number and proclaim that "this is the minimum capacity for a bilge pump for this boat" I wonder how they came up with that number.  

I think of bilge pumps in two categories:  Dewatering and emergency.  

Dewatering is just the normal day to day emptying of the bilge.  On most boats that would include shaft drip, rain water leaks, etc.  We don't have those, so for us it is just the routine emptying of gray water from the sump.   The primary pump selection issue here is not about capacity, but rather picking a pump that will not choke on any lumpy bits from the galley sink.  Given that requirement, we do not have a lot of options. 

An emergency bilge pump is another matter. Any hole in the hull below the water line will overwhelm most bilge pumps.  8gpm is a good number for a 1/2 inch hole, and the flow rate rises with the square of the diameter... so a 1 inch hole would be 24gpm, and a 2 inch hole pushes 100gpm.  That's a LOT.

A boat like an Amel with watertight bulkheads has an extra issue.  Any hole outside the engine room can not drain to the bilge anywhere near as fast as water comes in from the ocean.  So the size of the pump in the sump doesn't matter.

My own personnel takeaway is that a bilge pump that could actually keep up with a significant hole in the boat (on an Amel, maybe a broken engine raw water hose?) is larger than any recommendation I have seen, and borders on impractical.  If you have a hole in the boat too big to plug with your thumb, and you can't stop it, you are sinking--eventually. (Watertight bulkheads aside, of course!)

Ratings on centrifugal bilge pumps are a pretty sad joke. They are all rated at Zero head, and that's just plain goofy. Most of them don't even supply a curve of output flow vs head, and even if they did most people would not know how to interpret it ("pressure head" is much more complex than just discharge height.)  In a real world installation you'd be very lucky to get even 1/4 of the flow rate listed on the box.

All that is a very long winded way of saying... With all the variables and considerations I don't pretend to know what a "proper" capacity is. I do not even know what kind of logical criteria one would use to set one.  I have seen many "authorities" and committees proclaim a number, but their logic is either (arguably) flawed or not specified.

On Harmonie we have: 
  • The standard Amel installed diaphragm bilge pump,  
  • A bilge level alarm,
  • An identical spare electric pump ready to plug in as a replacement if needed, 
  • The Amel installed manual bilge pump, 
  • And a portable manual bilge pump for really serious emergencies.  
I'm comfortable with that list.

Bill Kinney
SM160, Harmonie
Fort Lauderdale, FL







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

Bill,

   Thanks for the confirmation on the duckbills being nitrile in the Sealand pump.  I suspect that this pump would be great for pumping the sump.   What is you opinion about the capacity of this pump in regards to being the sole electric bilge pump aboard?   I am used to installing centrifugal pumps in boats this size with ratings 10X higher.  I think something as small as a 1/2” hole 4’ below the WL would flow almost 8 GPM….

James

Maramu #220 

On Dec 1, 2017, at 10:58 PM, greatketch@... [amelyachtowners] <amelyachtowners@yahoogroups.com> wrote:

The only rubber in the T-series pumps in contact with pumped water are the joker valves.  


The sealand joker valves (they call them "duckbill valves") are made of nitrile rubber, which is good for oil contact.



Danny and Yvonne SIMMS
 

Hi Bill,

Have to agree with you. No bilge pump of a size you could fit in a boat would deal with water coming in from a hole in the hull. Anyone who has in water swapped or removed for cleaning a through hull transducer would have any illusions about this. The volume of water gushing in from this very moderate hole is sobering. Henri's watertight bulkheads are the only sensible protection from a breach in the hull. 

Regards

Danny

SM 299 Ocean Pearl

On 03 December 2017 at 06:58 "greatketch@... [amelyachtowners]" <amelyachtowners@...> wrote:

 

 

I had a boss once whose favorite line was, "Show me the data." I learned a lot from him...  

Ratings are all fine and good, but the real world can always change things. So I just timed how long it took my Amel original diaphragm pump to move 12 liters of water: 42 seconds. A flow rate of: 17 liters per minute (or 4.5GPM)  I have read the "32 l/min" number several times, but don't know its original source.

Whenever I see someone write down a number and proclaim that "this is the minimum capacity for a bilge pump for this boat" I wonder how they came up with that number.  

I think of bilge pumps in two categories:  Dewatering and emergency.  

