Inflatable composite flooring

[Big Mark]

Hi,

I apologize if this subject has been addressed before, but I couldn't find anything by doing a search.

I am looking to replace a plywood floor in a inflatable (really an inflatable pontoon boat). I want to reduce the weight and would prefer to use a type of composite material, perhaps PVC, etc., that comes in a tongue and groove like fashion. Similar I guess to the new composite planks I see people using for their decks. I know that some inflatable manufacturers currently use them in their "roll up" style boats, but I haven't been able to find a supplier of this type material. I would need to cut it to meet my needs, so purchasing a pre-fabricated floor just wouldn't work.

Any ideas as to who might sell this type of planking/flooring? White would be best, but color is not overly important. Hollow would be better than solid to reduce weight, it won't be supporting much weight.

Anyway, thanks for any help you can provide.

Kind regards,

Mark

 

[canada_bob]

Re: Inflatable composite flooring

If it's weight saving you're looking for and tough stuff then you might want to consider using closed cell foam, wrapped in a couple of layers of fibre glass.

I've made a couple of these over the years and they work well, once you have figured out what not to do that is.

I've used polyethelene closed cell foam panels, standard size is usually 8ft x 3ft x 1.5 inches.

Here's a link to the sort of stuff I use...

http://www.closedcellfoams.com/polyethylene.html

The first one I made copied the style of the wooden & aluminum floors, in that I laid them in sections across the boat, bad idea, seemed good at the time, but try coming off a wake or a wave at a decent clip and you'll find they crack open, but that don't happen if you lay them up length ways, two pieces attached to a flexible wooden spine that runs down the centre / keel of your boat.

The decks that I made were essentially surf boards that slipped inside my inflatables, easy in, easy out, just make a nice radius all around the edges.

Depending on the size of your boat you can come in with a "slipper" {as I call it} weighing less than 30lbs, depends on how frugal you are with the gel coat.

The closed cell foam that I use is the 2.5lbs / ft, so there's no weight to speak of in this stuff.

I've used birch for the spine, nice and flexible but also strong, I router it to a sort of inverted T shape, the base of the T being around 8 inches wide, the upright of the T being 1.5 inches to match the thickness of the foam, and the shoulders of the inverted T being 4 inches on either side, hope I'm describing this well enough for you to folllow...

You can shape the top of the T so that it has a V shape, that can help. If you are good laying stuff up you could use a heavier grade of closed cell foam, say 6lb grade, and make the spine from that, save a few lbs there.

Although closed cell {or any other foam} doesn't have much {if any} structural strength it's the fiber glass that gives the "slipper" all the strength you'll need.

Have a look at how surf boards are laid up, what they use, from solid balsa to honeycomb sections, but I've not come across anything cheaper or lighter or easier to work with than these closed cell foams.

Another little thing you can do to save weight {and money} is to gel coat the bottom and the sides, but not the top {the deck} when your slipper is finished just glue a 1 inch {or less} layer of closed cell onto it, makes for a very comfortable ride.

One thing about the "slipper" is, if the worst comes to the worst and your inflatable boat gets ripped open from one end to the other, just pull the slipper out and ride a wave home {my slippers each have over 200lbs of flotation}.

 

[Big Mark]

Re: Inflatable composite flooring

Hi Canada Bob,

Thanks so much for your help and the link, very much appreciated. The problem is that I'm down here in Central America and getting my hands on that would be difficult. As well, I really don't need too much, just enough for a floor that would measure 30" x 106".

I'm going to keep searching, I'm sure something pre-fabricated would work, rather than have to prepare something myself. I just need to find a lumber yard, marine store, deck/patio manufacturer, etc. who sells lightweight pvc/composite planks that can be cut to size. Either that, or I'll purchase some high quality trampoline fabric and use that. It's super lightweight and strong, but woudn't offer the rigidity of a solid floor.

Anyway, thanks again.

Kind regards,

Mark

 

[canada_bob]

Re: Inflatable composite flooring

Central America ? where about's Mark ? chances are someone will stock it...

Closed cell foam is sold near everywhere these days, it's also easy to ship and the 8ft x 3ft 1.5" foam rolls up not much bigger than a camping mattress.

By the way, you don't have to buy it in commercial quantities, you can buy a single sheet, which according to your dimensions would just about cover it, cost should be $20 to $30.

Canada Bob.

 

[Big Mark]

Bob - Re: Inflatable composite flooring

Bob - Re: Inflatable composite flooring

Hi Bob,

The problem is that when I add the fiberglass to it I'm not sure it will weigh much less than the plywood I have glassed over, which wasn't marine grade plywood, so that wasn't too heavy to start with.

Along with cutting down the weight I'm also very focused on portability, and I really don't want large slats of wood as a base, they're too heavy and difficult to carry/move. That's why I really like these pvc slats that are hinged together by cloth. I'm quite sure they weigh less that wood and are very stable, fine for standing on. They must be since I see them installed on roll up inflatable boats.

Every use this stuff

http://www.kingstarboard.com/Products/StarboardXL.aspx

Regards,

Mark

 

[canada_bob]

Re: Inflatable composite flooring

Hi Mark...

It's not the fiber glass that adds the weight, or the resin for the most part, it's the gel coat that adds most of the weight, but...

There's probably a way around that too, seeing as there's no structural strength gained from the gel coat, you don't really need it at all.

The next "slipper" that I make will be fiber glassed and then I'll just sand it smooth, paint it, then sandwich it top and bottom with the rubber runners that I mentioned in the "Works for me" thread. That way it will come in cheaper and lighter than using gelcoat.

