Almost too much info here!! :) Advice needed.

jtpfarm

Cadet
Joined
Jun 1, 2016
Messages
10
So, Im new here. Did some searching and there is almost too much information and different ways of doing things.

For many years I used my great grandpas 1970 14' lund fishing boat. No floor just 3 benches.

I recently purchased a 1980 16' Sea Nymph fishing boat. Its in pretty good shape but the floor has a few soft spots. Not everywhere but one right in front of the drivers seat/ live well, and one right in front of the console. And there appears to be some dry rot. I want to replace the deck and carpet. Im not a hard core boater or fisherman but do enjoy it a few times a year. This boat will spend a lot of time in the shed and will be used on inland lakes in MN. So I have a few questions.

1. I poked around under the deck and where the soft spots are, the foam is a little wet but if I stick my finger down in it, it appears dry. Do I replace it? If so with what? (I would prefer not to but will if needed)

2. What do I use for decking? And do I need to seal it? (boat wont sit out in the rain or by a dock)

3. Do I want to completely seal the top of the deck so water cant get under it? I know drainage is an issue with the poured foam.

4. Is there a way to seal pop rivets for re-attaching the console rather than using boat rivets?

Keep in mind, I have very limited boat knowledge, but I have extensive experience in fabrication, construction, and mechanical repair. I want too keep this simple and low cost but also like to do things right.

Thanks for any help!!
 

Frey0357

Petty Officer 1st Class
Joined
Mar 13, 2014
Messages
313
Hello JT and Welcome to the forum!

Great questions! First of all it is your boat, so by virtue you can do what you wish. We can help you to do as much as you wish to.

1.) Foam is often the wettest near the bottom due to gravity and the porous nature of the foam. When water sits on the top it is really soaked! You can choose to "pop" some loose or take a core sample by taking a piece of PVC pipe cutting an angle and thrusting it/turning it downward to make a hole. Check the bottom of the hole you may find it is dry or you may find water sitting down there. Give it a couple of minutes to "pool". If replacement foam is needed closed cell foam is the replacement! You can choose to replace the current with the same type product or switch to the blue/pink foam panels commonly found at the big box stores, cut to fit!

2.) You can choose to replace the decking with exterior grade plywood or marine grade plywood. The pricing is totally different, marine grade is MUCH more expensive....but it is better. IMHO I suggest exterior grade plywood ACX/BCX or similar and the most important part is sealant! I would not go through all the work without sealing the wood. A member here (WOODONGLASS....WOG) has shared a recipe he has used for several years and coats the plywood well, sealing it. Epoxy is a choice (the best choice), but very expensive. IMHO I suggest using WOG's sealant which uses boiled linseed oil, Spar, and mineral spirits....this is what I used and am VERY happy with the results.

3.) Sealant on the flooring is important, otherwise you will be doing this again.

4.) Sealing pop rivets....there are many ways to fix this challenge. Perhaps pics of the areas you are concerned about would help. In some cases re-bucking the rivets, and in others replacing the rivets are the answer. Sometimes a simple fix is a product like Coat-It or Gluv-It will seal the hull from the inside, and fix leaky rivets.

These are a few suggestions, based on my personal experiences. I am sure there are many more members with suggestions!

Good luck and keep us posted! Send some pics!

Frey
 

Frey0357

Petty Officer 1st Class
Joined
Mar 13, 2014
Messages
313
I forgot to add...in my Sea Nymph I had to take everything out and replace all foam, as it was soaked! I replaced all with sheet foam that I cut to fit. Replacing the flooring now, and carpet is next.....mine is a bigger project, hopefully yours is not, BUT be prepared for more than you may be thinking:eek:....Just my suggestion!

Oh and you NEED to check out your transom closely! Often when flooring is soaked in our tin boats the transom is failing due to water ingress and delaminating unsealed wood. Again I had to replace mine....

Frey
 

jtpfarm

Cadet
Joined
Jun 1, 2016
Messages
10
I forgot to add...in my Sea Nymph I had to take everything out and replace all foam, as it was soaked! I replaced all with sheet foam that I cut to fit. Replacing the flooring now, and carpet is next.....mine is a bigger project, hopefully yours is not, BUT be prepared for more than you may be thinking:eek:....Just my suggestion!

Oh and you NEED to check out your transom closely! Often when flooring is soaked in our tin boats the transom is failing due to water ingress and delaminating unsealed wood. Again I had to replace mine....

Frey

Thanks for the information!

As far as question #3, I meant should I seal the top of the deck by using sealant where the deck meets the hull?

Is the foam designed at all to add stiffness to the hull? If using sheet foam, does it get glued in or just set in?

If I do have to put foam in, I will likely go with the blue sheet foam. Do you know at all how many sheets you used in yours?

I will try to get some pictures posted of it.

