Spongy boat decks

[doug748]

Here is an interesting bit of video, testing some short cut methods for fixing this problem:

A growing problem that could well be improved, if not totally fixed, fairly simply.

.

 

[thinwater]

I did something similar for Practical Sailor years ago, with similar results.

• When injecting polyurethane (Gorilla Glue), if you plug the holes with temprary dowels or similar, the pressure of the foam forces the glue further.
• Like the above video, I ripped the deck off on the next several projects. Injecting glue into mulch is not much of a fix.

I will admit to injecting glue after a propper repair once, when tapping indicated that a small area somehow didn't bond just right. The difference is that everything was dry, it was only one small spot, and I was only filling an air pocket. Very different.

 

[doug748]

• Like the above video, I ripped the deck off on the next several projects. Injecting glue into mulch is not much of a fix.

What I took from the video is that injecting resin can be a good fix, in certain circumstances.

 

[Trident]

I had an area like this on my Prout cat. I cut out the ceiling inside (so as not to have to repair the antiskid deck) cut out / scraped out a couple of square feet of black soggy balsa , epoxied in foam core and epoxied the ceiling back on and made an invisible repair in the ceiling ...

only to be told afterwards, that Prout originally used solid decks, and when cored decks became popular , they added balsa and thin GRP layer to the bottom of their existing deck moulds to be able to say they had cored decks but the scantlings for the original solid decks were more than strong enough so I could have left it as was with no structural ill effects

 

[thinwater]

What I took from the video is that injecting resin can be a good fix, in certain circumstances.

I once grew a houseplant in some rotten core that I removed. It did quite well. It was really very much like potting mulch.



It can be an adequate half-assed repair in some cases. The bond and stiffness won't last because the rot and the balsa the epoxy is bonding will turn to mulch. You just filled some gaps, and when the core around the epoxy rots you are back where you started, with some loose epoxy lumps in the core.

 

[doug748]

Adequate, half arsed repairs are just the ticket with old boats.

 

[steve yates]

If the deck is spongy the core has already delaminated ( probably because its rotted away to mulch) so not much point in injecting epoxy into a load of holes, it solves nothing. Cut the top skin off and replace it properly. Or cut the bottom if you are either highly skilled or a masochist, its no job for an amateur bodger whereas the top is pretty simple.
Saying that, I haven’t watched this vid yet, I will when I have time. I have watched a lot of others and nothing I’ve seen has ever convinced me the injection method is just a load of wishful thinking.
From the same stable the recommendation for decoring by using a bent nail in a drill,
I doubt anyone who says this has ever tried it in anger, it’s a load of crap. Get a dremel and a suitable bit and the job becomes simple. Even better, spend some more and get the flexible extension and it would be even easier.

 

[Blueboatman]

I once grew a houseplant in some rotten core that I removed. It did quite well. It was really very much like potting mulch.

View attachment 200974

It can be an adequate half-assed repair in some cases. The bond and stiffness won't last because the rot and the balsa the epoxy is bonding will turn to mulch. You just filled some gaps, and when the core around the epoxy rots you are back where you started, with some loose epoxy lumps in the core.

I loved reading Practical Sailor magazine

This method here intrigued me whilst at the same time seemed as crazy as a crazy thing can be . For entertainment only I caption it: Using Microwaves to Dry a Wet Deck Core - Cruisers & Sailing Forums

I’ve repaired a smallish bit of cockpit sole in an old US boat I owned but meh it all seemed very crude . Cut n shut, grinding bevels , balsa sheet, holes, epoxy, syringes, fairing, faking non skid , tap tap, fingers crossed

 

[doug748]

If the deck is spongy the core has already delaminated ( probably because its rotted away to mulch) so not much point in injecting epoxy into a load of holes, it solves nothing. Cut the top skin off and replace it properly. Or cut the bottom if you are either highly skilled or a masochist, its no job for an amateur bodger whereas the top is pretty simple.
Saying that, I haven’t watched this vid yet, I will when I have time. I have watched a lot of others and nothing I’ve seen has ever convinced me the injection method is just a load of wishful thinking.
From the same stable the recommendation for decoring by using a bent nail in a drill,
I doubt anyone who says this has ever tried it in anger, it’s a load of crap. Get a dremel and a suitable bit and the job becomes simple. Even better, spend some more and get the flexible extension and it would be even easier.

