honeycomb as a boat floor ? good product?

[lembo]

Gday guys
Doing the floor in the sharkcat soon, was going to use 9mm marine ply glassed 1 layer on bottom and probably 2 ontop but was talking to a guy about honeycomb, its cheap and light and he said 2 layer underneath of glass 2 ontop of 10mm honeycomb the floor will be more solid then ply ? my cross members are 300mm apart so will I get flex over that span ?
And I read you can get different types of honey comb , Alluminum, grp,paper even marble surface ( its a Trojan fibreglass product if you want to look on there site) would paper or grp suit to put epoxy resin and glass over?
Is 10mm to thin ?
Anyone used this and give me some help and advice would be great.

[Master4Med2]

Lembo, just sent you a PM.

10 mm honeycomb is to thin, With the spacings of the cross over beams you will need to use 19 mm honeycomb with two layers of glass on both sides, ( double bias +45 /-45 600 gram ) .
Nuplex Composites has what you need.

Cheers
Con

[Noelm]

Just use ply, but thicker than 9mm,asy to work with, cheap to buy, glass the underside and seal the edges, mix up some bog and use stainless screws to hold it to the cross over beams, it will be as strong as hell and have no flex at all. When you glass the top, go up the sides to under the side pockets.

[myusernam]

12mm ply is the go. seal it, glass it well and it will outlast you. you have to still take a lot of care penetrating honeycomb etc.

[tropicrows]

Well there you go, 3 replies and 3 different answers. I used 19 mm ply over 600 mm centers and it was solid as. However honeycomb done correctly is stronger than ply and much lighter. Do your research, talk to fibreglassers who bulid boat/yachts.

[Noelm]

The material he is talking about is very good, probably much better than ply, but (in my opinion) it is not for the home handyman/one off rebuild

[lembo]

Thanks guys all replies and input are taken on board, the reason I'm trying to stay as thin as possible is my original floor was straight fibreglass and only about 7 mm thick and as im only replacing the rear deck and leaving the original floor in the cabin the rear deck will be higher then cabin floor so if I get water in my cabin it won't drain very well out the back deck, not a huge problem as its a rarity that water does enter cabin. The boat has big tanks and big outboards so I'd like to keep weight minimal. Was going to just go all 9mm ply with a few glass layers but after talking to salesman and other members honeycomb was recommended. Is it really harder to glass then ply?
Its cost is comparitable to ply.
All timber under the floor was originally 25 mm hardwood its out and I was going to replace with 19 mm marine ply which will allow me to have a slightly thicker floor then original but finish up at the same height.
Any ideas/input are welcome though.

[The Woo]

During our rebuild we took any remnants of wood out. Why anyone would put wood back in with today's products available baffles me. But to each their own.....

I'd id be using the honeycomb or a closed cell foam.

[Noelm]

In a way, I agree, but for a one off, if done properly (not like when it was new) timber will probably outlast the owner, I mucked around with some similar honeycomb material when I was building a lightweight casting deck on my tinny, and it was pretty tricky to work with, let alone doing a floor that is very hard to get in the boat in big pieces.

[myusernam]

well i used marine ply in my floor back in 2000. i have recently had sections up to fix a tank and line issue. it's like the day it was done, as with the stringers. The old production boats were crap timber barely tacked in place with no thought for longevity. even the poorest prepared timber will outlawst the warranty period which is all that was cared about. any core material will suffer from water ingress. just do it right. ply is easy to tool and very strong.

[The Woo]

Yeah ply can last if it's sealed up tighht and is very dry to begin with..... and besides, I'm probably not the right guy to ask..... I'm of the belief that if it's worth doing, it's worth over-doing :p
That's probably why we're currently making a carbon fibre hardtop where a solid fibreglass or ply cored version would have sufficed. But hey, we're saving many many kilos from the right part of the boat.

[Rip it up]

I'm a big fan of the honeycomb products. I used a 10mm section for my floor in he little creek boat. And 15mm stringers. 2x20mm transom.
Single layer of 450 double bias and epoxy for the floor top and bottom.

No more rotten timber for me.

The spacings were 450mm apart -1000mm between bulkheads. All supported on the 15mm edge of the stringers. No cleats.

Yes it's difficult to screw fittings into. But nothing a little bit of planning can't fix. Epoxy filler plugs in the fitting location with sort that out quickly.

The professional builders of custom boats are using the honeycomb products more and more. Because it is light yet surprising strong in compression and shear. Creates a very stiff panel.

I have put 350hrs on my honeycomb floor. No cracks, no flex when jumping on the floor on the trailer. Handles the abuse of a crabbing boat and eskies etc.


Damo's dodgy boat building repair shop.