Ok, now don't laugh...

[PatrickUSCG]

After reading all the comments from highly skilled craftsmen and sailors here, this is a little embarrassing, but my need is greater than my pride, so here goes.

I have to do a lot of traveling, so I needed a boat that I could fit into a suitcase and weigh in under 50 lbs so I can check it on flights. My fourteen year old son loves to fish, so when dad shows up every two weeks, so must the boat...

Ok, so here's the thing. The boat, something most of you guys have never heard of (or would probably care to) is a Sevylor Fishmaster; LOA: 10'3", beam: 4'2" inflatable, (If interested, you can Google image search it -there are tons of pictures on the net) something most of you guys wouldn't even use for a tender. But my boy loves it. It's basically a near-military grade blow-up raft. I've used several versions of their boats over the years in one application or another, and they're super-tough. But what bugs me about the craft is flex.

"Dude, it's a blow-up boat." I know guys, but it's what I have to work with.

I can only put a pound and a half to two pounds of pressure in it to stay within safety limits (to allow for pressure increases due to sunlight/heat expansion), so super-inflation is out.

What I want to do, I think, is pretty simple; fabricate a solid floor. For portability, it has a roll-up layered vinyl/nylon-cloth/rubberized floor reinforced with several 1/4" marine-ply slats about 5" wide, spaced about 5" apart. Which means that, like a sushi-roller, it's rigid side-to side, but flaccid as a noodle fore to aft. Keeping it portable is the complicated part.

I'd rather not use marine plywood because of weight, but also because I'd really like to devise a way to be able to break it down into smaller parts and stow. MP, as I recall, tends to do better in big, anchored chunks.

So in essence, I need an approximately 8'x3' (Only needs to be the size of the interior, inside the inflated rings), boat-shaped floor made of lightweight, water-resistant material that I can disassemble into smaller parts.

Ok. Let the hysterics commence...

Thanks guys, for any interest at all. We catch a lot a fish and an awful lot of mighty good memories in this little boat.

Patrick

[lewisboats]

I've seen corrugated plastic that is lightweight and rigid. If you were to cut pieces like a puzzle then glue them to something similar to a water mattress...with longitudinal air tubes that you CAN super-inflate then you can fold it up when empty. The plastic and the tubes will support each other.

Steve

[rwatson]

I own one of these Sevlor 'blow up' boats. I am not sure why you want a solid floor, but it shouldnt be difficult.

I know you think marine ply is too heavy, but it is the lightest way to get the strength for support of *any* material you can buy. Dont forget, you can get it 1/8" thick

You could make two panels that are smaller than the size of your larger suitcase for easier carrying.
Use readily available H shape plastic channel from hardware shops to hold the centres level when in the boat, or epoxy them together with some outdoor canvas material to form a hinge for transport.

Use a good quality marine varnish to protect the plywood from the elements.

[Rick Willoughby]

If you are paying a lot of money for a nice inflatable you should make a nice floor.

I am thinking of 6mm sheet of corecell or similar high strength closed cell foam. Cut to fit on the floor so it is a neat fit to the tubes all the way around.

Now epoxy on a layer of 180gsm fibreglass on either side of the foam.

Cut down the middle and each side panel into smaller panels of the required size to suit transport and then hinge the pieces with nylon hinges together so they fold up longitudinally and one hinge on the centreline on one panel pair. You will need to have some pins of say carbon fibre to lock the pairs together that are unhinged.

Make a scale model of the floor out of cardboard using cellotape as hinges.

You need to understand how it looks in under the tubes and also devise a means of pinning the panels crossways that cannot be hinged.

Other thing is to avoid any sharp corners that might wear on the rubber as it will eventually puncture it. You could place a rubber bead along the edge of the floor panels where they fit against the tube and the floor.

If you look around you might find an inflatable with folding floor. I have seen them years ago but cannot find one quickly now. The one I had used slide in nylon strips on mating edges rather than hinges.

You will be surprised at the strength for weight of a composite panel. Considerably lighter than ply for the same rigidity.

Rick W.

[CTMD]

You could build two floors, one with longitudinal folds and one with transverse. Unfold the two the two parts and join with dzus or similar half turn fasteners and it will become nice and stiff.

[PatrickUSCG]

Originally Posted by CTMD

You could build two floors, one with longitudinal folds and one with transverse. Unfold the two the two parts and join with dzus or similar half turn fasteners and it will become nice and stiff.

That's it!!

Heck, I could just leave the ones that are already there, (aforementioned spaced 5" slats) then just lie another set in on top attached with the fasteners. I like the idea of fabric hinging, and I'll definitely look into corocell or 1/8" marine plywood. The whole thing is covered in nylon canvas-like cloth, so chafing isn't a huge issue, but I like the rubber-guarding the edges anyway.

I think maybe if I make two or possible three staggered (center/bow, side/amidships, center/stern) sets that run longitudinally but are just long enough to overlap by 6" or so, and that either bolt together or use the fasteners, I can still make them short enough to stow. Awesome. Thanks so much! Safe boating!

[Lt. Holden]

Another possibility that I have seen are the roll-up plastic or aluminum camping tables. Try Cabela's or Bass Pro Shops. You could use two of them, cut them to the desired shape, apply a protective edging as previously described and hinge them together.

Stiff, high quality cardboard laminated between Tyvek or Kevlar cloth with a soft hinge and two (or more) sliding bolts is another option.

The previously mentioned high pressure inflated tube(s) could also be used to stiffen the assembly.

[Lt. Holden]

Another possibility that I have seen are the roll-up plastic or aluminum camping tables. Try Cabela's or Bass Pro Shops. You could use two of them, cut them to the desired shape, apply a protective edging as previously described and hinge them together.

Stiff, high quality cardboard laminated between Tyvek or Kevlar cloth with a soft hinge and two (or more) sliding bolts is another option.

The previously mentioned high pressure inflated tube(s) could also be used to stiffen the assembly.

[PatrickUSCG]

Originally Posted by lewisboats

I've seen corrugated plastic that is lightweight and rigid. If you were to cut pieces like a puzzle then glue them to something similar to a water mattress...with longitudinal air tubes that you CAN super-inflate then you can fold it up when empty. The plastic and the tubes will support each other.

Steve

Thanks Lt. Your post made me take a second look at Steve's idea. First though, I have to say the foldable table thing sounds like a promising approach to the second floor concept. My work is already half done with that route, all I have to do is basically lace on the other direction of the top-crust of the cherry pie. Or even just lay it over and fasten it. But Steve, I've been mulling over what you were describing, and I'm curious, but I don't think I'm following you. Are you saying (... wait! I think I get it!) like the old collapsible toy thing (I'm reaching here, stay with me, it might eventually make sense to me) where you push the plunger in from the bottom and the elastic strings inside the figure on top loosen up and it all "falls apart", only in this application it's an air mattress and the "strings and tension" are the high-pressure air and the structure is the puzzle-shaped covering? Dude, that sounds interesting. Imean, it may not be as field-expedient as what I'm thinking, but it's an elegant idea. Kind of like a military floatable bridge.

Or, I could be totally missing it....;0

Wow. Been reading some more here and there. You guys are hard core. I wonder what the wife would say to a "project" boat. Every old coastie should be entitled to one, right?

It'd be pretty funny if this 10' inflatable turned into a historically accurate square-rigger...

Btw, thanks for all the comments. A round of scotch for the house.

[Meanz Beanz]

Originally Posted by PatrickUSCG

I'd rather not use marine plywood because of weight,

Polycore and GRP or exotic? Light, stiff, maybe a bit thick... Just an idea.