Homemade Tarp Boat

[septiroth0]

Hi, my cousin and I are starting a project to build a boat of tarp around a wooden frame. I have several questions because we are inexperienced at boat building.

1.How should the tarp be connected?
2.How should we waterproof it?(Tarp seams and Wood)
3.What is the best type of wood for the lowest price that could be found at Lowes or Home Depot?
4.How wide will it need to be so it won't capzise if the length is 12ft?
5.How high should it be?

Our boat will look somewhat like this <====> and its dimensions will be

Length=12ft
Width=?(Thinking about 5ft)
Height=?(Thinking about 3ft)

We are thinking fo building it so that it will fit two six foot or taller people comforatably. We are going to use a tarp shell which will require around 90ft of tarp with our estimated dimensions and around 50 to 60ft of 2x4 lumber (not exact). We expect it to take several months to raise funds for materials.

[tuantom]

How much horsepower?

[alan white]

1.How should the tarp be connected?

What is the tarp going to be made from? The cheap tarps are pretty fragile and don't glue all that well. Tar sticks to them, so I'd suggest sewing the seams and then tarring the seam after.


2.How should we waterproof it?(Tarp seams and Wood)

Same answer.


3.What is the best type of wood for the lowest price that could be found at Lowes or Home Depot?

Make longitudinal pieces about 3/4" by 1" using straight-grained fir.


4.How wide will it need to be so it won't capzise if the length is 12ft?

Three feet. Better get used to the idea that this is probably gonna be a canoe. Why tempt fate?

5.How high should it be?

12-14" depth amidships, 16-18" at the ends. Same as a canoe, if it is one.

I'd sew it every few inches by hand and then use a machine and zig-zag stitch it.
Sounds like fun.

Alan

PS There are other ways to do it of course...

[duluthboats]

If this is not a joke. Please, do a web search for "skin-on-frame" boats. There is alot of info out there some of it is good. After that if you still have questions we will be glad to help and you will have more detailed questions.
Gary :D

[rwatson]

Hey - I've built 'tarp' boats!

The trick is to use a cotton based fabric.
If you can afford waterproofed fabric (like a trailer cover) , by all means use it. If you cant, get 10oz 'duck' from a fabric shop.

When you put it over the frame, wrap a length of timber near the edge, and wind the wood around and around to create tension on the fabric, before you nail or staple the fabric onto the frame. Ask an upholster to show you if you are unsure. You need a tight, stretched fabric application to stop it bulging in when you put it in the water.
The frame should have no more than .3 square metre of unsupported frabric area at a minium, but even more support is better. The ultimate is to get a wood matrix frame with a minumum of around 6" square of support from the frame.

To waterproof the fabric, goto a hardware shop and ask for some kind of light bituminous black goo that they use to waterproof the inside of water tanks.
Its longlasting, and very effective. You can get non petroleum based mixtures which are less smelly but just as effective. In Australia 'Pabco Hydroseal' was one trade name.

The dimensions you suggest are a bit unwieldy. Go for 16 ft long, 2 feet deep, and 4 ft wide. It will be easier to paddle or power. You have a large fabic covered canoe basically. Lookup a few canoe designs in the local library to get a 'feel' for shape and form.

Use long thin 3/8" by 1 - 1.5" strips of bendy wood over plywood (marine ply of you can afford it) frames. Paint the frame thoroughly before the fabric is applied.

You will have a ball, and get a lot of fun out of the process. A cheap way to start experimenting with boat design

[PAR]

Your boat should look like this before it's skinned.

http://www.duckworksmagazine.com/08/projects/transail/DSCN1072.jpg

This is a sailing version of what you've described, but didn't have to be.

There are lots of plans available ffor these types of boats, I'd strongly recommend you get one.

[rwatson]

Hi Septarowith

Pars picture is exactly what you need.

Dont be scared of building from plans. It will actually save you money, even if you have to pay for the plans. Even if you dont get the building exactly right the first time, it will be a whole lot better than making it up yourself.

