aluminum as floor material?

[Martian]

I have seen a couple of boat builds where people use aluminum because it is lighter....only a couple and they did not give numbers on how much lighter it was. Everyone else seems to use plywood.


My main concern is weight.
is the weight thing true? How about the support and feel under the feet.....so
What are the pros and cons of aluminum?

Martian

 

[Martian]

Re: aluminum as floor material?

It is amazing how google searches after a post work better than before

I found this bit about Airstream (those big campers) using aluminum for flooring: http://www.airforums.com/forums/f36/plywood-alternative-46500.html

Still wondering about the weight...I have heard it weighs 1/2 as much as plywood for the same stiffness....only unsubstantiated....still looking for the benefit of iboats experience.

My main concern is weight.

Martian

 

[Rickairmedic]

Re: aluminum as floor material?

Martian the only thing I can tell you about aluminum is one of my current boats was redone with it but they half did the job as far as I can tell so now I have to figure out how to get it back out of the boat so I can check the stringers and transom and foam and then refit the cap so it site right on the boat . I wont be putting the aluminum back in I will be using Ply so that if it needs to be done again as long as I own the boat it wont be half the job to do.


Rick

 

[Bob_VT]

Re: aluminum as floor material?

What are you working on? A raceboat? A bass boat? An ocean liner? The weight savings is tiny when compared to cost. I had an all aluminum bass boat made by Fisher before they were bought out by Tracker. It really was nothing special but I never worried about rot.

Aluminum picks up flex memory and tends to sag and stay that way.... wood does not. Aluminum flexes more too.

Why not try a lighter grade plywood covered in mat with epoxy or carbon fiber for lightweight strength.

 

[Martian]

Re: aluminum as floor material?

Thanks guys for the responses...

I guess I can always screw up a couple of plywood sheets...way cheaper than screwing up aluminum....easier to work with too.

It is a fishing boat and I am talking about a 2 2x4 ft sections and a 3x3 section.

I already have plywood 2x2 sections but was thinking I might replace them in the future.

Aluminum is about 4.5 times denser than plywoood (depends on plywood) and "x" times stiffer (10-15? I am guessing because 1/16th thickness is way to thin...I am guessing) but as was said...no flex so eventually it sounds like it will not wear as well.

So if I have about 40lbs of plywood the most I am saving is 30lbs or so according to my very rough math.

lots of guessing and rough math but cost alone can't be the only reason (its the flex thing) just about everyone chooses plywood.

thank you.....if there is anyone else that wants to post I think it is worth it because this info is not so common.
martian.

 

[halas]

Re: aluminum as floor material?

Did you try to price the aluminum?
I think it came down in price a lot in the past few years but you are probably looking at several hundred $ for what you need.

 

[Bob_VT]

Re: aluminum as floor material?

Why not just buy an aluminum fishing boat

 

[5150abf]

Re: aluminum as floor material?

$$$$$$$$$$$$$$

Theres your problem, aluminum is very expensive and for a deck you would have to go with at least 3/16, better yet 1/4 and a sheet of 4x6x1/4 is about$500.00, it gets smoking hot in the sun and conducts sound just like a speaker.

Stick with marine ply, there is a reason everyone uses it.

 

[J. Mark]

Re: aluminum as floor material?

aluminum has another drawback

Glue won't stick to it well, fiberglass won't stick to it.

So while it is lighter and stronger, it doesn't allow you to tad to the hull or glue to the stringers. You can use screws, but screws place loads on small areas and aluminum isn't a hard metal. Screws will pull through.

An aluminum deck has a certain appeal, but it isn't practical for consumer boats

 

[erikgreen]

Re: aluminum as floor material?

I agree an aluminum deck would be nice, but unless the rest of my boat is also metal I wouldn't bother.

Sure, it won't rot even if abused, but it can have other problems, and as has been mentioned it can create/add to noise and it's uncomfortable to kneel on.

You don't need quarter inch plate to make an aluminum deck, although it would be more expensive than plywood. I'd personally use something like 1/8" tread plate with an appropriate support structure of something like 1 1/2 inch rectangular tubing or channels welded together and lag bolted to the wooden bits of the boat.

It could be made to be lighter than the composite decking made from plywood and glass, and stronger, but if you really need light and strong go for thin foam or marine ply decking with carbon composite covering.

Attaching the aluminum to the hull sides would be a problem... you'd have to put in a wood cleat along the edges and screw/rivet the aluminum to it, and it still wouldn't be as strong as a glassed joint. Plus there would be hard spots and fiberglass failures anywhere there's stress because the aluminum would be very stiff and the fiberglass would flex around it.

If you must have a deck that won't rot, make one out of foam core and fiberglass.

Erik

 

[Navy Jr.]

Re: aluminum as floor material?

I have a fairly new aluminum boat, and it's deck material is ... marine plywood.