As for the edges I have been thinking of using that foam pipe insulation, the stuff that's split down the middle. That would make for a nice "finished job" look about the project, you wouldn't see the "inner core" at all, and any rough spots you miss would be totally covered.

As for the weight vs using plywood, the rule of thumb if I remember correctly is, taking an 8ft x 4ft {standard sheet}, if it's 1/4" thick it will weight 25lbs, maybe a 15% more if it's marine grade.

If it's 1/2" thick you're looking at 50 lbs, 3/4" sheets would come in at over 75lbs, and so on, each 1/4 inch {of an 8ft x 4ft sheet} adds at least 25lbs to the weight.

The closed cell foam that I use is the 2.5 lbs per cubic ft, a sheet of that measuring 8ft x 4ft x 1.5 inches would weigh slightly less than 10lbs, that's 15lbs lighter than using 1/4" plywood. But this is before you add the fiber glass and the resin, which will be less than 15 lbs anyway.

So it would be almost impossible to compete with the closed cell stuff if you use plywood, even the 1/4 inch stuff.

Put it this way, plywood weighs some 15x more than closed cell foam, before you "wrap" it, that is.

Foam is way cheaper too, easier to cut {think box cutter or bread knife}, easy to sand down/shape, and so on. But the big difference is the weight, and as mentioned, if the worst comes to the worst you have a surf board {of sorts} with on average 200lbs of flotation in it, something you could sit on and row ashore

I hear you on the portability thing, I can't get my "slippers" into my Altima, they are too wide for the trunk, but...

They fit real easy on a roof rack, no weight problem there, and not all that long, easy as carrying a shortish surf board.

As for folding decks, Pas Moi, panels can be a headache putting them in, and getting them out, struggling with that and a session pumping can spoil what could have been a decent days fishing.

I like the look of that King Starboard though, that looks as though it's strong enough and light enough, no need to do any glassing with that, the weight could come down even further.

I'll check this stuff out, should be easy to shape, and easy to stick a rubber runner or 1/2 inch of closed cell to cushion the ride and give some grip to the deck.

Re the cloth hinges, won't they let the panels wollow ? mind you, in your case with a pontoon sort of thing the panels may not come into contact with the water ? in that case cloth hinges would work well. You would have to attach them in a Z {top of one panel to the bottom of the next} otherwise your third panel wouldn't fold up.

I'll go look at that King Starboard again, I like the look of that, long as the tensile strength is up there...

Hmmm, just had a look and if my calculations are correct this is HEAVY stuff, coming in at almost 60lbs per cu/ft not much flotation there, too heavy for me and my SD365.

PS... Central America ?

 

[Big Mark]

Re: Inflatable composite flooring

Hi Bob,

Yeah, I'm down here in the country of Panama.

Reducing the weight would be helpful, but it's really secondary. My priority is portability. Right now I have to large wooden(fiberglassed) floors that probably weigh close to 80 lbs together. Even if I were to cut that in half by using the foam it wouldn't make much of a difference in performance, and I'd have to re-fiberglass a new floor, which I don't want to have to do. If I can't improve portability I might as well stick with what I have, luckily I have access to a pickup truck. I will probably go with the trampoline material, but some sort of hard floor would be preferred. I know what I'm looking for exists, I've seen it in Apex inflatables. I just need to find it and purchase a 10-20ft strip of it and cut it to size. It's tongue and groove, so putting it together would be real easy.

Take care,

Mark

 

[Big Mark]

Re: Inflatable composite flooring

Hi Bob,

I think I'm on to something different, but real good. I might take a while to find out, but I'll post something when I know more.

Mark

 

[canada_bob]

Re: Inflatable composite flooring

Panama hey, just curious as I have a couple of buddies in Colombia.

Re the project that you're working on, any chance you can post a couple of photo's of the boat ? or send a link to the manufacturers site, just so that we can see what needs to be done.

Canada Bob.

 

[dobbs571]

Re: Inflatable composite flooring

I work fo a fence co there is a PVC borad for privancy fence that is 6in wide tounge and groved its about 5/8 thick and holow in side it comes in 8 and 16 ft leanghts I think . I weight 200 and have used scrap pc that we have and it held me fine i think you said some thing about 30 in wide if there is sa brace in the middle of it it would work grate waights a lot less that wook

 

[canada_bob]

Re: Inflatable composite flooring

Mark, does the decking that you're looking to make come into contact with the water, or is it a suspended deck like a Hobie Cat ?

If it's suspended and therefore not being pounded by the waves then T&G may be fine, but if the deck takes a beating from the waves then don't count on T&G unless the sections are held together by side runners similar to what we have on our inflatables.

Canada Bob.

 

[Big Mark]

Re: Inflatable composite flooring

Hi Bob,

No, it's off the water, but if the water is rough then it might splash up against it. There is a frame made of aluminum tubes that connect with each other, and the wooden floor rests on top of that. But, the 1/2" plywood when glassed weighs quite a bit, and it was for that reason that I was looking for an alternative. I just posted a question on the sailing forum about trampoline fabric, as that would be the lightest of all possibilities, but not as stiff of a platform as a wooden floor. As always, it's a trade off, I'm just trying to see what will work best. A roll-up trampoline floor is really appealing, as the tubes don't weigh much, nor do the aluminum tubes, so transporting it will be a breeze.

Regards,

Mark

 

[canada_bob]

Re: Inflatable composite flooring

I'd go with a trampoline Mark, can't get lighter than that, not as hard on the bones either compared to a hard deck, and real easy to stow.