Small open ocean craft

Good morning fine people. I have a small issue I would like some advice on. I am currently stationed in the gulf of Tadjourah, a nice calm little pocket just north of Somalia. Boats here are old, expensive, and tend to sink. I'm of the opinion that I should grab some local aluminum sheets and stitch up a small craft to go out to the small islands we have a couple miles off shore.

But there is the rub. This would be my first boat, and although I have a plasma cutter in hand, I have no idea of what could reasonably be accomplished. What I'm asking is if anyone could provide a little guidance or direction on the designs for a small craft for the not quite open ocean, powered by a new 6 hp suzuki, to get myself and small family around in fair weather?

 

So, it looks like a runabout, 12 feet in length, about four feet across and with a hard chine. Should be easy enough to fab up, but can one design this to be an origami vessel? Perhaps we can see.

 

With an outboard motor of 6 horsepower I would suggest that a dory style boat would be suitable.

 

What I've wondered is why the locals all use Dhows. First, there are no trees in this part of the world, thus getting the materials would be expensive. Second, what's up with the excedingly high prow?

A dory should be easy enough to construct out of flat sheets. I'll have to swing by the local 'home depot' and see just how big a sheet of what metal they have. We will see if I'll be limited to steel only.

 

Bigger than 12 ft.
Length means higher speed with low power (research: hull speed). 6hp metal boat with family is not planing so length is main factor for speed.
Length also means safety from the larger size. Its not that simPle but in general you always want bigger boat than you think. Especially true to amateurs. 12ft is tiny for more than a dinghy.
Alu is not ideal material for small boat as the plate stiffness and strength work better in larger scale. You will end up with relatively floppy yet heavy boat. Just something to be aware of. Read more about alloy small boats here there have been some good threads.

 

My dim memory seems to remember that the Dhows are largely built in India, and occasionally some parts of the southern coasts of Africa.

"Despite their historical attachment to Arab traders, dhows are essentially an Indian boat, with much of the wood for their construction coming from the forests of India."

http://nabataea.net/ships.html



The high prows got popular for the short, sharp waves around the Gulf - you don't get the big rollers in those windy season blows.

"during shamal events generate high waves in the northwestern Arabian Sea,
which propagate as swells in the NW direction and reach along the west coast of India. The potential swell generating areas are the Gulf of Oman and off the east coast of Oman. The significant wave heights associated with
shamal events reach above 3.5 m in the northwestern Arabian Sea"

http://drs.nio.org/drs/bitstream/2264/4218/1/HYDRO-2012_109.pdf

I seem to remember that the Indian Ocean near the NW corner is virtually unnavigable for small or low engine powered boats for 4-6 months of the year.

 

Ah, hull speed. Having played only on sunfish in the lake before, I have no frame of reference as to what a 6hp motor can actually do. It certainly didn't sound impressive, even if they weigh 60 lbs.

 

punkerddo you can ask Jeff Spira if you can scale down this boat. He answers quickly and honestly the e-mails.http://spirainternational.com/hp_labr_a.html
Whith 6hp you can go very safe in a dory 18 feet, more or less.

 

I had stumbled upon his site a few days ago. Seems a decent route to try. I'll post if he is willing to scale down the design.