The method works excellently in the video. The problem is twofold:

1) He is working with very small samples, in an easily controlled, clean, dry environment.
2) The samples were not saturated as they could well be in the field.

Still, if you have a squeaky deck with marginal problems you may not need a totally convincing improvement to make the repair very useful.
I suspect the essence is getting enough epoxy into the deck to be happy that the voids are acceptably bridged, in which case the improvement may well endure, even if (as is highly likely) the internal bonds are weak or even non existent.

.

 

[steve yates]

Mmm, I’m not convinced. Apart from the fact it does nothing about the soaking wet mulch and damp core still there, which will continue to wick throughout the balsa core along the whole deck; as soon as any surveyor pits a moisture meter over the deck it will go off the scale. And if the boat was being kept forever so any future sale wasn’t an issue, then it’s even more important to deal with the rotten core properly, before the problem spreads.
I can live with levels of moisture in the deck of an old boat, but as soon as the bond starts to go I think it’s time to sort it or get rid of it.
Compared to removing and cleaning up westerly droop, sorting it is a walk in the park

 

[ducked]

I would use a hole saw

I would make an array of holes close enough to each other that I could remove the compromised core material between them by whatever means. This might involve a bit of SWR in a power drill

Once the compost was clear I would spray acetone or ethanol in to surface dry the void area and its perimeter, then I would let it dry some more applying heat, airflow from a fan, possibly a vacuum if I could arrange it, and maybe microwaves, as above.

Once it seemed to be dry I would cut a lot of filler disks of...er...something, (maybe foam, fibreglass, polythene, possibly oak. ,microwave seasoned, but absolutely NOT F-ing BALSA) that would fit through the holesaw holes.

Then I would butter them up with...er...something. (I suppose epoxy filler would be expected, but I would probably use concrete with a lightweight aggregate if it was a big volume) and pack them in firmly via the holes, filling the gap between the deck layers with them. If the edges of the disks were sharp and they were fairly thin they should interleave a bit, keying the structure

Then I'd glue the deck disks back on and go for a celebratory drink

But I probably never will, because I believe my boat doesn't have a cored deck.

 

[thinwater]

... Or cut the bottom if you are either highly skilled or a masochist, its no job for an amateur bodger whereas the top is pretty simple....

Actually, it's not bad and possibly simpler (I've done both way several times each), with a few rules and exceptions:

• Interior damaged area clear of bulkheads. If it crosses a bulkhead, do it from the top.
• The liner must be dead simple to take off and put back. Carpet is dead simple, some others not so much.
• Not your first fiberglass job. Not bad, but not your first and probably not your tenth. All the standard rules and methods should be commonplace to you.
• Cover EVERYTHING and put an exhaust fan in the bow hatch.
• Have a helper to hand you stuff. Because of the more confined space, moving around to mix, cut glass, and apply is hard. OK if very small area.
• Pre-cut glass and core to the extent practical. Very helpful in tight spaces.
• Pre-butter the core on a PE work board and roll into place. Keep the pieces no more than ~ 12" square; bigger is not stronger. Little fill-in bits are fine (same on deck). The butter must be thick enough for it to stick. And roll into place. Let it kick.
• Pre-wet the glass about 2 layers at a time (1708 biax is good), no bigger than 6" x 12". What you can manage overhead. Overlap them 1.5 inches. Bigger pieces are not stronger, just harder to work with. Fill in sections are fine as long as they overlap. 6-oz. finish cloth as a last layer can make it smoother and hide all the laps, but not needed if covered. Roll in place. brush a little epoxy on the edges only to smooth down. Do NOT apply epoxy to the glass overhead; this is the nightmare Steve was talking about. Two layers of 1708 is probably all you need on the inside.
• If you need more glass, let the prior layer gel a little first so that it does not come down. Not cured, just past the working time.
• Roll everything. This makes the bond and bring excess epoxy up. For example, you can probably add a last layer or finish glass without any wetting, just using the epoxy that came up.
• Wipe off the amine blush (water) before reattaching the carpet with spray contact cement.
• Wipe the cabin down with vinegar. You smeared some epoxy somewhere, you know you did, and this will take it off. But keep it away from what you just did (inhibits cure). Good tip on deck too.

