need some help on new foam, stringers, and deck

[kennyboater]

last weekend i purchased a 1973 14ft arrow glass with an 1984-85 25hp merc. spent a few days on the motor, just got it running. now, time to turn my attention to the rotten foam, stringers and deck....

i started tearing the deck out, stringers, foam, and whole deck are completely rotten.

1. what foam do i use to replace my water logged rotten foam? (there is not much)

2. when i put new stringers and deck in, i have have to fiberglass them in?
-can i just use some construction grade adhesive to hold stringers in?
-what type of wood do i use for stringers?

3. per q 2, if i do need to fiberglass stringers in, do i use cloth or mat? what type of resin?

4. after stringers are in, either using adhesive or fiberglass, what type of plywood should i use for deck...pressure treated, marine...?

5. for plywood deck, do i have to fiberglass it in? if so, mat then cloth? I do not want to be covering with carpet, so how do i get that finished look?

6. someone told me that instead of fiberglassing the plywood deck, i can use something called lizard skin and paint it on? ever hear of it?

i have been reading on this site, and i see that rotten deck and stringers are a common problem.

thanks in advance

 

[kennyboater]

Re: need some help on new foam, stringers, and deck

need some help guys. ive done lots of reading here in this forum still need some help on the questions above.

thanks so much

 

[Ride The Lightning]

Re: need some help on new foam, stringers, and deck

Hi Kenny,

I will try to help you:

1. You do not use any foam unless you want to have the same problems in two years again. There exists no foam which do not assimilates water!

2.+3. You have to fiberglass them in. I would use 350er fiber glass matting (350 gr. per m?) and Polyester resin. Expoy resin you usually use for underwater areas (Epoxy does not assimilate water at all), inside the boat you can use polyester resin (be careful when working with that stuff, always wear goggles and a breathing mask!).
You can use the polyester resin to connect the stringers with the hull. Use water proof (you call it marine?) ply wood. The stringers should have a thickness of 14-16mm, I suppose.

4. The same wood as for the stringers but thickness of 12-14mm.

5. You glue the deck on the stringers with polyester resin again. Besides that you can bolt them together with high-grade steel-screws. You get the finished look by laminating three plies of 350er fiber glass matting on the deck to the sides of the hull (sand the hull before that a little bit).

6. Sorry, never heard of that.

And the last thing: do not forget to paint the woods with protective paint against fouling (the bottom side, do not paint the parts which shall be laminated).

Hope that helps. If you have any questions I will try to help you.

Regards from Hamburg,
Lars

 

[kennyboater]

Re: need some help on new foam, stringers, and deck

Thanks Lars! that helps a ton!

so take out old foam and do not put any back in?

"And the last thing: do not forget to paint the woods with protective paint against fouling (the bottom side, do not paint the parts which shall be laminated)."
----what type of paint?



after reading more on here about deck/stringer replacement, i started thinking about the transom...

just checked it out; its rotten too...
ill try to take some pics of it and post. i suppose its not as easy as just trying to take out rotten wood (in transom) and dropping new wood in there (fiberglassed)?

ill do a seach on transom repair, but can you point me to a good post or two about it?

again, i really appreciate the help!

 

[Ride The Lightning]

Re: need some help on new foam, stringers, and deck

Right, you should not put any foam in. Try to install access hatches in the deck to get potential water out. If it was in the foam, you would have to remove the foam again, thats much more difficult.

I do not know the right translation for the paint: something like wood paint or lacquer perhaps. It helps the wood not to rot because of the humidity you always have in boats.

You are right, if your deck and the stringers are rotten the transom is mostly not at a good state either.

I wrote something for a transom restoration here:
http://forums.iboats.com/showthread.php?t=228608

Show some photos, that would help to see what the best way to restorate is.

It is not that difficult to restorate the transom: just begin

Regards
Lars

 

[slia67]

Re: need some help on new foam, stringers, and deck

Kenny,

I would recommend getting the book "Runabout Renovation", lots of good info.

If you don't want to do that. Do what Lars has said.

When you

"And the last thing: do not forget to paint the woods with protective paint against fouling (the bottom side, do not paint the parts which shall be laminated)."
----what type of paint?

the best thing to use IMHO is the resin you are using to do the fibreglassing.


