plywood floor

I said that backwards. The stringer needs no lateral bracing on the tension face. Lateral bracing of the compressive face increases the beam strength against buckling failure. A beam or column will never "buckle" under a tension load.

Either way, its braced on the bottom by the hull and at the top by the floor. The fiberglass on the stringer at the top makes it stronger in the weak direction, but doesn't brace it. I consider it braced only if the bracing object is much stronger/stiffer than the object being braced.

Im not sure it matters either way, Im sure something else would break before the stringers fail that way. IMO the stringer system is stronger when a plywood floor is used in lieu of a foam floor. However, I think that foam makes the hull sturdier and stronger.

Im a structural engineer, therefore I see everyhting in free body diagrams and moment and shear diagrams. I can't help it.

Pete, you're too much. Alan posted the dovetails a while back...and I sure haven't posted any scarf joints!

I would learn to make that joint someday if I had a really good reason...but...I picture a sizable guillotine type cutter for this!

BuffaloBFN wrote: 8122pbrainard wrote: JD, If you really want to get fancy, you could scarf them! Geeze Pete?!!?   LOL

Greg,
Remember all the talk about you putting down a clear floor to show off all your woodworking skills? Knowing you, if you did a ply floor, It sure wouldn't surprise me if you scarfed it!!!

I ran my ply perpidicular also. I was able to get the whole floor done with two pieces. I did the first seam with just epoxy thickened with fairing filler. The second I left alone so in case I ever had to get at my exhaust it would not be the end of the world.

As far as cross pieces, what do you mean?

Did you guys have any seams in the floor?   

Im going to use plywood, but Im going to span the plywood perpindicular to the length of the boat instead of parallel. Im doing this for strength reasons, Im not going to put any cross pieces in so I want the plywood to span between the stringers rather than from front to back.

What did you guys do to seal the seams in the plywood or what should I do? Glue them together w/ epoxy sounds like the best option

ryanowen wrote: Fl Inboards wrote: Here is what I use when I re-floor inboards, http://www.coosacomposites.com/ Check out the web site see for your self. This stuff is a little more expensive than good marine ply. Jody, Thanks for the link. Very cool material. Is it any harder to work with aside from having to through-bolt? I'll have to see if it's available here. I'm curious about the price. Ryan

Ryan,
JoeiNY did his stringers and floor in coosa. There's quite a long and very detailed thread on it. It's nice stuff but is is on the expensive side. Joe tells all about it.

WakeSlayer wrote: I did not glass my floor down. I epoxied several blocks down the sides level at the bottom of the floor. The floor just sits on them however and is not fastened to the little support blocks, just the stringers.

Do you have any pics of this? That's kind of what I was thinking about.

WakeSlayer wrote: It is actually a pretty fun job except for the grinding BS.

We'll see about that!

He is a cartoon guy on TV, he was taking his wife out on a date, he was excited and to look good he said....Peg, get out the lazer level I need to shave my sideburns
watch the show sometime

eric lavine wrote: you forgot the good ole hammer and nail Pete

Sorry Eric!!

Silicon Bronze - Threaded Annular Ring Nails

Also known as Bronze Boat Nails or Silicon Bronze Ring Shank Nails.

WakeSlayer wrote: Pete, Funny you say that about the screws. Some came out with the phillips and some I ended up just drilling out after the head failed. I am guessing you are right about the material as the coloring you described is exactly right. I will look to see if there is an errant one left under the workbench of something. I would like to know.

Mike,
Here's a picture showing the head differences between the Frearson and Phillips. I think the picture on the Frearson is slightly off and the slots shown are a little narrow. The key difference is no radius on the inside of the cross intersection and the angle of the tip is different.



The Frearson (also called Reed and Prince) was designed as a anti cam out solution to the Phillips. Going back into the history of wood boats, the plain slotted screw was first used but needed to be driven with great care. If not, and you slipped while fastening down a piece of deck hardware lots of damage was done to a nice varnished mahogany deck. Next came the Phillips answer but to make it easier to make in the cold heading process, the inside corners were radiused and each "wing" of the tip was beveled (relief). The cam out problem still existed especially with a worn screw driver bit. The Frearson was developed without angles and radius giving it max grip. They caught on in the boat industry and were exclusively used by many until the early 70's.

Using a Phillips driver on chromed Frearson deck hardware fasteners is quite damaging! Every once in awhile, I'll see the "newbee" mistake at shows on wood and some early glass.

BTW, Jamestown distributors Frearson bits has them.

Ryan:

With WakeSlayer on this one. I'm busy doing a resto myself. Not to repeat Wake's layup of the floor....but rather to add another member who's gone with this floor set up.

I epoxied my screw holes also.
I did not glass my floor down. I epoxied several blocks down the sides level at the bottom of the floor. The floor just sits on them however and is not fastened to the little support blocks, just the stringers.
My floor is not removeable at all, but in the event of an exhaust failure I could slit the carpet and get the side boards from there back up without too much trouble. The plan is to never have to do so. I installed my side carpet before I put the floor down. I feel it gives it a cleaner look as you have a pretty tight to work with there.
One other thing that has not been mentioned is that you defnitely want to have some drain holes in your stringers to let any accumulated water out.
A lot of factors went into how I did what I did. Take everything you learn from everyone here and decide which pieces of the puzzle suit you best and get after it. It is actually a pretty fun job except for the grinding BS.

I am not a design engineer, but I have stayed at Holiday Inn Express lately. I would think you will lose some rigidity if you just screwed the ply floor down. Plus the screw holes in the stringers would be a water intrusion point. How do you attach it to the hull sides? Would you glass wood strips to screw into?

8122pbrainard wrote: If you follow the CPES, epoxy and care when you glass up the wood, water moisture won't get into the wood. Keeping it out is the key. Once it gets in, it doesn't like to dry out even after extended storage. The wood is like a sponge wrapped up in a plastic bag.

I guess I'm worried about my ability to keep it out though. If I permanently glass in a floor and water gets beneath it through seat bases or hairline cracks or some other means, I can never get it back out again. Trapped water seems to a common theme with these rotten floors. If I could open up the floor periodically, things could dry out a bit. Plus if pool noodles didn't work out, you could switch things up!

Just thinking out loud. What would the downside to a removable floor be?

Thanks for the responses guys. I'm in the info gathering stage right now, and from where I'm starting from, that might take a while.

Hopefully this isn't too stupid of a question... but why not make a floor that's completely removable? Wouldn't that give things a chance to dry out each season?