Stringer / transom question

[Robj]

Hello, I have a few questions regarding my present project which is a 18' bowrider. I am using ISO polyester resin for this project. I have installed the stringers, and have a few questions regarding the next steps:

Between the end of the stringer and the transom, there is a 1/4' gap, should this gap be filled with resin putty? or 5200? or just tab the stringer to the hull?

What is the best way to install bulkheads, should the entire bulkhead be bedded to the hull in resin putty? or a gap left between the bottom of the bulkhead and tabbed to the hull?

What is the best way to secure the fuel tank? It is a plastic tank that sits between the stringers and bulkheads.

What are the benefits of coating the hull and stringers with gelcoat, other than for color? Can I just coat everything with waxed resin? My main priority is for waterproofing not appearance. Is gel coat more water resistant than just plain waxed resin?

Thanx for your help. Have a great day.

Rob.

 

[sdunt]

Re: Stringer / transom question

The transom transfers the force of your motor to the stringers, that transfer it to the rest of the boat. You want your transom SOLIDLY attached to the stringers. I added braces on my boat, check my shareapage. Bulkheads - should probably be attached to hull, stringers, etc. but keep in mind the bilge - drainage situation.
I think Gelcoat is ISO resin that is more water proof than poly resin. So if you are already using ISO I don' think there is any advantage to using the gelcoat. Gelcoat is used on Polyresin construction because it is more waterproof.

 

[OhioLowell]

Re: Stringer / transom question

Rob,

If it were me. Now remeber to keep in mind that I'm a twit! lol

I would fill your little gap with a thickened resin putty(maybe thickened with 1/32 milled fiberglass for strength). I'd build out a small fillet all the way around the stringer then tab it into the transom with fiberglass tape 2" then 4-6".

As for your bulkhead (remember twit here8) ). I would think it should be filleted and tabbed in all the way around. Bulkheads in my mind serve to reinforce the hull structure, stringers, etc. I agree about the drainage issue though. I would just allow a fair sized limber hole in the bulkhead this would allow for adiquate drainage.

As for the fuel tank I've got nothing there. Sorry!


Best
Lowell

 

[Robj]

Re: Stringer / transom question

Thanx guys,

That ain't no twit doing that restore Lowell. Great job, keep it up. Read the updates daily, that string is Boat Rebuilding 101.

My concern is with setting up hardspots. If I fill the gap between the stringer and transom with putty, it creates a hardspot. Should this be a concern, or is using putty and then tabbing it the way to go? My transom is mostly 3/8'' thick glass with two pieces of 2'X2' ply 3/4'' thick laminated togtther, in the middle where the outdrive goes. Where the stringer ends it is 3/8'' glass.

With the bulkheads, again hardspots are a concern. Should they be bedded to the bull and then tabbed, or keep a 1/4'' gap between the hull and bulkhead and then tab it in.

Only want to do this once, the right way.

Thanx for your input and have a great day.

Rob.

 

[Yacht Dr.]

Re: Stringer / transom question

hello rob ... heres what Id do m8, and why.

Stringers: hmm..tough call as to what is perfecto for your boat. some layouts of stringer systems have no affect on hardpointing..but some do ( depends on the Energy transfer from your motor dispursing throughout your hull ) soo.. I normally just bed the stringer gap with Micro fairing compound. wont create a hardpoint but will allow you to do a good wet layup without air gaps

Bulkheads: I never hardpoint them..ever..I use the same micro ballons for that and for the same reason mentioned for stringers..

Inside.. to gel or resin: If its only for waterproofing then I would just use your waxed resin. ( now..Gelcoat is easier to clean and looks better HOWEVER, I Suggest never to gelcoat where you dont need to. IF you did have damage to your boat you can cleanly inspect the inside for through damage without having to grind off all that Gel .... IMPO ).

Plastic Fuel Tank : welp..this is what I like to do ( some may dissagree ) 1. determine where you want to "strap" it down. 2. put wax paper on your strap points. 3. layup some straps with glass. 4. Remove and clean glass straps ( making sure to prep bottom of straps. 5. rewaxpaper areas. 6.run a good thick 5200 gasket on your glass strap where it meets the tank and put it back into place. 7. let it cure then remove the straps again so you can clean and pretty up your edges were 5200 spoogeed out. 8. re-install your straps and glass them in on the ends.

Now this way you dont have a hard bond to the tank..but if you need to remove the tank you just cut your tabbing out.

Hope this helps .. Cheers m8

YD.

 

[Robj]

Re: Stringer / transom question

Thanx YD,

The stringers I bedded in a mix of resin, chopped strand and cabosil. It was a big debate, and after much thought I decided to do it that way. The old stringers were done in the same manner, so I think they will be
OK, I hope. With regards to the gap between the transom and the end of the stringer what should I fill that with or nothing.

For the bulkhead, leave a 1/4 inch gap and then bed the bulkheads with a mixture of microballons and resin?

Thanx for your help and have a great day,

Rob.

 

[Yacht Dr.]

Re: Stringer / transom question

your tiger hair will do on your stringer to transom.

bulkeads..aye..balloons/resin mix.

You do plan on tabbing strongly..

YD.

 

[Robj]

Re: Stringer / transom question

Thanx YD,

Peanut butter mix for transom to stringer and microballons for bulkheads to hull. And of course tabbing them in afterwards.

Thanx again,

Rob.

 

[andy6374]

Re: Stringer / transom question

As for the bulkhead, yes bed it in thickened resin and then make fillets and then tab it into the hull with increasing widths of glass. This reduces the hardspot by spreading any point loads.

As far as the transom is concerned, you've got 1.5" of plywood in there, there will be no hardspot, as the transom isn't going to really flex anyways. But fill the gap with the resin reinforced with milled fibers then tab with glass in the same way I described for the bulkhead.

 

[OhioLowell]

Re: Stringer / transom question

you've got 1.5" of plywood in there, there will be no hardspot, as the transom isn't going to really flex anyways. But fill the gap with the resin reinforced with milled fibers then tab with glass in the same way I described for the bulkhead.

I was kind of thinking the same thing. If the transom was just the 3/8 glass then I'd be weery of tabbing into it,but with all that wood I would think it would be pretty hard to have one of those stringers wear out a spot on the transom. Just my thoughts. (again twit!)


Lowell

 

[Robj]

Re: Stringer / transom question

The gap that I was refering to was between the 3/8 inch glass of the transom and the end of the stringer. That part of the transom does not have any ply. The glass part of the transom would be tabbed directly to the end of the stringer.

Thanx for your input.

Have a great day,

Rob.

 

[Robj]

Re: Stringer / transom question

I was just working on the boat, getting ready to install the bulkhead and noticed that one stringers was out by 1/4 inch from the vertical. Unfortunately I installed it at an angle. The stringer is 4 1/2 inches tall. Is this worth removing it and reinstalling?

Thanx.

Rob.