Doug

 

[jasono2l]

Re: need some help on new foam, stringers, and deck

I know lars said no faom, but you really should consider it. If your boat starts to sink and gets swamped the foam would buy you some very valuable time. Think about it, if manufactures put the stuff in there at an added cost to them, don't you think that is kind of important? Might want to ask the coast guard if it is required on boats with a deck. Just an extra 2 cents.
Jason

 

[Coors]

Re: need some help on new foam, stringers, and deck

Foam is required, under 20'

 

[oops!]

Re: need some help on new foam, stringers, and deck

welcome to i boats.....

just to expand on coors comment.......it is required......means it is the law.....

larrs, lives in germany....and while a respected member of this forum...is not too framilliar with our laws......however his point is correct......

but if you do it right...it will last longer....

also as far as flotation...there is lots of types...from pool noodles to pingpong balls.....to life jackets stuffed under the floor...to proper foam.

2 and yes you need to glass the strings using bolth matt and cloth...(cloth ..in this case is a generic term, that may include many different types and weights).......this will also insure a waterproof covering of the wood you use.


as far as wood......you choose...pt or exterior....exterior will do just as good as marine.

as far as not glassing the deck......there is lots of ways to build a boat.....HOWEVER......the deck is structural...and i would glass it....for many many reasons......

this is some iboats allmost required reading as well

http://70silverline.250free.com/Skankybeast.html

cheers
oops

 

[jcsercsa]

Re: need some help on new foam, stringers, and deck

I know lars said no faom, but you really should consider it. If your boat starts to sink and gets swamped the foam would buy you some very valuable time. Think about it, if manufactures put the stuff in there at an added cost to them, don't you think that is kind of important? Might want to ask the coast guard if it is required on boats with a deck. Just an extra 2 cents.
Jason

I agree with Jason , I would put the foam back in , I am on mine , us composits is the cheaps place i have found, they have it all , where you at ? there in florida , theres also a place in californa the sells on ebay , if your on that side of the nation !!!
If you seal it right , the foam will last 20 + years , its really up to you , I would do some reading an make your own decission some guys say that it just soaks up water and rotts the stringers, and me i say it does soak up some water , its says it 98 precent water proof , and what it adds to the structure of the boat , I think its well worth it !!! on mine its adding 950 lbs of dead lift , so its really up to you , there a guys that is going to use ping poog balls ......{ arent you OOOPS } lol
Its up to you do some reading then decide !!!! john

 

[oops!]

Re: need some help on new foam, stringers, and deck

john....... still gotta figger out how we can have a beer !


and i also own a copy of runabout reanvation...it is the most read book in my bathroom!

 

[kennyboater]

Re: need some help on new foam, stringers, and deck

wow, guys, i really appreciate ALL of your help!!

all of you and this forum is awesome!

i will keep reading and researching...

feel free to throw any more advice, or threads at me that i should be reading.

ill post pics soon.

again,

thankyou

 

[jcsercsa]

Re: need some help on new foam, stringers, and deck

john....... still gotta figger out how we can have a beer !


and i also own a copy of runabout reanvation...it is the most read book in my bathroom!

I agree Ooops , maybe more then one !!!!!!!!!! lol
is that really a good book ????

and kennyboater check out this web site for us composites , theres a lot of info telling about all the products !http://www.uscomposites.com/products.html
there also other one just google and you will come up with 10000 , and ooops has a great one going , as well as mine , { he knows a heck of a lot more the me just dont tell him i said so } hahaha John

 

[kennyboater]

Re: need some help on new foam, stringers, and deck

Lars and Oops, or anyone else willing to help, can you expand on what you said above

"You get the finished look by laminating three plies of 350er fiber glass matting on the deck to the sides of the hull (sand the hull before that a little bit)."

does that mean 3 layers of fiberglass mat and resin on top of the plywood deck? also, do i only use the fiberglass mat, and no cloth?

Oops!, you said, "2 and yes you need to glass the strings using bolth matt and cloth...(cloth ..in this case is a generic term, that may include many different types and weights).......this will also insure a waterproof covering of the wood you use."

how do i know when to use mat, and when to use cloth? im guessing mat against bare wood? if so, then do i need to use cloth once the mat is done over the wood?

sorry for all the questions, just a little confused on when to use mat vs cloth or both...

thanks

 

[erikgreen]

Re: need some help on new foam, stringers, and deck

Foam is required, under 20'

Well, foam is required to be installed by the original manufacturer on boats under 20 feet long. I don't know for certain that it's even required to be installed to resell the boat later if removed.

But the USCG won't check for floatation meeting specs unless you're having a stability test done or something.

It's a personal choice... there are even ways to insure proper drainage if you put foam back in, although eventually it'll still get wet. It's a boat.

