on my way with stringers

[peacekeeper6]

i bought a bunch of roven, mat and poly. Am now ready to do stringers about to goto lowes for some wood. I am using PT wood. My question is i am doing a 21' tri sonic speed boat. I dont think they make a peice of wood long enough to go all the way the length of the boat, what do i do to "sister" the wood together?

Some pics of the project as i got it. I have since pulled the engine to expose rotted mounts and a load of crap.

 

[tmcalavy]

Re: on my way with stringers

A simple butt joint, ends butted together with binder piece below to cover the seam; or a scarf joint...hold both hands out in front of your chest, thumbs out, turn right hand thumbs down, turn left hand thumbs up, palms together...that's a scarf joint, tapered so when fitted together it equals the original thickness of the pieces of wood.

 

[drewmitch44]

Re: on my way with stringers

I just about there too. Im not going to use the PT ply though. Im going to use regular ply that is double thick. The previous person that did stringers in my boat used PT lumber and the resin that they used did not bond to the stringer wood cause of the moisture im guessing. Im going to use regular Ply cause i dont have a way to dry out the PT ply. As far as the lengths of it im not sure what the correct answer is. The sheets are 4 X 8 and i was going to just make the places where they were cut together different on each stringer. In other words it will kinda work like brickwork. As far as where each stringer will be 2 pieces of ply and piece 1 will be attached to piece 1 at a different place piece 2 is attached to piece 2. Its really hard for me to explain how im planing on doing it. I think that is sistering it. I hope someone with pics chimes in here as im about in the same place you are in. Good luck and you got any pics of what you are doing? I got that shareaproject site but i need to update it really badly as i am a lot farther than it shows! Good luck

 

[peacekeeper6]

Re: on my way with stringers

well, maybe i should go with the PL? it must be cheaper and if its just as good than why not? I dont understand the joints, so am i just to butt them together and glass?

 

[oops!]

Re: on my way with stringers

ok .....lets see......

first pressure treated plywood is the best type of wood to use .....but it must be dry.....or the resin wont stick.....as drew just mentioned....

the jioints are laminated togeather using fiberglass. you also need special screws that will work with pressure treated wood.....

i wouldnt just butt them togeather and glass them....at very least...if you dont want to join them....sister them.....(put another peice of wood on each side of the joint....and glass them togeather) that jind of joint will be structurally weak.

remember ...the pt ply must be dry...totally or it wont suck the resin

hope that helps bud

cheers
oops

 

[peacekeeper6]

Re: on my way with stringers

makes sense, will go with the pt then, and let it sit in the house for a few days. or if it goes straight from lowes to the house and then glass maybe? how do i know if its totally dry? seems dry when i pick it up from lowes

 

[drewmitch44]

Re: on my way with stringers

Its not dry from lowes. I was told it can take months to completely dry to the point where you can use resin on it. There are people who have used heaters and de-humidifiers and covered all that stuff to try and speed up the process but it still takes a long time. Also if you dry the ply too quickly it will warp and be unuseable. This is the reason that im going to go with regular ply. If i do the glass work properly it will never get wet anyhow. I dont have any way to dry out the PT ply. And i dont think you can just let it sit somewhere to dry it out. It has to be dried with dry heat and air circulation and all and i have no way to do that and i need the resin to stick to the wood. The previous owner of my boat used 2X6's PT ones for stringers and the resin did not get into the wood at all and it made for a real mess.

 

[peacekeeper6]

Re: on my way with stringers

hum, things to think on. How far did you get with your bow rider conversion? i am getting pics of my project today and might wanna do it.

 

[oops!]

Re: on my way with stringers

ya drew....how you doin bud?...are ya able to get on the proj?

we miss the updates

 

[drewmitch44]

Re: on my way with stringers

I ended up pulling up all the stringers and doing a bunch of other stuff. I just got done with the transom as i found that was crappy too. So now im about to start with new wood. The transom is done and the stringers are all out completely and i need to update my shareaproject site really bad. Im thinking about laying a layer of mat down to the whole hull whyle there is nothing there before i add the stringers. Id do this just to make sure that there was no problems as far as leaks. I found everything totally crappy when i started the conversion so i had to do the whole 9. I wasnt really trying to do that but you got to do what you got to do. Its taking longer than i thought but i didnt think i would have done the transom and stringers. The transom is done and now its time to add the stringers.

 

[peacekeeper6]

Re: on my way with stringers

what about the conversion? So you really think regular ply will be fine? are you adding mat or anything to your stringers or just coating them in poly?

 

[erikgreen]

Re: on my way with stringers

I'm doing my stringers right now (I hadn't planned to, but I just didn't know when to stop digging out wet wood

I'm using some furniture grade ply I got on sale at Home Depot. It's 19mm stuff, and I'm doubling it up side by side for extra reinforcement. I got lucky with my boat, at some point Sea Ray decided to make stringers rectangular instead of tapered, so no fancy cuts needed.

I know, this ply isn't as good as marine ply, and the glue may not be waterproof... but I figure if the ply gets wet, I'm hosed anyway. I'm fully encapsulating with resin to prevent that. Pics soon.

Anyway, my 2 cents worth is that you should use whatever you like for wood, just make sure it's sealed against water fully, on all sides, and arrange that if it gets wet, it can dry (vents, air spaces, limber holes, etc).

Erik

 

[peacekeeper6]

Re: on my way with stringers

ok, i have another question, by my calculations i need 14 ft of stringers, is this common? do i need to sister the joints?

 

[qaztwo]

Re: on my way with stringers

When I redid mine the stringers would have been to long for a single piece of wood. I decided to place an in floor cooler right between the captain seat and passanger seat. Made 2 bulk heads and cut stringers to go between them. works great would show you pics, but had them on yahoo and forogt to move them before they shut down there pic section.

 

[peacekeeper6]

Re: on my way with stringers

so basically you put two bulkheads in and glassed the ends of the stringers to them?

 

[qaztwo]

Re: on my way with stringers

76 srv200. If only I had a pic. redid engine mounts and stringers. at the end of engine mounts placed a 1st bulk head, ran stringers which on mine was only two to 2nd bulk head. The first space forms the ski locker, on yours would form the gas tank space. cut second set of stringers and placed between 2nd and 3rd bulkhead.that space made a nice 2foot by three foot cooler. finished runing stringers from final bulkhead forward. you could just as easily scarf joint some stringers together just thought I give you another idea. Also since the bulk heads run out to the sides of the boat gives my seats extra support.

To answer your question yes.

 

[peacekeeper6]

Re: on my way with stringers

sounds good i think i will do that then.