Need help with soft deck

Hello! Excited to be part of this group. My parents passed and I’m fortunate to now own their 1984 present trawler 42 feet. I’ve moved the boat from Florida to Portlnd, Oregon. I’m having a problem, which keeps me awake at night, with a soft/spongy deck. I can access with difficulty the under side of the deck from inside cabinets. Is it better/easier to fix the rotten wood from the to top part of the deck or go through the bottom? Love any advice. Much thanks.

Condolences on you loss, hopefully this boat will be a pleasant reminder of them.

Going at the deck from the top is daunting but is the quickest and most straight forward aproach. Fiberglassing upside down is a huge challenge and not worth the trouble of attempting unless the finish of the deck is perfect which I doubt it is. Take some pics of the area of damage.

Welcome aboard. Also sorry for your loss. I am assuming that the decks are fiberglass with a soft and wet core. The best way also the easiest way is to go from the top. If it is a large area then make sure to support the deck from below before starting. Find out how large an area you need to repair. If it is large you may want to do it in sections. Cut the deck with a thin blade saw. Peal the fiberglass off trying not to damage it. Dig out the rotten core, clean up the area. Decide on what you are going to use for a new core. Wet out the area with epoxy and then apply thickened epoxy evenly and lay down the new core. Weight it down until the epoxy has gone off. Do the same with the top fiberglass deck. After it has gone off grind a valley along the cuts in the deck and lay a layer or two of 1708 across the cuts. Sand and then apply filler to fair the deck sand again as necessary. Then paint the decks with a nonskid paint. I like Kiwigrip. It is latex so simple cleanup. You can make it very aggressive nonskid or not so aggressive.

BTW, Boatworks Today has some videos on core replacement.

Perhaps we should start at the beginning, always a good place to start - what is your deck? Some are suspecting fiberglass with plywood core, but is it that?

Yes it is fiberglass with plywood. I can’t figure out how to post photos. I have a repair man helping me. He wants to go from the bottom. I think it sounds like the top is better. He can reach the bottom through the storage cabinets from the inside. But if you think the top is a better way. Thank i

Cut the deck with a thin blade saw. Peal the fiberglass off trying not to damage it. Dig out the rotten core, clean up the area. Decide on what you are going to use for a new core. Wet out the area with epoxy and then apply thickened epoxy evenly and lay down the new core. Weight it down until the epoxy has gone off. Do the same with the top fiberglass deck.

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Why on earth would you be bothered trying to save the old fiberglass?
The amount of effort trying to get it off in one piece and then prepping and sanding it to stick to the core is more than its worth.

I have read an article about going in from the bottom. They were able to do the repair but they said they should have gone in from the top after they were done. I guess it was really difficult working against gravity. They were always covered in dripping resin and trying to get all the voids filled was not easy. But each to their own.

Simi 60 said:

Why on earth would you be bothered trying to save the old fiberglass?
The amount of effort trying to get it off in one piece and then prepping and sanding it to stick to the core is more than its worth.

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You are not going to get it off in one piece if the area is large at all. That is why I said to cut it out in sections. We have done several places on a previous boat and it was not that hard to get it off and ready to go back in. Our current boat has had several core replacements and they were able to reuse the top glass.

Comodave said:

You are not going to get it off in one piece if the area is large at all. That is why I said to cut it out in sections. We have done several places on a previous boat and it was not that hard to get it off and ready to go back in. Our current boat has had several core replacements and they were able to reuse the top glass.

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I am a boat builder by trade and am doing my deck now as well and the labour involved in cleaning and sanding an old piece of glass is simply not worth it and I'm not even paying wages.

Far easier and a better job in my eyes to roll out new cloth, mix epoxy and do it right.
12oz double bias is cheap, epoxy resin is cheap, cost of labour to clean and sand an old bit of glass is not.
But, each to his own.

Is there teak on top which you are trying to preserve by going in from underneath? If so, the teak and it`s myriad screws entering the fiberglass sandwich containing the wet rotting teak is part of the problem and needs to go, so attack from the top, and as Simi says,lay fresh fiberglass, two layers to replace the stiffness the teak afforded.

If instead you are dealing with a moulded fiberglass deck, the deck is the top layer of the fiberglass sandwich. There could be aesthetic virtue in neatly removing it to access and renew the core, and relay it. Here in Australia, and I expect elsewhere,I`ve been told you can buy preformed flat hatched fiberglass for deck replacement if you need it.

BruceK said:

Is there teak on top which you are trying to preserve by going in from underneath? If so, the teak and it`s myriad screws entering the fiberglass sandwich containing the wet rotting teak is part of the problem and needs to go, so attack from the top, and as Simi says,lay fresh fiberglass, two layers to replace the stiffness the teak afforded.
.

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Or simply use thicker ply.
Most likely cheaper than the extra glass and epoxy resin and less labour.

Reality is you won't get much extra if any stiffness from an extra player of glass on top.
If it was a layer on the underside of the ply, so effectively a sandwich construction and making an I beam, different story entirely.


https://en.m.wikipedia.org/wiki/Sandwich_theory

Very sorry for your loss, and welcome aboard. Since you mention going in from the inside of cabinets, I assume you’re talking about fixing soft spots, not the entire deck. If that’s the case, the “spots” are going to end up being much (MUCH) larger than you now think they are, so you’re very likely to end up having to move outside the cabinets anyway. It will be a lot less work to do it from the top. There are several good threads on the Hatteras Owners Forum, complete with pictures, showing decks being replaced from below - it isn’t pretty. I like doing small to medium fiberglass jobs, but the decks were too big a job for me. After getting breathtaking quotes from a couple of big yards, I found an independent fiberglass guy at a strip mall repair yard in South Carolina who did a fantastic job for a pretty small amount of money. He ended up having to remove and rebuild the pulpit in addition to recoring half the foredeck and a couple of square feet under each wing door on the side decks.

polly sierk said:

Yes it is fiberglass with plywood. I can’t figure out how to post photos. I have a repair man helping me. He wants to go from the bottom. I think it sounds like the top is better. He can reach the bottom through the storage cabinets from the inside. But if you think the top is a better way. Thank i

Click to expand...

Here's one way to post pics:

1. Reply to the post
2. You may have to hit the "Go Advanced" button
3. Click the paper clip icon
4. In the dialog that pops up
5. Click "Browse", select the pic you want to post. Repeat for more pics
6. Click "Upload"
7. When the pic(s) are uploaded click "Close This Window"
8. Click "Preview Post" to make sure all is as you want it
9. Click "Submit Reply"

Should you not like woodwork there is a plan B,

Remove everything , hardware and teak overlay from the deck.

Use a very nasty grinder with a thick foam pad and silicone carbide 20 or 16 grit to clean everything down to bare glass.

Use epoxy resin and lay on layers of 1-1/2 oz mat 24oz riving and mat again.

When mostly cured lay on your favorite foam core material pre- cut to fit , with more epoxy buttered on the underside.Have sand bags ready to hold down the foam core.

After it cures, glass over the top of the foam with good polly resin , same mat & roving layup till 3 mat & 2 woven robing are installed. An extra layer or 3 over the windlass and anchor handling area is fine.

Now being dry the wood interior will dry out and stop rotting and not need to be replaced.

This technique is not cheap , but should give a forever cure that will take waves coming on board the deck. Same weight as teak overlay

Learning to lay down GRP is about 15 min of instruction for new migrants in FL , the hard part is all the prep and collecting the materials.

How big is the wet spongy area and how many?

Check out Boatworkstoday.com on you tube - some really good videos on fixing soft decks. I'm doing a spot about 3 x 5 ' on my SeaRay right now, really very easy fix.