Dewatering is just the normal day to day emptying of the bilge.  On most boats that would include shaft drip, rain water leaks, etc.  We don't have those, so for us it is just the routine emptying of gray water from the sump.   The primary pump selection issue here is not about capacity, but rather picking a pump that will not choke on any lumpy bits from the galley sink.  Given that requirement, we do not have a lot of options. 

An emergency bilge pump is another matter. Any hole in the hull below the water line will overwhelm most bilge pumps.  8gpm is a good number for a 1/2 inch hole, and the flow rate rises with the square of the diameter... so a 1 inch hole would be 24gpm, and a 2 inch hole pushes 100gpm.  That's a LOT.

A boat like an Amel with watertight bulkheads has an extra issue.  Any hole outside the engine room can not drain to the bilge anywhere near as fast as water comes in from the ocean.  So the size of the pump in the sump doesn't matter.

My own personnel takeaway is that a bilge pump that could actually keep up with a significant hole in the boat (on an Amel, maybe a broken engine raw water hose?) is larger than any recommendation I have seen, and borders on impractical.  If you have a hole in the boat too big to plug with your thumb, and you can't stop it, you are sinking--eventually. (Watertight bulkheads aside, of course!)

Ratings on centrifugal bilge pumps are a pretty sad joke. They are all rated at Zero head, and that's just plain goofy. Most of them don't even supply a curve of output flow vs head, and even if they did most people would not know how to interpret it ("pressure head" is much more complex than just discharge height.)  In a real world installation you'd be very lucky to get even 1/4 of the flow rate listed on the box.

All that is a very long winded way of saying... With all the variables and considerations I don't pretend to know what a "proper" capacity is. I do not even know what kind of logical criteria one would use to set one.  I have seen many "authorities" and committees proclaim a number, but their logic is either (arguably) flawed or not specified.

On Harmonie we have: 
  • The standard Amel installed diaphragm bilge pump,  
  • A bilge level alarm,
  • An identical spare electric pump ready to plug in as a replacement if needed, 
  • The Amel installed manual bilge pump, 
  • And a portable manual bilge pump for really serious emergencies.  
I'm comfortable with that list.

Bill Kinney
SM160, Harmonie
Fort Lauderdale, FL







---In amelyachtowners@..., <lokiyawl2@...> wrote :

Bill,

   Thanks for the confirmation on the duckbills being nitrile in the Sealand pump.  I suspect that this pump would be great for pumping the sump.   What is you opinion about the capacity of this pump in regards to being the sole electric bilge pump aboard?   I am used to installing centrifugal pumps in boats this size with ratings 10X higher.  I think something as small as a 1/2” hole 4’ below the WL would flow almost 8 GPM….

James

Maramu #220 

On Dec 1, 2017, at 10:58 PM, greatketch@... [amelyachtowners] <amelyachtowners@...> wrote:

The only rubber in the T-series pumps in contact with pumped water are the joker valves.  


The sealand joker valves (they call them "duckbill valves") are made of nitrile rubber, which is good for oil contact.

 

 


 


greatketch@...
 

I had a boss once whose favorite line was, "Show me the data." I learned a lot from him...  

Ratings are all fine and good, but the real world can always change things. So I just timed how long it took my Amel original diaphragm pump to move 12 liters of water: 42 seconds. A flow rate of: 17 liters per minute (or 4.5GPM)  I have read the "32 l/min" number several times, but don't know its original source.

Whenever I see someone write down a number and proclaim that "this is the minimum capacity for a bilge pump for this boat" I wonder how they came up with that number.  

I think of bilge pumps in two categories:  Dewatering and emergency.  

Dewatering is just the normal day to day emptying of the bilge.  On most boats that would include shaft drip, rain water leaks, etc.  We don't have those, so for us it is just the routine emptying of gray water from the sump.   The primary pump selection issue here is not about capacity, but rather picking a pump that will not choke on any lumpy bits from the galley sink.  Given that requirement, we do not have a lot of options. 

An emergency bilge pump is another matter. Any hole in the hull below the water line will overwhelm most bilge pumps.  8gpm is a good number for a 1/2 inch hole, and the flow rate rises with the square of the diameter... so a 1 inch hole would be 24gpm, and a 2 inch hole pushes 100gpm.  That's a LOT.

