Floor discovery

[jsakat1]

I started tearing out the floor on my 87 170 striper. I cut about 1 1/2 inches and peeled the fiberglasss off. Rather than find a plywood deck.i found plywood squares and some balsa core the wooden pieces looked like a parquet floor. It wasnt a marine plywood deck all around. Why is that. What was the purpose of that is that common on aquasports? Curious to know.

[RickK]

Yup, all their floors are like that - little squares of balsa wood.  Not sure what the thinking is - maybe having these all oriented a different way the expanding and contracting is less noticeable and that it could dry out easier?

[flounderpounder225]

I explained this to my neighbor who was in the boat building business for 20+ years during the era we are discussing, he said this was very common for a lot of manufactures, the reason is, with one solid sheet of plywood, it is harder to get 100% adhesion all across the surface with no air pockets forming, than using the tile size pieces as has been described on here a few times.  Just think of laying tiles?  Where would all the resin go when putting down the wooden tiles?? Up in between the tiles, theoretically sealing each tile, plus if there was water infiltration, it might stay localized rather than migrating.  Then came vacuum bagging and more advanced materials... and hence the modern deck of today.  But what you and many others have seen is not the scrap pieces of wood laying around, being used to save money as someone a while back theorized, it is just the way they were built?  
Marc

[seabob4]

Marc is pretty right on, as far as this type of coring technique is concerned.  The "squares" are end-grain balsa, really cuts down on the weight of the boat.  In many cases, they were small squares glued to scrim cloth, pretty much allowed the coring "panel" to conform to crowning in the cockpit sole or wherever, like cabin tops...

On occasion, we would run out of balsa and decks would be cored entirely with marine ply.  The first thing we did in the morning (0600) was bring in the decks and hulls that came out of cutting over night.  Boy, could you tell when a deck was cored with ply...heavy sumbitch!!

[jsakat1]

Thanks for the info. The good thing is that the fiberglass sole under the balsa core is pretty much intact. I can lay the new floor on it, after putting some mat ln the old sole without cutting the mat out.

[jsakat1]

Going back to it mine had marine plywood cut up in tiles like 4x2 (red wood). It had balsa on the core which is lighter and more spongy looking and on the sides soaked up the resin pretty good. Is the plywood in that arrangement common?

As for the new deck, after prying off the plywood squares, I have sole leftover left. I am going to sand that down, reinforce with mat or woven and put divinylcell as my floor.

[LilRichard]

You're saying you have fiberglass left after prying the wood off, right?  Why would you leave that?  You're better to take it out, see how your stringers are, then put down a complete new floor.  You would be hard pressed to get that remaining glass to bond with your new core completely...

We need pics though, diagnosing this via description is close to worthless.

[RickK]

Maybe he's talking about flipping over what he cut out, prying the squares off and having a skin left, like re-backing a fuel tank cover?

[jsakat1]

Will post pics this evening

[jsakat1]

http://www.facebook.com/photo.php?fbid= ... =1&theater


This is a picture of the floor with the top sole removed

[slvrlng]

If you had a small area to do using the divinycell might work okay. Since you are this far into it I would agree with lilrichard and say you will have a huge problem getting it (or anything else) to seat into the old underlayment. After using the divinycell on my hatch repair it is extremely important that each screwhole is overdrilled and filled with epoxy and cabosil mix as divinycell has zero strength for holding screws by itself. Make sure you wallow out the bottom of each hole so they taper up towards the top. When filled this makes it just about impossible for the screw to pull the epoxy plug out. DIAB recommends at least 1/8" beyond the threads on the screw.