PVC board as stringers??

[Dquinn]

Anybody have an experience, knowledge, or advice on using PVC board for a stringer? I'm restoring a 1984 Harris kayot floteboat. Pulled the floors out today to start my resto and the floor had been capped by one of the previous owners years ago. They used some pieces of PVC board to scab their new floor to what was left of the original floor. Everything everywhere was rotted to hell and back except these scabbing pieces, and they were holding friggin strong to one decent piece of wood. Original plan was to just build them out of wood and glass them in very well, but seeing that has me curious about the material. Guess my main concern is how the resin and glass would bond/react with it, maybe how it would hold screws for the floor cap long term, water resistantance. Plan with wood was to drill pilot holes, fill with resin, then put screw in for floor. Would probably do the same with PVC if it is a viable options. TIA!

 

[matt167]

topic comes up all the time as well as trex decking.. The answer is Coosa board is really the only non wood product that can be used. Starboard can be but is iffy due to thermal expansion

 

[Dquinn]

topic comes up all the time as well as trex decking.. The answer is Coosa board is really the only non wood product that can be used. Starboard can be but is iffy due to thermal expansion

Thanks. I figured it had been talked about a lot. The boat is 22ft long and about 7ft wide and has 4 full length stringers and 2 half length stringers so I will just have to see what I can get out of a sheet of coosa and may just go with wood. Depends on price I know coosa is very high but also worth it

 

[Scott Danforth]

Pvc has no strength

Wood lasted 38 years with shoddy 80s workmanship. If you do it right, wood will last long after your pushing daisys

 

[Dquinn]

Pvc has no strength

Wood lasted 38 years with shoddy 80s workmanship. If you do it right, wood will last long after your pushing daisys

Exactly. I've been telling myself that this whole time and I still keep trying to find an even better way to do it. Haha.

 

[chevymaher]

We all go through it. Just do it right and take care of it.

 

[matt167]

A sheet of Coosa 1" thick is going to be over $600 shipped.

When I re do my little Starcrafts transom, I'm considering Coosa, as it's the only structural plywood in my tin boat, but a half sheet isn't that expensive..

 

[Scott Danforth]

Exactly. I've been telling myself that this whole time and I still keep trying to find an even better way to do it. Haha.

Mold built stringer tubs glued together with plexus (and the glue joints eventually fail) is the new method

However some companies still use wood

Boats are still only designed to last 15 years

 

[Lectro88]

Exactly. I've been telling myself that this whole time and I still keep trying to find an even better way to do it. Haha.

I myself have kicked around other unproved materials and methods.
Considering I have hoarded almost enough cull 1x's & 2x's from box stores at .10 - .30 cents on the dollar to build a small viking ship.
And it only requires some cuts or rips and scarf/lap jointing. (that I enjoy doing anyway)just really time consuming.
Why not just go with wood.
And my 69 was wood originally and lasted 52yrs.
My argument for "my" build, Is I rebuilt in same materials as original build.(its like original)kinda sorta, but way better.
So also like Scott said, and I have thunked. I will be making dust a long time before any rebuild is needed, especially doing in epoxy.
Just take your time, is my thought.

 

[Dquinn]

Thank y'all. I know a guy here that used to build boats and still runs a marine store. I've asked him for advice over the last few months and he's confident if I do it right with wood my grandchildren (and I'm 33yrs old) will enjoy the boat as it's stored out of the weather anyway. Seeing everything rotten but that board had me curious but I will definitely be going with wood and glassing it in.

 

[Lectro88]

Thank y'all. I know a guy here that used to build boats and still runs a marine store. I've asked him for advice over the last few months and he's confident if I do it right with wood my grandchildren (and I'm 33yrs old) will enjoy the boat as it's stored out of the weather anyway. Seeing everything rotten but that board had me curious but I will definitely be going with wood and glassing it in.