I Am Not A Lawyer (IANAL) by the way.

Erik

 

[ezmobee]

Re: need some help on new foam, stringers, and deck

Some people on here have successfully used the pink or blue house insulation foam boards from Lowes/HD cut and pieced to fit. I think if I were doing mine over again that's what I'd use. Might cut and fit some up under the gunnels as well. I think this foam is as darn near impervious to water as you can get. A forum member reported digging some up once near a house foundation that was underground and still dry as a bone. Just my 2 cents.

 

[Ride The Lightning]

Re: need some help on new foam, stringers, and deck

When you the best thing to use IMHO is the resin you are using to do the fibreglassing.

Doug

That's right and the easiest way. But try to make the resin as thin as possible so that it can go deep into the wood. Use Sandpaper before to open woods pores.

I know lars said no faom, but you really should consider it. If your boat starts to sink and gets swamped the foam would buy you some very valuable time. Think about it, if manufactures put the stuff in there at an added cost to them, don't you think that is kind of important? Might want to ask the coast guard if it is required on boats with a deck. Just an extra 2 cents.
Jason

Jason, you are absolutely right. Maybe I am not at ultimate state of affairs so maybe there exists a kind of foam that is exactly made for this application.

larrs, lives in germany....and while a respected member of this forum...is not too framilliar with our laws......however his point is correct......

cheers
oops

Hey Oops, I haven't thought of this. Might be a problem, in Germany a law considering this does not exist, as far as I am informed.

Lars and Oops, or anyone else willing to help, can you expand on what you said above

"You get the finished look by laminating three plies of 350er fiber glass matting on the deck to the sides of the hull (sand the hull before that a little bit)."

does that mean 3 layers of fiberglass mat and resin on top of the plywood deck? also, do i only use the fiberglass mat, and no cloth?

...

The last but one question: right, on top of the plywood.
In my opinion you do not have to use cloth. You start at one corner with one piece of mats. The following mats should overlap with the other ones, so that you have at last nearly at all places on the deck 3 layers. You have to work with the wet-in-wet method, that means, the resin of the subjacent mat mustn't be cured. If that is the case you will have to use sandpaper again because of the wax which had come out. Otherwise the new layer does not last in the perfect way like it should be.

Everything clear? Otherwise ask, I don't mind if you do!
It is important that you know how to deal with the different steps of work because it is much easier then.

I will try to help you with a painting. At the bottom you see how to work in corners: you have to make the angle round, because otherwise you will have bubbles in the laminate. Use therefore resin filled up with ballons or cotton fibers to have a putty.

 

[erikgreen]

Re: need some help on new foam, stringers, and deck

Why use three layers of mat like that? Any reason in particular?

I've used and will use 1-2 layers of fiberglass cloth on the deck... it's mostly for abrasion resistance.

I think one layer of mat would do the same, and the other layers just add weight?

Erik

 

[oops!]

Re: need some help on new foam, stringers, and deck

im on a road trip so i gotta make this short.....ill answer in full later tonight....

(this answer is based on using poly resin)

grind down the hull where the new glass will go in........(rough it up)

clean with acitone....twice

wet stringer with slo cure resin...let it seep into the wood.....wait...

add first layer of MATT.......saturate the matt with resin...no more no less...

add second layer of cloth.....(again...cloth is a generic term).....saturate as above....

add third layer of matt....saturate as above....

thickness of matt cloth will determine amount of sandwich layers.

there is a thousand ways to do it....they will all work...this is the way i was told....by long time boat builders/repairers....

be back on soon....10 ish my time

cheers
oops

 

[Ride The Lightning]

Re: need some help on new foam, stringers, and deck

Hi Erik,

the problem is, that you need structural reserves. If somebody stands on the deck - no problem with 2 layers or 1. But you are in a boat. Lets say someone (100kg) jumps off a quay wall (1m) into the boat. Now you have a heavy load affecting on the deck.
Other example: what kind of boat seats will be installed? Back-To-Back - no problem because you have a big base. But if he installs Single-Seats, you have a small base. Now everybody knows what waves can do while driving fast into them - it gives a huge bash and the complete boat is loaded enormous.
The problem is to be prepared to these situations. And in my opinion it is better to build a strong structure that might be a bit overdesigned as the other way around.
But lets have some other opinions. Photos of the boat might help deciding that.
Aside from that it depends on the thickness of the ply wood deck. If you take 14mm two layers may be enough.

Regards,
Lars