I remember being young with no money, but a real urge to get afloat. I started off with a couple of pine boards that had actually fallen off a truck (really, they were lying on the road). You will be surprised how cheaply you can get afloat.

Start asking around for the price of stuff now, so you know how much you have to save. It will all happen sooner than you think.

[septiroth0]

How much horsepower?

We are using oars. We want this to be as close to man made and man powered as possible.

[septiroth0]

rwatson I was planning on using this kind of tarp. It wil probably be heavy duty.
http://stormprepare.com/images/tarp_light.JPG

It will look somthing like a cannoe.
Here is a 5 min drawing of the top down in paint.
http://i169.photobucket.com/albums/u233/septiroth0/Untitled.jpg

[dragonjbynight]

Poly may get you out for a time or two, but weather (sun in particular) tends to make poly "unravel". If you are planning on using it several times, I would go with Mr. Watsons suggestion.

[Landlubber]

We used to make kayaks from cheap canvas and simply painted the canvas with enamel paint, they last for many tears of reasonable work.

We also made canoes from sheet tin, 4x2 bow and stem posts and tar for the seams, they were great, but my next door neighbour would shoot holes in the bow and sink us, it wa all good fun then.

My how times have changed.....

[dragonjbynight]

off topic, but Par, do you happen to have any plans for that canoe or one like it that you might be able to forward to me, that looks like it would be a fun start

[alan white]

I would agree that blue tarp is not too reliable a way to skin a boat. However, at Home Depot and I'm sure Lowes also, you can buy painters drop cloths for not too much, They are cotton and I've got a couple and they're pretty tough. You wet cotton to stretch it and then when it dries you can paint it with an oil based paint. The paint strengthens the fibers in the same way resin strengthens glass cloth.
Your drawing shows a strange angle change in four places. That isn't how to do it. It's easier to bend the long sticks into curves. Get a plan. Google "Geodesic Aerolite (http://www.boatdesign.net/cgi-bin/bdn/jump.pl?ID=280)" for ideas.

Alan

[Guest625101138]

off topic, but Par, do you happen to have any plans for that canoe or one like it that you might be able to forward to me, that looks like it would be a fun start

I have made a few hulls from light gauge aluminium. I have got the process down to a reasonable art so making a boat takes a weekend.

I have attached a rendering of a cat. The hulls are 3.6m (say 12ft) long and 0.3m wide. These hulls can be made very easily out of 0.8mm or 1mm aluminium sheet and ply for the deck.

The cat will be easily driven, nice and light (hulls could be easily separated for one person to cartop - each around 12kg) and stable on the water.

The hulls do have transition lines where the sheets meet but this makes very little difference to performance.

Rick W.

[PAR]

Dragon, contact me by email (click on my name) and I'll let you know what I've got available.

There a few different types of fabrics you can use to "skin" a boat like this. It's a tried a true method, producing a very light, though typically delicate craft. Dacron is the usual choice for durability, toughness and workability, but it's not the only fabric.

[rwatson]

Yes, the previous advice is correct - that cheap blue tarp will be useless! To hard to fasten to wood frames without tearing badly, and it will rot in the sun. If you want to prove it, nail a small piece of the blue rubbish to a wooden plank, and watch it rip as you pull it.

The painters drop sheets are an excellent idea, but you can get heavy calico from fabric shops cheaper, I believe.

That hull drawing is very unsatisfatory. Why have those ugly sharp angles at both ends? Its easier and cheaper to have a smooth flowing, bent timber hull than the weak and fragile arrow shape.

Carefully study the picture of the boat frame provided before

[ancient kayaker]

I am surprised to read tarp rots in the sun; it is made for protecting things like trailers that are stored outdoors. It made an adequate sail, mine lasted several years and died in a fire, but it was awful noisy. Unless you stretch it tight you'll never catch fish from this boat ...

