Topics

deck leak


Miles
 

Deck leak.

Hello All,

My boat has developed a small deck leak over the chart table.  So far it is small and is visible only by looking at the slight bubbling and dampness in the head liner.  I suspect the main traveler track, but I am hoping that someone else has had a similar problem and can offer suggestions. 
Miles
Ladybug  sm216  Newport, RI 


Thomas Peacock
 

We have also experienced a small deck leak, albeit forward of yours. 
What I have found is the screws that hold in the metal plating associated with the windows can work loose a little bit, allowing water to come in through the screw hole. This can happen even if the screw looks okay on the outside. 

Tom Peacock
SM 240 Aletes 
Chesapeake Bay

On Sep 19, 2020, at 12:52 PM, Miles <milesbid@...> wrote:



Deck leak.

Hello All,

My boat has developed a small deck leak over the chart table.  So far it is small and is visible only by looking at the slight bubbling and dampness in the head liner.  I suspect the main traveler track, but I am hoping that someone else has had a similar problem and can offer suggestions. 
Miles
Ladybug  sm216  Newport, RI 


--
Tom Peacock
SM 240 Aletes
Chesapeake Bay


Karen Smith
 

Hello Amelians,

Here are our thoughts about this deck leak!

Any deck leak, no matter how small, in the main cabin of a Super Maramu is a serious issue that needs to be addressed RIGHT AWAY.  
This is the voice of painful experience. A TINY little salt line was all that alerted us to one of the biggest jobs we have had to do to our boat.

Here is why...

From the aft edge of the hatch in the main saloon forward, the deck is pretty standard balsa cored deck. 
Right behind the hatch, the deck surface rises about 3 inches, while the cabin ceiling height does not change. 
 
The cabin ceiling here is thin (4-6mm plywood) and there is an empty space between the cabin ceiling and the structural underside of the deck. 
If there is ANY leak into this space, the water is free to roll around, and will find a place to drip down probably quite remote from the actual source.

What makes this situation so serious, is the back edge of the balsa core on the forward deck is not sealed, and is exposed into this space. It will soak up that water, and rot.  This is a big expensive repair to do right.  

Leaks into this space can come from the traveler, but more likely is from the hatch in the main cabin.  

There is a hardwood frame around the hatch opening, and the hatch frame is screwed into this with wood screws.  
 A lot of force is applied to the screws that secure the hinge side of the frame.  
If one of these starts to leak, the wood saturates, and water is then deposited into that empty space between the sailing and the deck, and problems start. 

Karen Smith & Bill Kinney
SM #160
Annapolis, MD


James Alton
 

Bill and Karen,

    You know your stuff Bill, thanks for the alert on the exposed balsa core.  When it comes to balsa core, prevention of damage is certainly far preferable to replacement!  End grain balsa is a fantastic core material but balsa wood is considered “perishable” as compared to more durable species of wood.  Keep it dry and it can last almost forever but if it stays wet for long it can rot pretty quickly unfortunately. 

    I am not sure if my Maramu has the same exposed core issue in your alert but I would like to investigate and if so to seal it preemptively before damage occurs.  Can you tell me what has to be removed to inspect the area in question?  

Best of luck with the fishing and keep having fun you two!

James
SV Sueno
Maramu #220


On Sep 20, 2020, at 8:41 PM, Karen Smith via groups.io <karenharmonie@...> wrote:

Hello Amelians,

Here are our thoughts about this deck leak!

Any deck leak, no matter how small, in the main cabin of a Super Maramu is a serious issue that needs to be addressed RIGHT AWAY.  
This is the voice of painful experience. A TINY little salt line was all that alerted us to one of the biggest jobs we have had to do to our boat.

Here is why...

From the aft edge of the hatch in the main saloon forward, the deck is pretty standard balsa cored deck. 
Right behind the hatch, the deck surface rises about 3 inches, while the cabin ceiling height does not change. 
 
