Fiberglass interior?

[SheepdogShaun]

Would you glass the interior of a wooden trimaran?


We finally cleaned, removed most of the plumbing, most electrical, sanded, and are now ready for the next step. I was planning on using Interlux 1026 to seal from bilge all the way up the unpainted walls. Then the plan was to use bilgekote in the bilges and up the outer hull's walls that got the 1026. I was going to use something else a little easier on the pockets but still durable for everything else. Our neighbor suggested laying fiberglass in the bilge areas and up the walls. It seems like a ton more work. If it's worth it, I'd definitely consider doing the accessible parts of the boat. There are place under cabinets though that are unreachable without tearing out shelves. Would you do just higher traffic areas like the center sections of each hull?

[Tusitala]

No, I wouldn't fiberglass those areas. for one thing if there ends up being any voids or airpockets, which is easy to do in hard to reach spots, moisture will collect there. I also would not use the Interlux 1026 in the bilges. I would use one of the marine epoxies for saturating and coating wood. There's many brands, and for the job you're doing any of them would be a better solution. They'll be faster/easier to do, and likely end up costing less. Some of the more common brands that are easily available are West System, System 3, Total Boat from Jamestown Distributors, and RAKA. Spend a little time researching online for your application. Basically if you have everything sanded to bare wood and prepped you would roll/brush 2-3 coats on timing the cure so you don't have to sand between coats. If you use the short roller frames by West System and the yellow foam roller covers that all the brands seem to use you can cut them to fit most areas and use a brush for the really difficult spots and corners. Any place the epoxy will be exposed to UV it will need to be painted. I typically give those areas a quick sand, wipe down and use a 2 part epoxy primer. You can paint or varnish areas that will be exposed and need to look finished. There's plenty of videos on YouTube and on Jamestown Distributors website so you can see what's involved.



Pat

[Singularity]

Originally Posted by Tusitala

No, I wouldn't fiberglass those areas....I would use one of the marine epoxies for saturating and coating wood. ...

+1.

It bears asking, what precise utility did the neighbor perceive would be achieved by adding glass? For high-traffic areas perforated non-slip mats could be used to reduce wear/tear under foot.

[SheepdogShaun]

He suggested fiberglass for adding strength.



I have searched bilge paints for a little while and the stuff I did find was 100 different people with 100 different opinions on what brand and types to use or that you could "get away with using". The guys in my marina seemed pretty happy with bilgekote and it seemed to fair well with people online. I'd rather not spend $100 gal but I'm also a believer that it costs more to do things twice. When I looked at the bilgekote can, it said 1026 to prep for wood. Just went off what the can said. I'm all ears though. I would much rather prime with a pigmented primer rather than a clear.

[Tusitala]

Shaun, is the hull in bad shape, delaminating or in need of reinforcement? I didn't really get that from your original question, I thought it was more about waterproofing. If you're glassing in the bilges or the hull sides you won't really get much strength out of light ( 6-10oz ) woven cloth unless you use a bunch of layers. You'd need something more like 17oz biaxial, either of those approaches will be painful! As for bilge paint, this is okay and doesn't need a sealer or primer:

https://www.defender.com/product.jsp...446&id=3809699

[Chotu]

Looked at your insta to try to see what you're talking about. It looks like this boat is glasses outside and bare wood inside? Or maybe just epoxy coated outside and bare wood inside?

Doesn't look like anything inside behind the decorative panels was treated, right?

If that's correct, DO NOT GLASS IT.

If you glass over raw, breathing wood, you run quite a risk of trapping moisture in the wood. It'll stay better exposed to the air. Keep the wood dry by fixing all the leaks. Rainwater is what kills wood.

You don't need "strength" inside the hull. The hull is the strength. Glassing a plywood hull is typically done outside for the purpose of abrasion resistance. Not for strength. The plywood and joins are plenty strong. Glassing it inside could make it weaker by keeping water in the wood.

Keep your bilges dry/dusty. Be vigilant about that. Then the wood will stay nice and dry and last a long time.

I see some rot. Possibly surface rot.. in one of your pics. There are 2 ports in the pic and the wood is all black. That black is the rot. Keep a good eye on that.

[SheepdogShaun]

Originally Posted by Chotu

Looked at your insta to try to see what you're talking about. It looks like this boat is glasses outside and bare wood inside? Or maybe just epoxy coated outside and bare wood inside?

Doesn't look like anything inside behind the decorative panels was treated, right?

If that's correct, DO NOT GLASS IT.

If you glass over raw, breathing wood, you run quite a risk of trapping moisture in the wood. It'll stay better exposed to the air. Keep the wood dry by fixing all the leaks. Rainwater is what kills wood.

You don't need "strength" inside the hull. The hull is the strength. Glassing a plywood hull is typically done outside for the purpose of abrasion resistance. Not for strength. The plywood and joins are plenty strong. Glassing it inside could make it weaker by keeping water in the wood.

Keep your bilges dry/dusty. Be vigilant about that. Then the wood will stay nice and dry and last a long time.

I see some rot. Possibly surface rot.. in one of your pics. There are 2 ports in the pic and the wood is all black. That black is the rot. Keep a good eye on that.

Correct. It is glassed outside and interior was bare. Well.....everything below the waterline was redone 3 years ago and there was some sort of clear sealer on that wood. The starboard side was redone last year and everything on the inside was left bare. The port side, I removed the paneling and foam insulation. The insulation had held water and there are a few spots like you saw. I was thinking of filler+epoxy for that. If that didn't work, I was going to cut it out and replace. All of the escape hatches leak water so I'll most likely be replacing them with some new gas strut style hatches.

[Redreuben]

You mention above the interior had a clear finish ?
The thing about a clear finish is you can see any discolouration as mould or rot starts in the timber.
If you paint it you find out when your foot goes through it !

[Tupaia]

Just a suggestion - Tung Oil - this would be ideally suited for your project.

The Chinese have used this to treat and water proof their vessels for centuries. Unlike other oils (deks, teak etc) it cures to form a hard shell with no greasy surface.

Look it up. You do need to apply multiple coats 5-7, by brush or rubber (a la French polish) and there should be a delay between the first coats to ensure that they fully penetrate the wood. It can be reapplied to any worn areas without the need to remove old coats. The results can be buffed to a high gloss or less so for a more satin result.

If you choose this option then make sure you only use "pure" Tung Oil there are many products that purport to be Tung Oil but are mixed with other solvents and oils, these do not form a shell and the resulting surface is often greasy.