Need to replace stringers and floor

[jeffengle]

I have to replace the floor and stringers in my sleekcraft. I have removed the floor in the cuddy cabin area basicly with a broom and dust pan. The stringers that run to the transom also need to be replaced. What species of wood is recomended for these stringers. These stringers are also part of the motor mount area. Also, where do I get Cabasol?

Jeff

 

[jeffengle]

Re: Need to replace stringers and floor

I will take a few pics and attach them soon

 

[Robj]

Re: Need to replace stringers and floor

I am using pressure treated ply, use 3/4 inch laminate them together. You must make sure that it is DRY before you start. It took a month indoors for mine to dry out. You will hear people saying not to use pt ply because resin does not stick to it, based on my research and experience this is not true. It sticks just as well as it does to non pt ply, as long as the wood is DRY. You can buy cabosil from your fibreglass supplier. Any shop that sells resin would also have cabosil.

 

[Robj]

Re: Need to replace stringers and floor

Forgot to mention the wood species. I would only use douglas fir pt ply. Douglas fir is the best in my opinion.

 

[jeffengle]

Re: Need to replace stringers and floor

As far as the floor, I am using 3/4 ACX Ply and I have treated it with Thompsons on the bottom to insure no moisture gets in. The stringers need to be really strong because of the 450+ horsepower that I will be running. I was told by a reliable source to run spruce but I also wanted more opinions.

Jeff​

 

[Robj]

Re: Need to replace stringers and floor

Spruce is lighter, but douglas fir is stronger. What thickness is in there now? I would still use ply, and how thick to make the new stringer depends on how thick the original one was. My boat had 3/4'' stringers, the new ones are 1.25''. In your case, I would make the new stringer thicker than the old one, in my opinion by at least 50%, to help spread the load.

 

[jeffengle]

Re: Need to replace stringers and floor

The old stringers are 2 x 6 type of wood that runs only from the transom to the start of the cabin area. The stringers in the cabin area were a solit type of wood also, probably 2x​

 

[klos]

Re: Need to replace stringers and floor

Use 3/4 Douglas fir exterior grade plywood laminated together with resin and mat.

Ply is much stronger than dimensional lumber.

For the sole (Floor) 3/4 is overkill and will just make the boat heavy. 1/2" is plenty for most boats.

IMO I have not seen good results from using pressure treated ply but some might. Exterior grade and marine grade have been proven quality core material for decades. I also restore high HP performance boats so strength is a must.

Also look into www.coosacomposites.com There product is awesome!
similar properties to plywood but 45-65% lighter and NO ROT!
Talk to Jennifer in sales she will send you some samples.

 

[jeffengle]

Re: Need to replace stringers and floor

I spoke with the Sleek / Magic mfg in Lake Havasu City Az today and they told me that whatever I decide to put in make sure that all surfaces and edges have been sealed with a mixture of resin, acetone, and catylst to prevent any moisture to get in, and then cover with fiberglass. They also told me that they use OSB board for their stringers. Of course in the Magic boats the stringers are only about 4ft long because of being tunnel boats.​

 

[Robj]

Re: Need to replace stringers and floor

NO, NO NO, Do not use OSB board. That stuff is junk and I am very surprised that someone would let that stuff get near a boat, and to use it for a stringer, it really makes no sense to me. Go and buy a small piece, and let it get wet. It will swell and start to fall apart. Maybe they pack all the voids between the wafers with resin, sealing it up. It would drink quite a bit as there are many voids between the wafers. I would still use pt fir ply or dimension fir. Fir grows on the coast, in a wet environment thus it resists rot better than some of the other species like pine.

 

[klos]

Re: Need to replace stringers and floor

Definitly no on the OSB, it has no strength. Like IR said when it gets wet it falls apart, Heck it crumbles even when its dry, It's basicaly wood chips, bark, saw dust swept off the floor and glued together.

I think someone at the mfg may have told you wrong but you never know. Besides the goal is to rebuild your boat better than the factory built it.

Seriously think about using a composite core material. get some weight out of the boat and it will realy move.