The cabin ceiling here is thin (4-6mm plywood) and there is an empty space between the cabin ceiling and the structural underside of the deck. 
If there is ANY leak into this space, the water is free to roll around, and will find a place to drip down probably quite remote from the actual source.

What makes this situation so serious, is the back edge of the balsa core on the forward deck is not sealed, and is exposed into this space. It will soak up that water, and rot.  This is a big expensive repair to do right.  

Leaks into this space can come from the traveler, but more likely is from the hatch in the main cabin.  

There is a hardwood frame around the hatch opening, and the hatch frame is screwed into this with wood screws.  
 A lot of force is applied to the screws that secure the hinge side of the frame.  
If one of these starts to leak, the wood saturates, and water is then deposited into that empty space between the sailing and the deck, and problems start. 

Karen Smith & Bill Kinney
SM #160
Annapolis, MD

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Bill & Karen and everyone,

I love your sketch and simple explanation of potentially a serious issue. I will add a word of caution. Small cracks in the gelcoat of any Amel can possibly lead to a serious core moisture problem. 

How many of us have walked past a tiny crack without thinking through the potential of a serious repair? If you choose to do nothing, one day you might regret it. I suggest that at the very least, temporarily seal that crack until gelcoat repair can be done. The most common areas that I see cracks that will cause moisture penetration is near the aft lazarette and on the cockpit seats where something heavy has hit the area with force. The most common cause is damage from the bottom fin of an outboard engine. 

If you have created a small crack, don't wish for the best, do something.

Bill
CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar


On Sun, Sep 20, 2020 at 7:41 PM Karen Smith via groups.io <karenharmonie=yahoo.com@groups.io> wrote:
Hello Amelians,

Here are our thoughts about this deck leak!

Any deck leak, no matter how small, in the main cabin of a Super Maramu is a serious issue that needs to be addressed RIGHT AWAY.  
This is the voice of painful experience. A TINY little salt line was all that alerted us to one of the biggest jobs we have had to do to our boat.

Here is why...

From the aft edge of the hatch in the main saloon forward, the deck is pretty standard balsa cored deck. 
Right behind the hatch, the deck surface rises about 3 inches, while the cabin ceiling height does not change. 
 
The cabin ceiling here is thin (4-6mm plywood) and there is an empty space between the cabin ceiling and the structural underside of the deck. 
If there is ANY leak into this space, the water is free to roll around, and will find a place to drip down probably quite remote from the actual source.

What makes this situation so serious, is the back edge of the balsa core on the forward deck is not sealed, and is exposed into this space. It will soak up that water, and rot.  This is a big expensive repair to do right.  

Leaks into this space can come from the traveler, but more likely is from the hatch in the main cabin.  

There is a hardwood frame around the hatch opening, and the hatch frame is screwed into this with wood screws.  
 A lot of force is applied to the screws that secure the hinge side of the frame.  
If one of these starts to leak, the wood saturates, and water is then deposited into that empty space between the sailing and the deck, and problems start. 

Karen Smith & Bill Kinney
SM #160
Annapolis, MD


Miles
 

Keren and Bill,

 

You were right.  The source of the leak is the screws holding the main deck hatch.  One screw was loose and it feels like the wood it is screwed into is rotted or at least saturated—not good.  It they will let me in, I will take the boat to Martinique next month.

 

This should be a word of warning to everyone.  If I had known about this possibility, it would have been easy to check on the screws periodically.

 

Many thanks for explaining it to me now so I know what to do.

 

Regards,

 

Miles

 

s/y Ladybug sm216, now in Newport, RI


Arno Luijten
 

Hi Bill,

Thanks for your wise words of advice. This is actually hitting on one my least favorite aspects of an Amel, the usage of balsa-wood in the deck core. This should have been abandoned in favor of Divinycell 30 years ago in my opinion.
For 54's a special word of advice: have a look at the point when the central stanchion sits in the rear railing/lifeline. It sits in this sort of cup that is bolted in the deck (it actually goes right through it). Amel fit this in with some caulking but (in my case) did not bother to protect the core material after drilling the hole.
In my case I had to remove the rotting core for about 10 cm diameter and fill the void with thickened epoxy. This also resolved a leak into the rear lazarette. Even great boat builders can drop a ball occasionally.