As far as the transom, It appears extremely solid. The previous owner drilled new holes to put the motor on as it is not the original. I have poked and beat on it and cant find any signs of rot. It seems the floor is rotting only near the live well. Judging by stains on the live well, I believe it is from overflow of the live well. The spot in front of the console appears to be from a leak in one of the rivets that was fixed with a SS bolt.
 
Last edited:

pckeen

Commander
Joined
Jun 20, 2012
Messages
2,067
1. Decide this after you get the deck off. You'll probably want to replace it. Your best options are rigid foam insulation - comes in sheets in pink or blue - the kind of stuff you use on a house - or pour in foam. Others have used anything from pop bottles to pool noodles. If $$$ is a factor, keep an eye out at construction sites, and offer to carry off their scraps.

2. Any exterior plywood - but not treated plywood - treated plywood rots aluminum. Options are BCX, Arauco Ply, or marine plywood (in order of cost, lowest to highest).

3. Most rebuilders here seal their deck - but seal it on all sides, including edges. I used Spar Varnish for my seats and transom - happy so far.

4. The above advice is good - your other option is to used closed end blind rivets.

Best of luck, and post some pics.....without pics, it didn't happen.
 

Frey0357

Petty Officer 1st Class
Joined
Mar 13, 2014
Messages
313
Thanks for the information!

As far as question #3, I meant should I seal the top of the deck by using sealant where the deck meets the hull?

Is the foam designed at all to add stiffness to the hull? If using sheet foam, does it get glued in or just set in?

If I do have to put foam in, I will likely go with the blue sheet foam. Do you know at all how many sheets you used in yours?

I will try to get some pictures posted of it.

As far as the transom, It appears extremely solid. The previous owner drilled new holes to put the motor on as it is not the original. I have poked and beat on it and cant find any signs of rot. It seems the floor is rotting only near the live well. Judging by stains on the live well, I believe it is from overflow of the live well. The spot in front of the console appears to be from a leak in one of the rivets that was fixed with a SS bolt.

JT,
If you mean sealing the deck off from the below foam and hull, it is my opinion that you should not do that, but should control where the water goes. What I mean by that is ensuring that the deck has a gap between the sides of the hull (not a large gap, but a small one, and channels thru the foam where the water can get to the center of the boat and then travel back to the bilge area where it can be pumped out. If water does get below the deck, and some day it will (IMHO) you also need a way for it to dry out, stagnant wet areas in a boat will always lead to problem areas....the kind you may be experiencing now.

As for the foam, "Yes" the foam does act as a stiffener for the flooring and hull. the foam should be cut to fit in the areas it needs to be in and should meet the hull on the bottom and be trimmed at the top where the new deck will be placed. Does not have to be glued in, a tight fit will keep it in place no problem by the new deck that you place on top. As for how many sheets, it is difficult to tell without seeing your boat and your total plans. For my 16.5' Sea Nymph, I purchased 4 1" 4x8 sheets and so far am very close to using it all. I chose the 1" (well it was on sale to be totally honest :)), because it was easier to cut with a simple razor knife. I found scoring it to about the center of the material will allow you to simply snap it speeding up the process.

Here is some of my foam installation:
IMG_1717_zpsyfl4xsao.jpg
IMG_1694_zpsi5prisbf.jpg


Early on in the process I did glue some of the pieces together, but found that was unnecessary. The sealed wooden flooring goes on top of the foam and metal bracketing. I also have large areas in the stern as can be seen in the 2nd photo on the right that are completely filled with foam (on top of the wooden flooring), and while I am going to place foam in there, I am not planning to completely fill them up, but create more storage with a lid.

I hope this helps!

Frey
 

jtpfarm

Cadet
Joined
Jun 1, 2016
Messages
10
Thanks for the information!! Unless my eyes are tricking me, that looks like 2 inch foam in your pictures?

I am planning on digging into it this weekend. I will post some pictures in this thread or start a new one and give pictures of the whole project.

Thanks again!

Also, has anyone ever used "flexseal" to seal a deck?
 

lckstckn2smknbrls

Lieutenant Junior Grade
Joined
Sep 18, 2008
Messages
1,114
Don't use flexseal or any other spray on sealer in a can. There are proper ways to do things that don't really cost too much.
 

Frey0357

Petty Officer 1st Class
Joined
Mar 13, 2014
Messages
313
Hello again JT. The foam in my project is 1", the photos might look tricky, but that is what it is. It is easier to cut that way as I mentioned before.

As for the Flexseal......it may work for some applications, but IMHO it does not belong on a boat. You are much better off using the sealant approach that I mentioned in either epoxy or WOG formula (mixture of boiled linseed oil, mineral spirits, and spar urethane).

Good luck this weekend and bring back some pics with ya! :)

Frey
 

jtpfarm

Cadet
Joined
Jun 1, 2016
Messages
10
Well, as promised, here it is. Finally got some time and going to start on it. I will post more pictures as it progresses.
 

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