Cheap raft

I have a piece of plywood big enough for two people to sit on comfortably. After surveying various options (including styrofoam) that seem rather expensive, I realized inflatable mattresses are pretty cheap. Would a raft made of a few mattresses strapped to a piece of plywood work? Such floatables don't seem very durable. Perhaps I should protect them with a tarp or some such underneath?

The raft doesn't need to be safe; I go swimming in this same place all the time. But it would be nice if it was half functional.

 

Or you could put the plywood on the bottom.

That would make it more durable.

Any access to logs in your area?

Old power poles?

Thses make great rafts.

-Tom

 

No access to logs. An no place to store the raft if it were made of logs. I would put the plywood underneath, but that would defeat the purpose of having something dry above the water.

 

get some old inner tubes from trucks and tractors, usually for free from local tyre repair places. get them patched up, inflate them, then rope them together. Some hole in the plywood, tie the plywood to the tubes

voila - reasonably robust, cheap floating transport

 

This is not -quite- as cheap as what the OP wanted, but anyway-

You can often buy used plastic drums very cheaply from companies that manufacture food. They may even give them away--but many recycle them now, so they may charge a bit of money for them.

All kinds of companies that use liquids end up with these things, but taking them from just anywhere can be risky. If you get it from a food company, you can be sure that whatever was inside, wasn't toxic.

Two good places to try asking is any local soda-pop (like Coca-Cola) and beer bottlers. The 55-gallon [200 liter] ones can be tough to use (cause they're so fat and they float so high out of the water) but the 30-gallon [120 liter] ones would work nicely for a small swim deck.

The USA 30-gallons I have are about 14" diameter and 25" tall. The capacities of these containers are fairly-well standardized worldwide, but the shapes aren't.... so don't draw up plans until you know exactly what you'll be working with.

These are HDPE plastic so you need to shield them from UV, but otherwise they're pretty tough and an easy starting point. Ask for "closed top" drums, and be sure to get the lids with them.

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If you want to get new ones--or just find out the cost--look in the local phone pages of the nearest big city for companies that sell "containers".
Example:
A couple years ago I wanted some 30-gal drums for drinking water storage. I didn't want the water to taste funny, so I had to have new drums.
....The cheapest survivalist places I could find online wanted around $47 each plus UPS shipping, which bumped the price up to $65 or so.
....A local container company sold me ten them off their dock for $220. I didn't really want ten, but they had a minimum $225 order limit. So now I've got six I haven't needed for anything.... yet....
~

 

The cheap air mattress thing should work if you can find a way to hold the air mattress to the plywood deck so the mattress is held in place out flat. Perhaps use duck tape or packing tape and after you have them inflated wrap the tape all the way around the plywood and the air mattress to hold them together. If the air mattress has a large edge margin you could tack or staple the mattress to the plywood through the edges (outside the air tight seam).

If you are good a scrounging stuff you can save the money of even the air mattress by using the 1 gal plastic milk cartons. Some guy sailed a raft (he called it a boat) to Hawaii from California made from plastic milk cartons. You can drill holes in your plywood and lash each milk carton through the handle to the "deck". The one liter beverage bottles work good too. Get the kind with the thread screw-on cap rather than the pop-off type, they stay on better. Each gallon milk carton should give you about 60 lb floating capacity each, lash them around the perimeter of your deck. figure about double the max capacity: if you want to float 250 lb worth of people on your boat, assume 500 lbs float capacity, or 8 one gallon milk cartons.

Good luck, have fun with your "red neck" boat.