What is your object, low cost (a short life but a merry one) or low weight or just ugly for the hell of it. I read somewhere about an adhesive tape for tarp that becomes permanent when exposed to sunlight, although I would want to test it before I used it. Tarp is hard to glue, been there, tried to do that. It sows well but the seams will leak. Nailing won't last long but you can try screws and battens. It'll probably work for a while; guys have even used food wrap for skin boats although it is usually only good for an hour or so.

As for me, I'm cheap and want low weight. I use marine ply now but my first few boats were made with door skin (1/8 luan) at $11 per sheet, good for a few seasons only but it allowed me to learn by doing and I never fancied skin boats. If you're the "can't learn from a book" type like me maybe that would be the way to go but inspect each sheet carefully as some of it is punk.

[rwatson]

The experience I had with that cheap blue tarp "rotting in the sun" was a length of it laid over a boat. I think the fact that it wasnt tied tightly meant that the wind was constantly flicking it about, and that result in frayed edges and where it contacted hard surfaces.
As a result, the "blue stuff" peeled off the white fibres, and the UV seemed to turned the white fibres into white fluff.
I think the "blue stuff" is UV imprevious, because there is still lots of it floating around the back yard, and it hasnt rotted!
Whatever the "white stuff" is, it doesnt seem to like UV.
In any case, I just dont bother buying it any more, as it is such rubbish.

[PAR]

All these plastic, loose weave type of tarps will de-polymerize in time, usually in about a year of continuous sunlight (here in Florida). The silver ones last about twice as long, but these too will break down from UV and after a single year, clearly show signs of breaking down. It doesn't matter if it's pulled taunt or left slack. If allowed to flog, of course fatigue will enter the mix, but UV will break down the polymer chains into the shreds we're accustomed to seeing.

[alan white]

I remember when you could only buy heavy cotton canvas tarps which had been treated with some concoction of cupric oxide (copper).
This is basically your common painters drop cloth, except heavier and with grommets along the edges.
I had one and it lasted for years. Holes were self-healing and they were heavy enough not to flog (which is what really kills plastic tarps, and what makes me wonder WHY anyone uses them for sails).
Now, despite the fact that China could easily bring back these high quality tarps, I don't see them in the big chain stores. I'm sure they do exist all over, but where are they?
I guess this diverges from the use of tarps for sheathing a boat, having more to do with covering a boat perhaps, but those plastic tarps are abyssmal excuses for what our grandfathers used all the time.

Alan

[dragonjbynight]

probably just cheaper to make and have a higher profit ratio.

[ancient kayaker]

I use tarp for small sails on smaller boats like a kayak because it's waterproof. Typically when sailing a kayak I spend half the time paddling and it's nice to be able to lower the sail, mast and other accoutrements and clear the deck. It's hard to keep the sail out of the water.

When you're that low in the water a sail that doesn't get soaked is a big advantage. I tried nylon, it set nicely and was quiet but weighed a ton after it ended up in the drink. Tarp is incredibly cheap and very light, however I like to have it all packed away before I get back to the marina so the real sailors don't get embarrassed.

Other than being noisy, the main problem with a tarp sail is the material won't stretch. I have to allow for that in the design so it will set OK.

[juiceclark]

Sorry I'm late:
I built a boat bunker using a fantastic tarp that was very cheap. People often use them for pond liners. You can buy used billboard signs on Ebay (guy sold me one from Texas). For $40 plus shipping I received a 15'x50' sign that is incredibly puncture and UV proof. This one has been under my boat in a FL canal for three years without a puncture.
The absence of flowing water under my boat prevents any growth. The tarp has a very slight positive buoyancy.
Tony in Sw FL
http://i246.photobucket.com/albums/gg120/juiceclark/IMG_0252.jpg

http://i246.photobucket.com/albums/gg120/juiceclark/IMG_0256_5_1.jpg

http://i246.photobucket.com/albums/gg120/juiceclark/IMG_0250.jpg