Leak from freshwater tank - woodcore epoxy boat

[geem]

Looks like the tank is under the armchair, or perhaps under the whole structure into which the armchair is set.
I would concur with the opinions expressed above regarding replacing the built-in tank with a plastic or s/s alternative.

But that makes little sense. A simple bit of epoxy and glass work will have the tank back in full working order for very little money. Removing everything to fit a new tank is a massive job. The existing tank may well have some structural roll in the boat. Modifying all of this at great expense compared to a simple repair is a no brainer for me

 

[Blueboatman]

I would concur with Tranona and Concerto I’m afraid .
Worth contacting the builder initially for another opinion
Three part problem perhaps ?
1 dry the wood= saves the boat
2 Repair in situ from within ’ somehow’
3 Get the fein tool out and get dismantling the joinery in order to …. create a flanged tank on a thoroughly reglassed tank with integrity between sides and top , or a drop in replacement tank, material tbd.


Initially , if it were my boat and say it was afloat and I wanted to go sailing (hint hint ) I would simply strip back the veneer coatings on both sides of the bulkhead and get it dry
Best luck with it , lovely boat.

 

[KompetentKrew]

These replies are rather depressing. I am presently working my way through stages of denial.

I don't see that a drop-in tank is a possibility as the armchair sits in a cut-out that is smaller than the top of the tank - this is somewhat visible if you look at this image or this one or this one.

Consequently it is not possible to put a rigid tank in place here - not without it being substantially smaller; I'd guess only a quarter or a third of the capacity.

It would be possible to cut out the top of the tank using a multitool and then replace with a flexible tank, or just use the space as storage and then put a replacement tank under the couch on the opposite side of the boat.

So far I like @geem's suggestion best, but I have no experience of fibreglass so I'd have to pay someone to undertake the work, and I daresay this would turn out expensive.

 

[geem]

These replies are rather depressing. I am presently working my way through stages of denial.

I don't see that a drop-in tank is a possibility as the armchair sits in a cut-out that is smaller than the top of the tank - this is somewhat visible if you look at this image or this one or this one.

Consequently it is not possible to put a rigid tank in place here - not without it being substantially smaller; I'd guess only a quarter or a third of the capacity.

It would be possible to cut out the top of the tank using a multitool and then replace with a flexible tank, or just use the space as storage and then put a replacement tank under the couch on the opposite side of the boat.

So far I like @geem's suggestion best, but I have no experience of fibreglass so I'd have to pay someone to undertake the work, and I daresay this would turn out expensive.

Fibreglass work really isn't difficult. If you can get a copy of the West book on fibreglass you will be able to do the job yourself. Its a great skill to have. If you have a local boat builder you might be able to get some lessons. My wife is excellent at glass work. We do most of our grp stuff together. One person with gloves on doing the sticky bit, the other with clean hands doing the pass and fetch

 

[KompetentKrew]

I'm sure that fibreglassing, or learning it, is generally within my abilities, but this feels like a job which is too big and major to start learning with.

 

[penfold]

I'm sure that fibreglassing, or learning it, is generally within my abilities, but this feels like a job which is too big and major to start learning with.

A flexible tank in the tank void will offer 70-80% of the capacity and allow you to go sailing quickest and with least faff.

 

[geem]

I'm sure that fibreglassing, or learning it, is generally within my abilities, but this feels like a job which is too big and major to start learning with.

Cut the access hole. This will allow you to get in. Grind off any paint on the crack at about 3" either side of the crack until you have bare fibreglass. Cut out pieces of glass, (say 300g/m2) about 10 layers. To cover the crack. You will need a serated roller to push the resin through the glass. The West book will tell you how to do this. Making the lid is super simple. If you can get a piece of this float glass to lay on a work bench, you just wax it and lay the glass up to the required thickness, about 10mm. Once you have the glass laid up you cut the glass to the circular shape of your lid with a jig saw. Glass M10 bolts in from the inside like the picture I posted. You might find you enjoy the project

 

[Tranona]

Cut the access hole. This will allow you to get in. Grind off any paint on the crack at about 3" either side of the crack until you have bare fibreglass. Cut out pieces of glass, (say 300g/m2) about 10 layers. To cover the crack. You will need a serated roller to push the resin through the glass. The West book will tell you how to do this. Making the lid is super simple. If you can get a piece of this float glass to lay on a work bench, you just wax it and lay the glass up to the required thickness, about 10mm. Once you have the glass laid up you cut the glass to the circular shape of your lid with a jig saw. Glass M10 bolts in from the inside like the picture I posted. You might find you enjoy the project

I would agree with this approach IF it were a GRP boat, but it is not. It is wood epoxy and the way that crack appears and the areas of sealing ring alarm bells. The transverse bulkhead is structural and is bonded to the hull which is epoxy encapsulated wood. Water penetration is sufficient to show through on the other side so will be in the inner veneer and may well have got into the hull core (the ply bulkhead is tabbed to the hull). Have a look at John's photo in post#11 as an extreme example of what happens when water gets into a wood core. Not suggesting anything like that as the hull is sheathed internally, but the weak point is where interior furniture and bulkheads are bonded to the hull before the interior is sheathed.