There are a 100 different ways you could approach this.
Just know anything you do will most likely be better than factory.
Polyester will do, lots of folks use it with no problems.
However it is not as strong of a bond or as water turning as epoxy.
Obviously a little more money but epoxy also has a much longer shelf life.
Many little quirks as to which bonds over the other, a little research will reveal that or ask, we will get you through it... and then again..
You may know all this already.
Wish you the best,
Don't give up after you jump in feet first up to your elbows.
Welcome to the club, I leave that out a lot.

 

[Dquinn]

There are a 100 different ways you could approach this.
Just know anything you do will most likely be better than factory.
Polyester will do, lots of folks use it with no problems.
However it is not as strong of a bond or as water turning as epoxy.
Obviously a little more money but epoxy also has a much longer shelf life.
Many little quirks as to which bonds over the other, a little research will reveal that or ask, we will get you through it... and then again..
You may know all this already.
Wish you the best,
Don't give up after you jump in feet first up to your elbows.
Welcome to the club, I leave that out a lot.

Thanks! A good deal of what I've learned is from boatworkstoday's YouTube page. He's a great teacher and he is ultimately why I decided to go with poly. He does a few comparison videos you may be interested in watching. Showed that chop strand and other mats are help together with styrene and poly has styrene in it and it breaks down that styrene and absorbs really good into the mat. Layup was a noticeable difference. I really wanted to use epoxy until I saw that, the price, and another strength test video he did. I'm definitely elbow deep at the moment! Pic attached

 

[Scott Danforth]

you will need to pull the cap and the drive/engine prior to cutting into the floor

 

[Lectro88]

Thanks! A good deal of what I've learned is from boatworkstoday's YouTube page. He's a great teacher and he is ultimately why I decided to go with poly. He does a few comparison videos you may be interested in watching. Showed that chop strand and other mats are help together with styrene and poly has styrene in it and it breaks down that styrene and absorbs really good into the mat. Layup was a noticeable difference. I really wanted to use epoxy until I saw that, the price, and another strength test video he did. I'm definitely elbow deep at the moment! Pic attached

I have seen his video's
He does very respectable work, and informative too.

 

[Lectro88]

I looked at your pic and chuckled under my breath.. About all the several 100's of projects that I have seen, seem to almost have the same look.. including both of mine.

 

[gsh]

I watched a video about how they make modern fiberglass boats and they don't use any wood at all.
The hull is formed in a mold and so are the stringers and interior/cap. When they hull is ready, they pop the stringers out of the mold, put them in place and glass the stringers into the hull. Then they cut holes to put foam into the stringers and then glass the holes over.

After the stringers are in they do the wiring and plumbing.

Once the wiring and plumbing is done, they put on the interior/cap.

Even the transom is just fiberglass.

This makes me think that the wood was originally there not so much for strength as to give the builders something to screw into. If you do a fiberglass deck you shouldn't need to use screws at all which means you shouldn't need any wood inside the stringers.

 

[Scott Danforth]

I watched a video about how they make modern fiberglass boats and they don't use any wood at all.

stringer tubs as stated in post #8

depending on the factory, they each add foam a bit different some hose the foam on the bottom side of the deck and rough shape with an electric chainsaw to fit into the hull.

 

[Dquinn]

I'm avoiding pulling the cap off at all costs, being it's huge and it's my first big project, but the motor and drive are coming out and I'll be redoing the bulkheads and transom. I do have a backhoe I can rig to pull the cap if necessary. The guy I mentioned that owned the boat store told me about that woodless stringer idea. He used to build boats. Said you can use wood to form your stringers, coat them in floor wax, glass them over, then pop the glass off once it's cured. Then fill with foam after you glass them in. It is a tempting idea. However it goes it'll be right when it's done. I'm very peculiar about the things I do, probably to a fault for most people. And I really love this boat so I'm gonna be picky!

 

[Scott Danforth]

You can use your garage rafters and ratchet straps to pull a cap

 

[Dquinn]

You can use your garage rafters and ratchet straps to pull a cap

I did consider rigging up in the rafters. If it comes to that I might do that. I only have one open bay do hopefully I could get it high enough to secure it and work underneath it.