How big a sail and keel do i need?

Obviously.

Obviously

We're all nuts. Some moreso than others. I am a rational individual doing some preliminary research in what is involved. I havent commited to anything and if its unfeasible i will abandon the project. Early stages yet and am not rushing anything.

I wasnt asking for the exact dimensions of keel and sail, just where i could find the info to find out in hope of a book on rule of thumb design. And thats what i got, i have ordered the book and will read it. I have a degree in computer science and consume books like an animial and dont think the knowledge i require will be hard to obtain or be beyond me.

I think i can handle a stitch and glue 8 foot hull after reading several books and asking a dozen or so questions. Its an 8 by 5 box with a pointed end, v keel and small sail to get to my max hull speed which will likely be between 2 and 3 knots.

The wind would probably blow me at 1-2 knots without a sail anyway and going upwind is likely not possible so minimal sail will more than likely be required.

A week or 2 more of basic questions then you will be viewing my rhino and cad designs then a blog of build progress

If i annoy you that much, dont read my posts because listening to you calling me an uneducated noob everyday will quickly wear out my tolerance.

 

Don't take it the wrong way Stonedpirat, PAR is just telling you that you will have not all the answer you need or want, and your thread will get silent (so to speak, a thread silent, bizarre) and will fade away quietly.
Do your work, don't rely on computer but on model. It is the best for a 8'.
And take picture of the model, put on your gallery for us to enjoy, and built the boat.
Should be done for Easter sailor.
Cheers
Daniel

 

Will do

 

5' sounds like a lot of beam for an 8 footer. Look at the PDRacer (lots of web sites) for clues how to design a simple fun boat; it has 4' beam. You can stand and walk around in one.
Lots of PDR's and clubs in Ozville incidentally. Not the prettiest boat though.

Don't use ballast. Small boats capsize all the time especially as the pilot gets cocky after a while. Ballast will ensure a capsized boat vanishes into the deep. Know how to get it back up again in the depth of water you plan to visit.

A "fresh breeze" of 5 on the Beaufort scale will create "moderate waves with many white foam crests" and be all you will want to handle or perhaps a bit more. Such a breeze will push a vertical flat surface with a force of up to 2 psi, but in practise for a typical sail is about half of that. On a 40 sq ft sail with it's center of area say 6' above the surface and the keel's center about 2 ft below for a total moment arm of 8' that's about 320 ft-lb of torque which you can just balance by sitting on the gunnel. By this time your boat will either be planing or raising a bow wave at elbow height, in other words, all you will want to handle until you develop some serious skills. Note that such a short boat is as likely to trip over its nose as it is to flip sideways.

You might want to start with a smaller sail say 30 sq ft until you have confidence in your hull’s design to carry more. An adequate sail can be made from a tarp: there are several web sites on this.

On a small lake with a proper PFD and sensible precautions you can't go far wrong, assuming you are halfway fit and agile, and even if you screw up royally and swim back to shore leaving boat bits in the water you will learn and the cost of materials for such a small boat is very little.

I'm not saying you couldn't do better by buying plans, in fact you probably will, but have fun, live your dream, and recognize you are taking a risk so be careful.

 

Hey Stonedpirate,

I'm also a software engineer that built a small boat, so I can relate to where you are coming from.

Definitely buy Richard Gerrs book, The Nature of Boats. It contains most of the important concepts and some equations to get you going.

My advise concerns your building skills. Unless you have good experience working with wood and associated tools like table/circular saws, planes, rasps, drills, etc., I strongly suggest you build your first boat from a plan.

I lacked the skills mentioned above and even though I built a simple boat from instantboats.com, at times the frustration was almost too much. If at the same time I had been trying to correct design flaws, well I doubt I would have finished it.

I believe you can eventually design and build a small boat that you will be happy with, but I do suggest you start off a project without the steep learning curve your own design/build would have. That way you will be more likely to enjoy your first effort.

Good luck whichever path you take.

 

That's Dave Geer, GTO, Richard is an actor I think.

 

An "Officer And Gentleman" or an "American Gigolo" :?:

Poor Dave, he must miss the money he can have done with a different first name

 

?????

 

Quote:
Originally Posted by PAR
That's Dave Geer, GTO, Richard is an actor I think.


LOL. Well he only has 3 books I know of - Dave, not Richard. He needs to write a few more so I'll have a better chance of getting his name correct!

Thanks for the proofreading! I might try that one day. :idea:

 

I was an officer and a gentleman, once. Funny. The ladies weren't as impressed with a backseat bomber puke.

 

Stonedpirate; If you really want to build and use a boat, forget about doing your own design work. There are so many proven designs out there that it is senseless for an amateur to attempt improving them. (we yankees call that practice "shitting in your mess kit") Plans for proven designs are cheap and plentiful. Some of them are in Oz and NZ.

 

We call it "shitting in your own nest "

 

Peeing in your own water bowl . . .

 

Stonedpirate: Here in Canada we just say "give it a go mate" - same as Oz.

 

So, on an internet site called BOATDESIGN.NET the advice given is to NOT design a boat?

Interesting.