I am reminded of this just today speaking to the current owner of a sheathed GH that I tried to buy a couple of years ago. Well maintained owned for 20+years and seller confident it was sound. We discovered rot in 2 bulkheads along the line where they met the hull and in one case it had got into the hull. Everything looked fine from outside and it was a combination of running a moisture meter down the line of the bulkheads that first raised concern followed by a tap test. The survey report was enough for me to withdraw. The seller subsequently had the boat repaired under the supervision of the surveyor.

The point I am trying to get across is that before any repair is contemplated there needs to be a thorough investigation to determine the extent (if any) of water penetration into the structure. My gut feeling based on the photos is that the cracking is far more extensive and at the very least the top of the tank including the base of the seats needs removing so that the whole of the joint between the furniture, bulkhead and hull can be inspected and opened up. I can see the repair much as you describe, epoxy glass tape along the seams and the top refitted. There may well be other equally effective ways to repair but the key thing now is to establish the full extent of the damage as not dealing with that now will have long term consequences.

 

[Refueler]

But that makes little sense. A simple bit of epoxy and glass work will have the tank back in full working order for very little money. Removing everything to fit a new tank is a massive job. The existing tank may well have some structural roll in the boat. Modifying all of this at great expense compared to a simple repair is a no brainer for me

I'm playing through my head and lets see ...

We both agree that top should be cut ... you advise large enough to be able to work resin and glass .... I say to be able to drop in new tank.

mmmmmmm To do the resin and glass work - surely you would need a massive opening as the work is at TOP joint and not easily seen. If it was bottom joint - then I agree.

The only real work if a new tank is slotted in - is to clean up the edges of old top ... and replumb the fittings. A new top could be simply a decent marine ply sheet screwed down - allowing good access at any time for maintenance.

mmmmm I think cut out top ... new tank and replumb ....

 

[penfold]

Without knowing if the tank is structural none of that is simple; if they are structural the top and the baffle cannot be removed, which is where bag tanks come in, they would fit into the existing space.

 

[Refueler]

I would agree with this approach IF it were a GRP boat, but it is not. It is wood epoxy and the way that crack appears and the areas of sealing ring alarm bells. The transverse bulkhead is structural and is bonded to the hull which is epoxy encapsulated wood. Water penetration is sufficient to show through on the other side so will be in the inner veneer and may well have got into the hull core (the ply bulkhead is tabbed to the hull). Have a look at John's photo in post#11 as an extreme example of what happens when water gets into a wood core. Not suggesting anything like that as the hull is sheathed internally, but the weak point is where interior furniture and bulkheads are bonded to the hull before the interior is sheathed.

I am reminded of this just today speaking to the current owner of a sheathed GH that I tried to buy a couple of years ago. Well maintained owned for 20+years and seller confident it was sound. We discovered rot in 2 bulkheads along the line where they met the hull and in one case it had got into the hull. Everything looked fine from outside and it was a combination of running a moisture meter down the line of the bulkheads that first raised concern followed by a tap test. The survey report was enough for me to withdraw. The seller subsequently had the boat repaired under the supervision of the surveyor.

The point I am trying to get across is that before any repair is contemplated there needs to be a thorough investigation to determine the extent (if any) of water penetration into the structure. My gut feeling based on the photos is that the cracking is far more extensive and at the very least the top of the tank including the base of the seats needs removing so that the whole of the joint between the furniture, bulkhead and hull can be inspected and opened up. I can see the repair much as you describe, epoxy glass tape along the seams and the top refitted. There may well be other equally effective ways to repair but the key thing now is to establish the full extent of the damage as not dealing with that now will have long term consequences.

I often have issues with Tranona posts - but this one is bang on point. Just glassing up the crack is probably just a 'bandaid' and the real problem will just carry on. Once water has got behind the resin layer - it will continue invading the ply core and who knows what further damage will occur. I bet if I was to run my Protimeter around the area ... the meter would be all over the shop ... indicating far more than just the stained area.

I think OP is over-reacting to the idea of cutting out tank top. Complete removal of tank top would in my mind be the way forward - then every aspect of the problem can be checked.... and remedied .... even if so wished - glassing up the original tank and fitting new tank top.

I realise this is a daunting project ... but that's boating !!

 

[Tranona]

Just to add a bit more - why did the joint crack in the first place? Seems odd as from the photos it does not seem to be a high load area. As suggested earlier probably worth talking to the designer/builder.

 

[Refueler]

Just to add a bit more - why did the joint crack in the first place? Seems odd as from the photos it does not seem to be a high load area. As suggested earlier probably worth talking to the designer/builder.

You and I know - that all boats flex regardless of construction .... then along comes someone who decides to add a bit of furniture or item ... roll on a few years and start to see effects ....

????

Having inspected many boats over many years before I left UK .... I generally found boats of the 'not new' category had replaced built in tanks (fuel or water) with 'drop in' replacements .... often into the old tank.

 

[geem]

A flexible tank in the tank void will offer 70-80% of the capacity and allow you to go sailing quickest and with least faff.

