What should I do to coat the Hull?

[sandrone]

Yesterday I decided to work on my newly purchased 1971 Glassmaster boat (That has not been in the water yet). After thorough inspection, I discovered the plywood floors were waterlogged and rotten so I removed them. Now that the hull is exposed, I want to coat it with something as a precautionary measure before putting the flooring back in. I don't see any holes or cracks in the exterior, but I would hate to do all that work to find out the boat is leaking and have to tear it all back out. So here are my questions:

1. What should I coat the hull with?

2. Should I coat the underside of the subfloor? If so, with what?

3. Once the (2) layers of plywood flooring are reinstalled, what should I use to coat the inside of the boat & top of new flooring?

Thanks

 

[UncleWillie]

Re: What should I do to coat the Hull?

I suspect you may not be done tearing out yet!
If the flooring was rotting, the stringers are likely worse!
They only look good because they are inside of the fiberglass.
But it is just a "Pig in a Poke!"

The bottom (and top) of the flooring can be fiberglass.
The hull is already fiberglass and waterproof.
Coating/Painting is more of a cosmetic than a functional issue.
Don't paint it until you get the new stringers glassed in.

 

[tpenfield]

Re: What should I do to coat the Hull?

Got any pictures that you can post?

There should be some structural members that were/are between the hull & the floor . . .

Any particular reason to do 2 layers of flooring?

 

[sandrone]

Re: What should I do to coat the Hull?

Uncle Willie, If I understand you correct, the stringers (the ridges the floor rested on) are not fiberglass but wood wrapped in fiberglass? There were a couple that looked like a basket weaving coming loose, but only in a few small spots. So the stringers also need to be removed/replaced and then glassed in?

 

[sandrone]

Re: What should I do to coat the Hull?

tpenfield, I didn't think to take pic's yesterday because I have to go back and clean my lines up a little better, but I will post them soon. I'm not sure why there was two layers of flooring. This is my first boat, so I was assuming that was the original floor. I will say that I was afraid to cut the floor back to close to the side walls so there is about a 6" portion around the walls that I was going to leave. I Then would insert the first layer back in the cut out section and overlay the second layer over the entire floor.

 

[tpenfield]

Re: What should I do to coat the Hull?

The task would be to assess the condition of the stringers to see if they needed to be replaced along with the rest of the work that you are doing. It is fairly common that the stringers rot along with everything else. Since they are glassed in, you typically need to drill a few test holes in the sides of the stringers where it looks like there may be problems.

 

[UncleWillie]

Re: What should I do to coat the Hull?

Uncle Willie, If I understand you correct, the stringers (the ridges the floor rested on) are not fiberglass but wood wrapped in fiberglass? There were a couple that looked like a basket weaving coming loose, but only in a few small spots. So the stringers also need to be removed/replaced and then glassed in?

Correct! Wood wrapped in fiberglass.
If they were coming loose anywhere they are likely shot everywhere!
Drill into a spot you think looks the best.
Does nice dry White wood come out in shavings?
Or does the drill bit just punch through to the other side as soon as it clears the glass?
If so, you do not have stringers, you have fiberglass tubes filled with mush. Sorry, but very common.

You have two layers of flooring because someone covered the original rotted floor with a second floor that has now also rotted.
To do this correctly you will need to remove the rub rail, and all the fasteners you will find under it, and then pull the cap (Top Half) of the boat off.

There are many examples in the restoration section showing how all of this is done.
You are not the first person to have this problem; or the last.
This is going to take a few hundred dollars to fix; but a few hundred hours may be needed also.
If you hit some big waves at high speed with rotten stringers; it is possible for the hull to split open and sink the boat.

I a moment someone is going to jump in here and explain that boats do not have floors; they have decks and soles.
We won't deal with the nomenclature until you get this "Floor" replaced.

 

[sandrone]

Re: What should I do to coat the Hull?

Correct! Wood wrapped in fiberglass.
If they were coming loose anywhere they are likely shot everywhere!
Drill into a spot you think looks the best.
Does nice dry White wood come out in shavings?
Or does the drill bit just punch through to the other side as soon as it clears the glass?
If so, you do not have stringers, you have fiberglass tubes filled with mush. Sorry, but very common.

You have two layers of flooring because someone covered the original rotted floor with a second floor that has now also rotted.
To do this correctly you will need to remove the rub rail, and all the fasteners you will find under it, and then pull the cap (Top Half) of the boat off.

There are many examples in the restoration section showing how all of this is done.
You are not the first person to have this problem; or the last.
This is going to take a few hundred dollars to fix; but a few hundred hours may be needed also.
If you hit some big waves at high speed with rotten stringers; it is possible for the hull to split open and sink the boat.

I a moment someone is going to jump in here and explain that boats do not have floors; they have decks and soles.
We won't deal with the nomenclature until you get this "Floor" replaced.