A boat like an Amel with watertight bulkheads has an extra issue.  Any hole outside the engine room can not drain to the bilge anywhere near as fast as water comes in from the ocean.  So the size of the pump in the sump doesn't matter.

My own personnel takeaway is that a bilge pump that could actually keep up with a significant hole in the boat (on an Amel, maybe a broken engine raw water hose?) is larger than any recommendation I have seen, and borders on impractical.  If you have a hole in the boat too big to plug with your thumb, and you can't stop it, you are sinking--eventually. (Watertight bulkheads aside, of course!)

Ratings on centrifugal bilge pumps are a pretty sad joke. They are all rated at Zero head, and that's just plain goofy. Most of them don't even supply a curve of output flow vs head, and even if they did most people would not know how to interpret it ("pressure head" is much more complex than just discharge height.)  In a real world installation you'd be very lucky to get even 1/4 of the flow rate listed on the box.

All that is a very long winded way of saying... With all the variables and considerations I don't pretend to know what a "proper" capacity is. I do not even know what kind of logical criteria one would use to set one.  I have seen many "authorities" and committees proclaim a number, but their logic is either (arguably) flawed or not specified.

On Harmonie we have: 
  • The standard Amel installed diaphragm bilge pump,  
  • A bilge level alarm,
  • An identical spare electric pump ready to plug in as a replacement if needed, 
  • The Amel installed manual bilge pump, 
  • And a portable manual bilge pump for really serious emergencies.  
I'm comfortable with that list.

Bill Kinney
SM160, Harmonie
Fort Lauderdale, FL







---In amelyachtowners@..., <lokiyawl2@...> wrote :

Bill,

   Thanks for the confirmation on the duckbills being nitrile in the Sealand pump.  I suspect that this pump would be great for pumping the sump.   What is you opinion about the capacity of this pump in regards to being the sole electric bilge pump aboard?   I am used to installing centrifugal pumps in boats this size with ratings 10X higher.  I think something as small as a 1/2” hole 4’ below the WL would flow almost 8 GPM….

James

Maramu #220 

On Dec 1, 2017, at 10:58 PM, greatketch@... [amelyachtowners] <amelyachtowners@...> wrote:

The only rubber in the T-series pumps in contact with pumped water are the joker valves.  


The sealand joker valves (they call them "duckbill valves") are made of nitrile rubber, which is good for oil contact.



James Alton
 

Bill,

   Thanks for the confirmation on the duckbills being nitrile in the Sealand pump.  I suspect that this pump would be great for pumping the sump.   What is you opinion about the capacity of this pump in regards to being the sole electric bilge pump aboard?   I am used to installing centrifugal pumps in boats this size with ratings 10X higher.  I think something as small as a 1/2” hole 4’ below the WL would flow almost 8 GPM….

James

Maramu #220 

On Dec 1, 2017, at 10:58 PM, greatketch@... [amelyachtowners] <amelyachtowners@...> wrote:

The only rubber in the T-series pumps in contact with pumped water are the joker valves.  


The sealand joker valves (they call them "duckbill valves") are made of nitrile rubber, which is good for oil contact.



greatketch@...
 

The only rubber in the T-series pumps in contact with pumped water are the joker valves.  

The sealand joker valves (they call them "duckbill valves") are made of nitrile rubber, which is good for oil contact.


Bill & Judy Rouse <yahoogroups@...>
 

I believe the original Amel electric bilge pump for the gray water bilge is 32 liters/min 


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 Dec 1, 2017 12:41, "James Sterling jamessterling88@... [amelyachtowners]" <amelyachtowners@...> wrote:
 

Most of the Jabsco 'designated' bilge pumps of this type such as their belt driven bellows/diaphragm models range from 3.5 to 8 gpm.  I think my current model is around 5 gpm.  I'm betting the original Amel pump was close to that also but may be wrong.  I see no reason the Sealand wouldn't serve as a replacement. All suggestions so far have been in the same general area.


S/V Longbow SM2K #418






Sent from Yahoo Mail. Get the app


On Thursday, November 30, 2017, 4:17:55 PM CST, James Alton lokiyawl2@... [amelyachtowners] <amelyachtowners@yahoogroups.com> wrote:


 

Oops, typo.  The T series pump is supposed to be rated at 300 GPH, not GPM,  sorry for not proof reading my previous post more carefully.