Not my experience. The flexible tank can be a constant source of irritation. Leaks

I would agree with this approach IF it were a GRP boat, but it is not. It is wood epoxy and the way that crack appears and the areas of sealing ring alarm bells. The transverse bulkhead is structural and is bonded to the hull which is epoxy encapsulated wood. Water penetration is sufficient to show through on the other side so will be in the inner veneer and may well have got into the hull core (the ply bulkhead is tabbed to the hull). Have a look at John's photo in post#11 as an extreme example of what happens when water gets into a wood core. Not suggesting anything like that as the hull is sheathed internally, but the weak point is where interior furniture and bulkheads are bonded to the hull before the interior is sheathed.

I am reminded of this just today speaking to the current owner of a sheathed GH that I tried to buy a couple of years ago. Well maintained owned for 20+years and seller confident it was sound. We discovered rot in 2 bulkheads along the line where they met the hull and in one case it had got into the hull. Everything looked fine from outside and it was a combination of running a moisture meter down the line of the bulkheads that first raised concern followed by a tap test. The survey report was enough for me to withdraw. The seller subsequently had the boat repaired under the supervision of the surveyor.

The point I am trying to get across is that before any repair is contemplated there needs to be a thorough investigation to determine the extent (if any) of water penetration into the structure. My gut feeling based on the photos is that the cracking is far more extensive and at the very least the top of the tank including the base of the seats needs removing so that the whole of the joint between the furniture, bulkhead and hull can be inspected and opened up. I can see the repair much as you describe, epoxy glass tape along the seams and the top refitted. There may well be other equally effective ways to repair but the key thing now is to establish the full extent of the damage as not dealing with that now will have long term consequences.
[/QUOTE
From the photos it looks like strip construction. Red cedar strip planking is built is around temporarily frames. The sheathed wood is glassed before bulkheads are installed so the sheathed wood is not connected to internal structure. The normal wood core is red cedar. Incredibly resistant to rot and moisture penetration. This is why it is chosen for this kind of construction. You are right that investigation in to how far any water has gotten in to the bulkhead is sensible but if the boat has been constructed properly the cedar planking won't be a concern. Your GH was built in a very different way. Buiding in ply with bulkheads installed then sheathing is an inferior technique where moisture could certainly get to the hull plywood.

 

[Tranona]

I know the difference between the methods of construction. The commonality is in sheathing and the problems that arise when water gets through the sheathing into the core - whether it be cedar or ply. I refer you back to post#11. That is cedar strip core that has rotted inside the sheathing. Cedar is relatively rot resistant but hulls are sheathed in and out to keep it dry. The interior may have been fully sheathed before the bulkheads were bonded in but it is difficult to tell from the photos because they are of the inside of the tank which seems to have then been sheathed to cover the ply bulkhead as well.

 

[geem]

I know the difference between the methods of construction. The commonality is in sheathing and the problems that arise when water gets through the sheathing into the core - whether it be cedar or ply. I refer you back to post#11. That is cedar strip core that has rotted inside the sheathing. Cedar is relatively rot resistant but hulls are sheathed in and out to keep it dry. The interior may have been fully sheathed before the bulkheads were bonded in but it is difficult to tell from the photos because they are of the inside of the tank which seems to have then been sheathed to cover the ply bulkhead as well.

The method of construction is to fully sheath before bulkheads are installed. It should not be in doubt

 

[KompetentKrew]

Without knowing if the tank is structural none of that is simple; if they are structural the top and the baffle cannot be removed, which is where bag tanks come in, they would fit into the existing space.

I don't believe it is structural. The bulkhead at the stern of the tank is, but I don't believe the top or sides are. I don't say this definitively, just my feeling.

The bulkhead at the rear of the tank, with the staining on it and which forms the front of the chart table, is behind the gentleman's blue shirt in this image. I have marked in red the location of the tank in this image.

I think OP is over-reacting to the idea of cutting out tank top. Complete removal of tank top would in my mind be the way forward - then every aspect of the problem can be checked.... and remedied .... even if so wished - glassing up the original tank and fitting new tank top.

I realise this is a daunting project ... but that's boating !!

It's not cutting the top out that I find daunting, but the rest of the repair!

I'm honestly a bit overwhelmed right now, and a few things have gone wrong the last couple of weeks (after they had been going so well too!) so I'm just going to take it easy for a while - explore what I can see of the crack some more soon, see if I can get in touch with Johan Vels, just do some other jobs and ponder this.

As I said before, I can't remove the whole of the top of the tank because the tank is larger than the cut-out for the armchair. I could cut a new inspection hole nearly as large as the base of the armchair, so close to 50cm x 50cm or 50cm diameter.

Circled in blue in this image is the existing inspection hatch, which is seen open in this earlier image and which is similar to this design. It would be impossible to fit a TekTank or stainless steel one through the cut-out for the armchair, so I would be better off cutting off the top completely, using this space for storage instead of a tank, and then putting in a new tank on the other side of the boat. But that would be a big job too, so I'll just keep pondering some more and hopefully I'll have a flash of inspiration when I'm not expecting it.

I can see a compelling argument for a flexible tank (although I don't really like them) but I'm not sure I'd be able to get one in a suitable shape.