Regards,

Arno Luijten
SV Luna,
A54-121


Karen Smith
 

James,

”what has to be removed for inspection.”

I wish I had an easy answer for you on this one, unfortunately I do not. We discovered the problem when we had obvious core failure, so our “inspection” was peeling off the upper deck surface until we go to sound core.  Miles’ approach of pulling screws from the hatch frame and looking is I think as good as it gets.

There is a preventative that should be considered.  Remove the hatch and drill out the screw holes in the deck significantly larger than the diameter of the screw.  Drill down all the way through the wood piece.  Fill it with epoxy thickened with LOTS of high strength thickener.  Redrill a pilot hole for the screws, and again drill all the way through.  You want isolate the leak path from the wood, and you want to SEE a drip right away, not have it get trapped.  If you go this route, be prepared for surprises.  Not all the screws, and I bet not all the boats, are fixed in the same way!

Doing this is a bit fussy, requiring a bit of disassembly of the interior trim and for the hinge side screws it has to be done very carefully or else the screws will pull out in short order.  There are some other viable alternatives for resetting the screws, but pretty much all of them require pulling the hatch.

Bill Kinney


James Alton
 

Bill,

   Thanks so much for alerting me to this potential problem.  I will remove the hatch as you suggested and will seal the core at every deck penetration.  I will also use filled epoxy for this job just as you suggested.  I do normally try to preserve or restore the fibreglass for the top hole in such repairs which makes the process a bit more difficult but the idea is the same.   I have pulled the deck fills and most every deck penetration that I could find on our boat, removed the core and filled with epoxy.  So far I have not found any rotten core though the balsa was damp in the holes for the twist turns on the forward hatch locker lids,  not bad on a 33 year old boat!

James Alton
SV Sueno
Maramu #220

On Sep 21, 2020, at 8:38 PM, Karen Smith via groups.io <karenharmonie@...> wrote:

James,

”what has to be removed for inspection.”

I wish I had an easy answer for you on this one, unfortunately I do not. We discovered the problem when we had obvious core failure, so our “inspection” was peeling off the upper deck surface until we go to sound core.  Miles’ approach of pulling screws from the hatch frame and looking is I think as good as it gets.

There is a preventative that should be considered.  Remove the hatch and drill out the screw holes in the deck significantly larger than the diameter of the screw.  Drill down all the way through the wood piece.  Fill it with epoxy thickened with LOTS of high strength thickener.  Redrill a pilot hole for the screws, and again drill all the way through.  You want isolate the leak path from the wood, and you want to SEE a drip right away, not have it get trapped.  If you go this route, be prepared for surprises.  Not all the screws, and I bet not all the boats, are fixed in the same way!

Doing this is a bit fussy, requiring a bit of disassembly of the interior trim and for the hinge side screws it has to be done very carefully or else the screws will pull out in short order.  There are some other viable alternatives for resetting the screws, but pretty much all of them require pulling the hatch.

Bill Kinney


James Alton
 

A mid range  Divinycell (H80) has a compressive strength of about 174 PSI (http://www.fiberglasssupply.com/pdf/core/hmanm.pdf)

End grain balsa core has a compressive strength of around 1,837 PSI according to this site.(http://www.cstsales.com/end_grain_balsa.html)  Balsa does vary in density but this is a huge increase over any foam that I am aware of.  (http://www.cstsales.com/end_grain_balsa.html)

In general, polyester resins  create a fairly low secondary bond.  The balsa soaks up the resin so that the bond penetrates deep into the balsa and and this can create an exceptional bond, even with polyester if the layup is done properly.  It is best to float the balsa in resin before installing to keep the wood from sucking up too much resin leaving a dry joint.  With a foam like Dinvinycell the resin does not soak into the product, it pretty much sits on the surface.  If a core fails in it’s bond to the fibreglass layers or crushes from an applied load it is a structural integrity is compromised even if the foam itself is ok.  Divinycell seems to bond quite well to epoxies used in aircraft construction but most boats are built with Polyester resins.