James
SV Suneno,  Maramu #220

On Nov 30, 2017, at 5:52 PM, James Alton lokiyawl2@... [amelyachtowners] <amelyachtowners@yahoo groups.com> wrote:

Duane,


   No, my boat still has the original Amel installed diaphragm pump.  The T series pumps that I have had experience with were used for black water tank pump out.  So far none of my customers has managed to clog or kill one of these pumps.  The pump is supposed to move 300 GPM so I think it might be a little small for a primary bilge pump.  I suspect that this pump could be quite reliable as a bilge pump but do not have any experience to support that.  One concern would be whether the rubber used in the pump can handle oil that might be in the bilge,  perhaps someone knows?

James
SV Sueno,  Maramu #220

On Nov 30, 2017, at 3:54 PM, sailor63109@... [amelyachtowners] <amelyachtowners@yahoogroups.com> wrote:

James,


I'm just curious...is this your bilge pump?

Duane
Wanderer, SM#477





James Sterling
 

Most of the Jabsco 'designated' bilge pumps of this type such as their belt driven bellows/diaphragm models range from 3.5 to 8 gpm.  I think my current model is around 5 gpm.  I'm betting the original Amel pump was close to that also but may be wrong.  I see no reason the Sealand wouldn't serve as a replacement. All suggestions so far have been in the same general area.


S/V Longbow SM2K #418






Sent from Yahoo Mail. Get the app


On Thursday, November 30, 2017, 4:17:55 PM CST, James Alton lokiyawl2@... [amelyachtowners] wrote:


 

Oops, typo.  The T series pump is supposed to be rated at 300 GPH, not GPM,  sorry for not proof reading my previous post more carefully.


James
SV Suneno,  Maramu #220

On Nov 30, 2017, at 5:52 PM, James Alton lokiyawl2@... [amelyachtowners] <amelyachtowners@...> wrote:

Duane,


   No, my boat still has the original Amel installed diaphragm pump.  The T series pumps that I have had experience with were used for black water tank pump out.  So far none of my customers has managed to clog or kill one of these pumps.  The pump is supposed to move 300 GPM so I think it might be a little small for a primary bilge pump.  I suspect that this pump could be quite reliable as a bilge pump but do not have any experience to support that.  One concern would be whether the rubber used in the pump can handle oil that might be in the bilge,  perhaps someone knows?

James
SV Sueno,  Maramu #220

On Nov 30, 2017, at 3:54 PM, sailor63109@... [amelyachtowners] <amelyachtowners@...> wrote:

James,


I'm just curious...is this your bilge pump?

Duane
Wanderer, SM#477





James Alton
 

Oops, typo.  The T series pump is supposed to be rated at 300 GPH, not GPM,  sorry for not proof reading my previous post more carefully.

James
SV Suneno,  Maramu #220

On Nov 30, 2017, at 5:52 PM, James Alton lokiyawl2@... [amelyachtowners] <amelyachtowners@...> wrote:

Duane,


   No, my boat still has the original Amel installed diaphragm pump.  The T series pumps that I have had experience with were used for black water tank pump out.  So far none of my customers has managed to clog or kill one of these pumps.  The pump is supposed to move 300 GPM so I think it might be a little small for a primary bilge pump.  I suspect that this pump could be quite reliable as a bilge pump but do not have any experience to support that.  One concern would be whether the rubber used in the pump can handle oil that might be in the bilge,  perhaps someone knows?

James
SV Sueno,  Maramu #220

On Nov 30, 2017, at 3:54 PM, sailor63109@... [amelyachtowners] <amelyachtowners@...> wrote:

James,


I'm just curious...is this your bilge pump?

Duane
Wanderer, SM#477





James Alton
 

Duane,

   No, my boat still has the original Amel installed diaphragm pump.  The T series pumps that I have had experience with were used for black water tank pump out.  So far none of my customers has managed to clog or kill one of these pumps.  The pump is supposed to move 300 GPM so I think it might be a little small for a primary bilge pump.  I suspect that this pump could be quite reliable as a bilge pump but do not have any experience to support that.  One concern would be whether the rubber used in the pump can handle oil that might be in the bilge,  perhaps someone knows?

James
SV Sueno,  Maramu #220

On Nov 30, 2017, at 3:54 PM, sailor63109@... [amelyachtowners] <amelyachtowners@...> wrote:

James,


I'm just curious...is this your bilge pump?

Duane
Wanderer, SM#477