I really comes down to the geometry. Which is easier to access and which is easier to refinish. The tricks are pre-wetting just right so that everything sticks, and keeping the sections small. If you are going to paint the boat anyway, top side is easier.

 

[Refueler]

Went to view a Nauticat with idea to renovate ... price was 1/2 what a similar age in commission would be.

First sight - the foredeck and part of side decks looked strange ... not very smooth .. no teak ... just bumpy GRP. Seller admitted that deck had been repaired as it was 'spongy' ... injecting of resins ... then new GRP layer over top ...

I took out my two moisture meters ... Protimeter (for reall high levels of moisture) and the Tramex Skipper for very low levels ...

The Tramex just went crazy as I expected even on its lowest sensitivity .... the Protimeter went straight to max as well ..

The deck felt strange when walked on ... as though it was slightly moving as you walked ..

Guy admitted that he had tried injecting resin ... and resorted to adding a layer of GRP deck to try and solve it once the injection proved useless.

Obviously I walked away ... about 6 months later - I saw it advertised again - same seller but price seriously reduced ... to not much more than the engines worth.

I pity whoever may get suckered into buying it ... and such a shame for such a great boat design.

 

[reallycoliholic]

A related point but please bear with me this may take a minute to get to the relevant part.

I bought a house in France in 2006 and there was an existing massive large crack in the corner of a wall resulting in subsidence of the brick corner. The crack was big enough that you could put a finger right through to the outside (solid wall no cavity). This was subject of an insurance claim by the vendor's insurers and work to rectify it was due to be done within a month of completing the purchase.

A month or so later a company turned up to carry out the repair and they drilled 5mm holes all over the floor about every 30cm and then injected some "epoxy" under pressure that jacked up the whole floor to such an extent that the gap in the brickwork totally closed up. I looked on their website at the time, sorry I can't remember their name but they were based in St Nazaire, and their website showed them doing similar jacking up to a 3 storey office block by two feet.

Point being the "epoxy" was totally controllable and I would think would be excellent fix to the deck in the OP.

I'll see if I can find out who they are but I'd guess fairly easily findable if you ask auntie Google

 

[ducked]

Went to view a Nauticat with idea to renovate ... price was 1/2 what a similar age in commission would be.

First sight - the foredeck and part of side decks looked strange ... not very smooth .. no teak ... just bumpy GRP. Seller admitted that deck had been repaired as it was 'spongy' ... injecting of resins ... then new GRP layer over top ...

I took out my two moisture meters ... Protimeter (for reall high levels of moisture) and the Tramex Skipper for very low levels ...

The Tramex just went crazy as I expected even on its lowest sensitivity .... the Protimeter went straight to max as well ..

The deck felt strange when walked on ... as though it was slightly moving as you walked ..

Guy admitted that he had tried injecting resin ... and resorted to adding a layer of GRP deck to try and solve it once the injection proved useless.

Obviously I walked away ... about 6 months later - I saw it advertised again - same seller but price seriously reduced ... to not much more than the engines worth.

I pity whoever may get suckered into buying it ... and such a shame for such a great boat design.

Well, apparently not a great boat design WRT its decks.