So yes, one has got to take care in keeping water out of a balsa core but there are some really good reasons to use this material as a core material in my experience so I do not fault Amel at all for using it.  In fact so far I have not seen anything that I like better for core.

Best,

James
 

On Sep 21, 2020, at 6:29 PM, Arno Luijten <arno.luijten@...> wrote:

Hi Bill,

Thanks for your wise words of advice. This is actually hitting on one my least favorite aspects of an Amel, the usage of balsa-wood in the deck core. This should have been abandoned in favor of Divinycell 30 years ago in my opinion.
For 54's a special word of advice: have a look at the point when the central stanchion sits in the rear railing/lifeline. It sits in this sort of cup that is bolted in the deck (it actually goes right through it). Amel fit this in with some caulking but (in my case) did not bother to protect the core material after drilling the hole.
In my case I had to remove the rotting core for about 10 cm diameter and fill the void with thickened epoxy. This also resolved a leak into the rear lazarette. Even great boat builders can drop a ball occasionally.

Regards,

Arno Luijten
SV Luna,
A54-121


James Alton
 

Bill,

   I am glad that you pointed out the concern of leakage into the core from cracks as this does happen.  Not all cracks are the same, some are a concern and some aren’t and telling the difference is sometimes difficult.  Here are a  couple general things that I have learned.

1.  Cracks that occur near a high load areas where hardware is attached usually extend into the glass laminate.  

2.  Cracks that form on an open deck area such as what we commonly see in the simulated teak decks should only be in the gelcoat so there is no path for water to leak into the core.

3.  You can get some idea of whether a particular crack is serious by how much displacement there is on the surface.  Is the top of the crack level or is one edge raised?  If level, odds are pretty good that the laminate is still ok.  If you can catch your fingernail on a raised edge, the crack likely extends into the laminate at least some.  

3.  Your advice to fix damage caused by dropping something heavy and fracturing the glass laminate is really good advice.  An amazing amount of water can enter through even a small crack or hole over time and it is a one way trip since it is pretty much impossible to remove short of using vacuum pump.  

James 





   

On Sep 21, 2020, at 10:09 AM, CW Bill Rouse <brouse@...> wrote:

Bill & Karen and everyone,

I love your sketch and simple explanation of potentially a serious issue. I will add a word of caution. Small cracks in the gelcoat of any Amel can possibly lead to a serious core moisture problem. 

How many of us have walked past a tiny crack without thinking through the potential of a serious repair? If you choose to do nothing, one day you might regret it. I suggest that at the very least, temporarily seal that crack until gelcoat repair can be done. The most common areas that I see cracks that will cause moisture penetration is near the aft lazarette and on the cockpit seats where something heavy has hit the area with force. The most common cause is damage from the bottom fin of an outboard engine. 

If you have created a small crack, don't wish for the best, do something.

Bill
CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar


On Sun, Sep 20, 2020 at 7:41 PM Karen Smith via groups.io <karenharmonie=yahoo.com@groups.io> wrote:
Hello Amelians,

Here are our thoughts about this deck leak!

Any deck leak, no matter how small, in the main cabin of a Super Maramu is a serious issue that needs to be addressed RIGHT AWAY.  
This is the voice of painful experience. A TINY little salt line was all that alerted us to one of the biggest jobs we have had to do to our boat.

Here is why...

From the aft edge of the hatch in the main saloon forward, the deck is pretty standard balsa cored deck. 
Right behind the hatch, the deck surface rises about 3 inches, while the cabin ceiling height does not change. 
 
The cabin ceiling here is thin (4-6mm plywood) and there is an empty space between the cabin ceiling and the structural underside of the deck. 
If there is ANY leak into this space, the water is free to roll around, and will find a place to drip down probably quite remote from the actual source.