 

[jeffengle]

Re: Need to replace stringers and floor

On the west coast OSB is used for sheathing and shear panel in the housing industry, They also use what they call para-lams which is made the same way as OSB which they are saying is stronger than glulam beams. Possibly what the mfg was telling me is a form of how the paralam is made. I will be going to the mfg this weekend to find out for sure. On the other hand I will be using straight grain #1 douglas fir for my stringers, saturated in the resin/acetone/catylyst mixture then fiberglassed. Also, the flooring in the cabin area was 3/4 ply originally so that is why I am replacing it with 3/4. I have been trying to attach photos but have not been successful at doing so. Does anybody know what I can do to make this happen. Thank You​

 

[sdunt]

Re: Need to replace stringers and floor

As for posting pictures, just start a share a project - www.shareaproject.com Its free, you can blog along about the project and if you put the link in your signature then everyone knows where to look for info on your project.

 

[Zetman]

Re: Need to replace stringers and floor

.

Also look into www.coosacomposites.com There product is awesome!
similar properties to plywood but 45-65% lighter and NO ROT!
Talk to Jennifer in sales she will send you some samples.[/QUOTE]


Klos, Have you used this stuff before?

 

[Solittle]

Re: Need to replace stringers and floor

The transom in my 23' CC was redone about 5 years ago with the Coosa product. I will never, ever have to even thing about rot in the transom again.

 

[Zetman]

Re: Need to replace stringers and floor

The transom in my 23' CC was redone about 5 years ago with the Coosa product. I will never, ever have to even thing about rot in the transom again.

What about using for a floor repair? Can you paint or use an anti-slip product on it?

 

[Robj]

Re: Need to replace stringers and floor

Jeffengle,

OSB and parallam are two different products. OSB is commonly referred to as waferboard, it is made from Aspen wafers which are glued together under pressure. As a sheeting material I guess it is OK, but I would never use it for a floor or anywhere in a boat. Water is its biggest enemy. Parallam is a product that is made from plywood vineers that are unsuitable for plywood manufacture. Long toothpicks are glued together under high pressure. The product is good, and strong, but it also has many voids. I do not think it would be suitable for boat stringers. If I was to use an engineered wood product, I would use LVL - laminated vineer lumber. It is basically the same idea as plywood, except the grains are oriented in the same direction. This would work, and you can get varying lengths, so you stringer can be one solid piece. If I had access to LVL, I probably would have used it, especially if it was pressure treated.

When you get down to it, fir, dimension lumber or pt plywood are your best bet. I would be real interested in how these manufacturers use OSB or parallam in their boats.

Have a great day,

Rob.

 

[mtnrat]

Re: Need to replace stringers and floor

I emailed coosa yesterday evening and they replied this morning. Gave me the name of the nearest supplier to me. I want to use it for my stringers and floor.

 

[Zetman]

Re: Need to replace stringers and floor

Here is an interesting idea. Since water of any kind is the enemy, I thought of using that Coosa Composite for the floor, or something similar, coating all the stringers with any kind of water proofing, spray liner,epoxy resin, and leaving drain holes to the bilge. So at the end of the day you could wash out your boat with a hose, tilt up and drain the water. Leaving no worries of trapped water and any start to dry rot. Kind of like the aluminum fishing boat I used to have. I think also you could still have floation under the floor but leave a drainge path to the rear. My fear is spending all this money and time on a new floor system just to take a log into the bow only to rip up everthing to fix! I'm just using the K.I.S.S. system thats all. Anybodies input on this idea would be welcome.
Zet

 

[jeffengle]

Re: Need to replace stringers and floor

At this point I am looking at a very low budget. The composite flooring sounds like a really good thing but I can not afford it at this point. I lost my business at the end of February and funds are not readily available. I already have the plywood and buying DF dimensional lumber is not that expensive. Also, the bildge area in this boat is only about 14" - 16" wide, and about 7" deep at the rear. It terminates at the bow in the bed area with a small hatch which you could use as an ice chest. That area has been gel coated so to keep it clean. I also plan to gel coat the entire length of the bildge to keep dirt an such from hanging up and to keep any mildew or mold from starting.​