Thank you very much. I did stand on the stringers while taking the "deck" out and they felt strong. I will take the advice given and drill a couple holes in the spots that give me concern to see what I get. If all is well and the stringers are good, do I not need to spray coat the inside of the hull to protect the stringers from future water damage?

 

[Woodonglass]

Re: What should I do to coat the Hull?

sandrone,
Pics really help us to help you. you really want to make sure the stringers are sound and solid. They are the Structural "BackBone" of the Hull of your boat and need to be solid. You also want to make certain the hull has no holes or cracks prior to putting the deck back in place. Have you checked the transom to ensure it is sound? 42yr old boats usually have issues with the Deck, Transom, and stringers. The first link in my signature below has a lot of good info that you might be interested in.

 

[sandrone]

Re: What should I do to coat the Hull?

sandrone,
Pics really help us to help you. you really want to make sure the stringers are sound and solid. They are the Structural "BackBone" of the Hull of your boat and need to be solid. You also want to make certain the hull has no holes or cracks prior to putting the deck back in place. Have you checked the transom to ensure it is sound? 42yr old boats usually have issues with the Deck, Transom, and stringers. The first link in my signature below has a lot of good info that you might be interested in.

I plan on taking pic's this evening, boat is stored at a friends house. Since this is my first boat I am not up on all the terms but I did google definition of transom and I would have to say NO, I didn't check the transom. I'm guessing by the definition, this would be a piece of wood that is connected to the stringers towards the back of my boat. If this is so, I haven't removed the floor that far back yet. Thank you for the advice and I will post the pics as soon as I can snap them.

 

[mwe-maxxowner]

Re: What should I do to coat the Hull?

The rear 'wall' of your boat is the transom. It gets its strength from a core of plywood, with an inner and outer skin of glass. To check it drill a few test holes, from the inside, down low in the middle. It should be over two inches thick in the center, so drill your sample about an inch deep. If the shavings are brownish red, or wet, it should be replaced. If they are light and dry, its good to go. My first test hole on my first boat yielded a good trickle of water...and it seemed fine to me beforehand.

 

[sandrone]

Re: What should I do to coat the Hull?

The rear 'wall' of your boat is the transom. It gets its strength from a core of plywood, with an inner and outer skin of glass. To check it drill a few test holes, from the inside, down low in the middle. It should be over two inches thick in the center, so drill your sample about an inch deep. If the shavings are brownish red, or wet, it should be replaced. If they are light and dry, its good to go. My first test hole on my first boat yielded a good trickle of water...and it seemed fine to me beforehand.

Thank You for the info. I do have a question. If I drill these holes to check the stringers and the transom and things look ok, haven't I just exposed these structural elements? What should I use to protect the wood where the holes were drilled? (I'm thinking positive as you can see)

 

[Woodonglass]

Re: What should I do to coat the Hull?

There's a product call 3M 5200 sealant. It's Permanent and you'll never have to worry about the holes again.

 

[sandrone]

Re: What should I do to coat the Hull?

Many have asked for pic's so I took a few last night. Unfortunately the pics aren't the best since the only form of light I had was the flash. I will take better pic's this weekend when I get back to the boat. The dark spots are areas that are still wet. Hopefully I will do the drill testing on the stringers and transom this weekend. Thanks again everyone for you advice/expertise.

 

[flipbro]

Re: What should I do to coat the Hull?

All that black you see through the glass is rotten wet wood Sorry but you have a job ahead of you

 

[Woodonglass]

Re: What should I do to coat the Hull?

All that black you see through the glass is rotten wet wood Sorry but you have a job ahead of you

This is not necessarily true! It could be mold or other factors. You won't know for sure until you drill into them and check the shavings.

 

[greenbush future]

Re: What should I do to coat the Hull?

My Lone Star from 1960'ish has very similar stringer system at least looking at your 2 pictures. Mine have no wood under the glass by design. They have a 2-3 inch wide metal strip that runs down the top of each stringer, that's what the floor is screwed too. Then they glassed over this the metal strip. I only saw this strip of metal when I had to dig out the old transom and could see the profile of the stringer where it tied into the transom. Made my job replacing the floor and transom a bit easier. Those stringers look just like mine did.
Sure worth a check to see what yours is like, there should be some mulched wood under there if there was wood there right?

 

[sandrone]

Re: What should I do to coat the Hull?

Hello everyone,
I know it has been a while since I have been on here but I wanted to give an update and ask a new question. The stringers were bad/rotted. We have since removed the stingers and installed the new ones and are ready to start the fiberglass. Here is me question for anyone who has done this before.

What is the best type of fiberglass cloth/mat to use around the stringers and the floor?

What weight fiberglass should I use and how many layers at that weight?

Thanks again for all of your help. Will post new pics soon.

 

[Woodonglass]

Re: What should I do to coat the Hull?

Check this out...
"Fabricating Decks, Stringers, and Transoms"