What makes this situation so serious, is the back edge of the balsa core on the forward deck is not sealed, and is exposed into this space. It will soak up that water, and rot.  This is a big expensive repair to do right.  

Leaks into this space can come from the traveler, but more likely is from the hatch in the main cabin.  

There is a hardwood frame around the hatch opening, and the hatch frame is screwed into this with wood screws.  
 A lot of force is applied to the screws that secure the hinge side of the frame.  
If one of these starts to leak, the wood saturates, and water is then deposited into that empty space between the sailing and the deck, and problems start. 

Karen Smith & Bill Kinney
SM #160
Annapolis, MD





Arno Luijten
 

Hi James,

I'm aware of the differences between balsa and Divinycell, particularly the difference in adhesion to polyester. However Hallberg Rassy and many others have been using Divinycell since the eighties and correct me if I'm wrong, I've never heard of a soggy deck on a Halberg-Rassy. I used to own a 1992 model and the deck was solid, even with the gazillion holes because of the teak deck. Not that I would ever want a teak laid boat anymore, but that is another story. My previous boat had no teak deck but did carry a Divinycell cored deck and hull (above the waterline). Not a single problem manifested itself. I sold her when she was 16 years old.
The compression strength is something you can take into account when doing the structural calculations on the boat and should not be a problem.

So although there are some advantages to balsa I find it a poor choice for cored decks simply because water-ingress can be very hard to spot/monitor until it's at an advances state. There is a YouTube channel (Sail Life) that can illustrate the crazy amount of work it can be to rectify the problem once the balsa starts rotting.

Regards,

Arno Luijten
SV Luna,
A54-121


James Alton
 

Arno,. You are correct, the Divinycell won't rot if water gets in. For a boat with a teak deck that has fastener holes I would prefer the Divinycell since with that many holes water is going to get in.  I have been in the boat repair business for more than 40 years and I have dug out a lot of rotten plywood and balsa core and you are correct it is a huge nasty job to do right.  The Amel design thankfully has very few deck and cabin penetrations so it is not that big of a job to decore each and every hole, fill with epoxy, redrill and seal.  From that point forward if a fastener leaks the water cannot get into the core.  The increase in compressive strength of the balsa will create a more Ridgid structure and the increase in the bonding to the fiberglass skins (assuming the layup was done correctly) also adds strength.  So this means that with a weaker core you probably need to to build the boat a bit heavier to have the same strength.  Are the HR's heavier than a comparable Amel?  I have worked with the Divinycell on sailplanes and I will say that it the the best foam type core that I have worked with.  Some of the planes were 20 plus years old and the core was still healthy.  I have seen many other types of foam used for core material break down.   So to distill yes on a boat where I feel that I can keep the core dry, I would much prefer to have balsa core such as my Amel.  On a boat where there is a high probability of water intrusion such as a deck or cabin with a lot of screw holes, a non organic core such as Divinycell would be preferable.  Best to you.  

James Alton
SV Sueno
Maramu #220

On Sep 21, 2020 11:49 PM, Arno Luijten <arno.luijten@...> wrote:
Hi James,

I'm aware of the differences between balsa and Divinycell, particularly the difference in adhesion to polyester. However Hallberg Rassy and many others have been using Divinycell since the eighties and correct me if I'm wrong, I've never heard of a soggy deck on a Halberg-Rassy. I used to own a 1992 model and the deck was solid, even with the gazillion holes because of the teak deck. Not that I would ever want a teak laid boat anymore, but that is another story. My previous boat had no teak deck but did carry a Divinycell cored deck and hull (above the waterline). Not a single problem manifested itself. I sold her when she was 16 years old.
The compression strength is something you can take into account when doing the structural calculations on the boat and should not be a problem.

So although there are some advantages to balsa I find it a poor choice for cored decks simply because water-ingress can be very hard to spot/monitor until it's at an advances state. There is a YouTube channel (Sail Life) that can illustrate the crazy amount of work it can be to rectify the problem once the balsa starts rotting.

Regards,

Arno Luijten
SV Luna,
A54-121