lightest flooring material.... (that actually works as well as ply may?)

[FNQCairns]

I am looking to add a platform (like a casting platform, storage underneath) up the front because of the lifejacket labeling requirement and for general usefulness, also it will allow better access to the in water anchor over the side which as my boat is reasonably high sided can be a problem to some...weight is THE TOTAL issue I am trying to confront here...every kilo added to the front of a boat makes the prop work hard harder..extra slip at cruise......completely stuffs fuel economy over any 150km day trip. If i built what I would like my daily bill might increase 15% (even)....so looking for 5%...none would be best though...not going to happen. I can build out of 1.6 alum angle for the structure and be very scarce with it...but even 6/7mm ply is actually heavy..I looked into tread plate..it was 2mm at its base....and even that added up greatly over my total dimensions. I am only guessing...3.5 m2 as the top side area. i got no idea but I live in Cairns which is regional..so a real problem sourcing products. any links or ideas to anything that might span an area supported underneath but light per m2 MUCH! appreciated.

[shaungonemad]

I just replaced the floor in my half cab with 3mm checker plate it worked out similar weight as the ply and will last forever you can get it in 1.6mm thickness but is very flexible. If you span the ply to far you may put your foot through it after a while. To do it properly it will probably weigh more than you want it to

[Fish Face]

Coosa Blue Water 20. Its a high density, Poly urethane foam panel, laminated with glass fibre. 12mm thick will be ample. Stiff, half the weight of ply and expensive !

[rtp1984]

So a search for thermostat-lite board.
Great gear. Not cheap, but exactly what you are looking for.

[rtp1984]

Sorry.
Thermo-lite board

[Chimo]

FNQ Consider 1.6 plate but sit it on an aluminium box tube support base. You can get thin walled box tube that is light too. Consider pop rivets as well as minimal welding but due to thickness and lightness you need a clever skillful welder. Obviously you can hinge the entry to get your jackets. An Al box as part of it can take care of anchor, warp and chain. If the box is deep enough it can also lend support to the platform too. There is also walk way mesh which will be light but still needs a box tube support system. http://www.ullrich.com.au/walkway.php Cheers Chimo PS Whats with the text insisting on running together?

[chocolatemoose]

quite a few plastic based boards. we use "seaboard" for heavy applications 12mm or ...ehh name escapes me.. half as dense as seaboard... about 350 dollars for 2.4mtx1.8

[scottar]

Seaboard Lite?

[bluefin59]

I have celuka board in my boat done by the boys at origin ,it's light it doesn't hold water fire proof and fuel safe . It's expensive and works great instead of ply but you need to secure it properly or it will curl a touch on free floating areas it's a little expensive as well but it is worth it as it's been in my boat 6 yrs and will probably outlast the boat ...Matt

[myusernam]

THERE HAD TO BE ONE...

ply

IT'S AWESOME

trim it up a bit

[juggernaut]

Carbon Fibre!

+1 for marine ply for weight and structural stiffness.

I've got some king starboard and some other reconstituted lightweight plastic which I've used on other areas of the boat (small panels and upholstered side pocket backing).

Both are far heavier than equivalent thickness marine ply and have nothing like the structural stiffness of marine ply.

[Rip it up]

There is a honeycomb product. Polycore. Most fibreglass suppliers can get it. $80 a sheet in 10/12mm. It will need to be fibreglassed on both sides. But stupid light. It floats on water. Never rots. And stiff.

Think of it like a Dundee of drinking straws held in your hand. Then slice 10mm off the tips. With a layer of glass either side.


You could step into carbon world but the benefit over a 1m square would only be 400grams if that.




Damo's dodgy boat building factory.

[tunaticer]

A mate fitted some plastic based decking in his plate hull. It expands differently to the alloy on a hot day and buckles badly, then settles down again at night when it cools. It cost him a fortune for all the decking and fitting it.
He pulled all that plastic up and replaced it with 3mm ally sheet with carpet glued on for an excellent result that no longer distorts or buckles during hot days. He says even on the hottest days he doesnt feel it get too hot for his feet. He used a light grey carpet to avoid heat absorbtion.

[The Woo]

Go to your local kitchen fabricator and ask to see some Nema board.
It's cheap as chips, water proof, stiff (but susceptible to punctures), and damn light.
Covered with carpet it could be just the ticket.

[Crocodile]

Hi FNQ,

What boat are you fitting the deck to?

The reason that I ask is that it may not be as adversely affected by weight as you might think.

Whatever you build will need some sort of framing.
It is only the decking that will change weight with different materials.
3.5 square meters of 12mm ply will weigh about 28kg.(3.5*.012*660kg, ply has a density of ~ 660kg/m3)
Very exotic and expensive materials may save weight but at greater cost and complexity.
eg, you could make it out of vacuum bagged balsa cored Kevlar sandwich and save maybe 10kgs at triple the price.
Put a 25 litre drum of water up the front, move some gear aft to balance the trim and see how it effects the performance.
PS as it is only a casting deck, no need to over-build, so what if it is a bit springy underfoot.