Gaff rigs

[Paul Griffin]

I have just purchased an old plywood sail boat that only had the boom left over from the rigging; it's 9' long. I am getting 20' pieces of Dug fir for the new mast, boom and gaff. My question is how do I calculate the dimensions of each piece? The answer needs to be simple. The boat is 18'6". From the keel to the top of the deckhouse is 47.5", from the transom to the center of the mast opening is 140". I want to keep the boat on the safe side. (I have two small kids that will be sailing with me) some pictures of the boat are here http://www.langenstudios.com/wooden.html
I am planning on trying the Birds mouth spar idea.

This is a dumb question, but what would this kind of sailboat be called?

An advice would be great.

Paul

[Paul Griffin]

Here is the location of the pictures again.
http://www.langenstudios.com/wooden.html

[dld]

from the "Gaff Rig Book" by John Leathers it says the best proportions for a gaff mainsail with out a top sail is luff :1-0, head : 0.833, leech : 1.73, foot : 1.02, the angle of the gaff to centerline of the mast should be 30 degrees. Your spars would have to be longer by some.
:rolleyes: :confused:

[Art Read]

No such thing as dumb questions here, mate. What's "dumb" is muddleing your way through something like this half-assed by just "guessing" what "ought to work ok...." If I were you, I'd invest in Mr. Leather's book mentioned above. It's available through "WoodenBoat's" on-line catalog at this site's "homepage". More there than you probably need for your project, but it will give you a really solid grasp of the "whys and hows" of gaff-rigged sailing. I learn something new every time I look at it again. The good news for a "do-it-yourselfer" is that the gaff rig lends itself to making up a lot of the components yourself as opposed to a more highly stressed Marconi rig. You'll be spending a lot less money at the chandlery buying expensive bits of gear to make it all go. The bad news is that some of the stuff you'll need ain't gonna be on the shelf at "West Marine". It's still available out there, but you gotta know where to look. (This place will prove to be be a great place to start your search when the time comes.)

To answer your question about what to call her, assuming she's got only the one mast, (a pretty safe assumtion, looking at the pictures...) I'd just call her a gaff sloop. Can't help you with the design's name, but I'd be surprised if somebody here doesn't recognise her. (Unless she was a "one-off" designed by her builder?) Do you know anything about how she was rigged originally? Or do you just "want" to rig her with a gaff? Obviously, the "best" approach would be to try to reproduce the designer's original intention. If that's not possible, I'd buy the friendliest sailmaker I knew a beer after work one night and pick his brain a bit before cutting any wood. Good luck! She looks like a fun little boat!

[Greg H]

Here is a bit of info from 1856:
http://pc-78-120.udac.se:8001/WWW/Nautica/Rigging/UM856S65.html

[TCrisp]

Frank Hagan has a nice set of pages on the web.

http://www.messing-about.com/GaffRig/

[John B]

If you aren't going to have a topsail I'd consider peaking the gaff up a bit more. I'd go for about 18 or 20 degrees.

[wolfietuk]

I just recieved Leathers book and love it. It goes into a lot of history about what a boat is. Early on it was done by rig then by hull. Most smaller boats today are sloops. But you can call it what you will just enjoy.

Rick

[Mike Field]

Thanks for that reference to Frank's pages, Terry. He's a bit of a dark horse, I think. They look like an excellent resource.

Paul, the boat has rather the look of a Hartley TS18 to me (an NZ design,) although I'm afraid I'm no expert. JohnB (or others,) would you care to comment further?

[ 03-27-2002, 05:35 AM: Message edited by: Mike Field ]

[Bayboat]

Paul: Your boat looks very much like a "Buddy" design, IIRC published years ago in Rudder Magazine. The original rig was marconi, with a small self-tending jib on a boom. They were not particulary smart sailers, but with a gaff rig of modest area it should be nice for day-sailing with family.

[blisspacket]

Gaff rigs tend to have a stong CE aft, and thus incorporate long keels. If you want to go that route, the nine foot boom with an 8.5 foot sail and John Leather's formula could work--but you might still have a strong (braking) weather helm. I'd track down the original design and try to improve on it. Birdbeak spars are a joy to build. Have fun.