Could still be an OK buy though if cheap enough, though probably harder to fix now than if they hadn't tried

 

[Fr J Hackett]

A deck repair can be done by an amateur, there was a series of videos by a Swedish guy completely rebuilding an old 40 foot Warrior. He replaced the entire rotten core in the deck with closed cell foam. A significant undertaking.

 

[Refueler]

A related point but please bear with me this may take a minute to get to the relevant part.

I bought a house in France in 2006 and there was an existing massive large crack in the corner of a wall resulting in subsidence of the brick corner. The crack was big enough that you could put a finger right through to the outside (solid wall no cavity). This was subject of an insurance claim by the vendor's insurers and work to rectify it was due to be done within a month of completing the purchase.

A month or so later a company turned up to carry out the repair and they drilled 5mm holes all over the floor about every 30cm and then injected some "epoxy" under pressure that jacked up the whole floor to such an extent that the gap in the brickwork totally closed up. I looked on their website at the time, sorry I can't remember their name but they were based in St Nazaire, and their website showed them doing similar jacking up to a 3 storey office block by two feet.

Point being the "epoxy" was totally controllable and I would think would be excellent fix to the deck in the OP.

I'll see if I can find out who they are but I'd guess fairly easily findable if you ask auntie Google

I am renovating the old Court House in Ventspils .... bought it for conversion into apartments.

Unfortunately I was in Hospital when inspection was made to decide purchase. All was reported good and I signed off the money .... paperwork etc.

Your čorner subsidence'echoes what Inspection failed to pick up on ...

Being just in from the river bank in the port ... the foundations are šoft'and needed substantial stones and rock creation ... over the ensuing hundred and fifty odd years .. the wall nearest river has subsided. Seller was fully aware of this having had a survey done about 7 years ago. I told Inspectors / junior partner to request ALL surveys / Inspections conducted from previous ownership / Court days etc ....

Now I have serious situation that Building Regs because its Historical Building will mean expensive works specifically detailed by Historical Dept.

 

[Fr J Hackett]

I am renovating the old Court House in Ventspils .... bought it for conversion into apartments.

Unfortunately I was in Hospital when inspection was made to decide purchase. All was reported good and I signed off the money .... paperwork etc.

Your čorner subsidence'echoes what Inspection failed to pick up on ...

Being just in from the river bank in the port ... the foundations are šoft'and needed substantial stones and rock creation ... over the ensuing hundred and fifty odd years .. the wall nearest river has subsided. Seller was fully aware of this having had a survey done about 7 years ago. I told Inspectors / junior partner to request ALL surveys / Inspections conducted from previous ownership / Court days etc ....

Now I have serious situation that Building Regs because its Historical Building will mean expensive works specifically detailed by Historical Dept.

If you have written proof of the request then you have a case against the inspection company. If you don't the request was never made ( it may well have been but doesn't exist)

 

[Refueler]

Well, apparently not a great boat design WRT its decks.

Could still be an OK buy though if cheap enough, though probably harder to fix now than if they hadn't tried

In fact a great boat - but when neglected and allowed to suffer - what do you expect ?

Seller had bought in Sweden - motored it to Latvia - cabins were in shambles where previous had tried to renivate .. must have been one hell of a trip !
Obviously he planned to renovate - but found the amount needed to be well outside the scope of DIY.

 

[Refueler]

If you have written proof of the request then you have a case against the inspection company. If you don't the request was never made ( it may well have been but doesn't exist)

In Hospital ... with half my face not working ... I was concerned with my health ... everything was verbal.

Junior partner offered to buy out my majority in the project - but by then I had already sunk in a large amount that they could never cover ...

We basically came to agreement that we were both at fault .. their failure to ask / inspect properly ... my failure to not press the matters harder and in writing.

Luckily projected valuation after if all completed will be greater than the investment made. The building sits in the old Hanseatic Town ... with all the restaurants / amenities / castle / river etc.