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mdevour
04-30-2003, 10:08 AM
It looks like it won't be long before we'll be setting up the rig for our Weekend Skiff (http://www.eskimo.com/~mdevour/boatproject.html) .

This gaff sloop rig is more than the designers intended for the hull so I'm making it up as I go, taking inspiration from books, web resources, and other boat designs.

The Herreshoff 12 1/2 and its variants are of similar size and complexity. One thing I have not been able to find is a detailed photograph of the masthead arrangement of that, or any other small gaffer.

The halyard cleats are on the bulkhead next to the base of the mast, which suggests to me that the halyards are very likely to contact the gaff jaws some of the time. Is this true?

Right now I plan to build a small pinrail attached to brackets on the base of the mast. I can arrange things to minimize interference and hang-ups, but it'll be hard to avoid having the gaff rest on one or both of its halyards whenever it falls off to that side.

Is a certain amount of contact between gaff jaws and halyards acceptable in a 16 foot dinghy with a 75 sq ft mainsail?

Mike

[ 05-04-2003, 10:48 AM: Message edited by: M. G. Devour ]

frameshop
04-30-2003, 11:18 AM
Mike. I have a Haven 12 1/2 ( www.havenbuilders.com (http://www.havenbuilders.com) )look under builders, roger mullette. I did have a problem with the halyards catchhing up under the gaff jawsI eliminated the problem by making sure they run outside of the jaws. all the halyard cleats are on the bottom of the mast, not on the bulkhead. This makes it easy for all lines to be tied off when I take the mast down for trailering. I would be happy to fax you a rough sketch of the masthead fittings as I have them. Roger :)

mdevour
04-30-2003, 03:41 PM
Hi Roger,

She's a pretty one!

I had the same idea about having the cleats attached to the mast. Everything in one unit.

Most of the books on gaffers talk about keeping the halyards away from the hoops and jaws, but they're always talking about larger craft with bigger loads, and about ocean cruising where chafing is a more serious issue. For a small day-sailor knockabout, is it just not as much of a concern?

Is it enough to make sure the gaff jaws are smooth and gently curved so they don't have any way to grab the halyards?

Once again my lack of experience leaves me not knowing the answer to these basic questions.

I'm already planning to try the 12 1/2's masthead arrangement in general, with the stays, peak and headsail halyard blocks together at the top and only the throat halyard below. It'll give me the most space 'tween the halyards and jaws.

I'm also thinking of trying a parrel wire instead of line to give the jib halyard less chance of getting pinched.

Can you snail-mail me your sketch? I've got no good way to receive faxes. Or maybe I can entice you to post a photo or two, here? ;)

Thanks,

Mike

Mr.O
04-30-2003, 11:55 PM
Ditto Roger on the photos;if you've got em. Thanks Jack

mdevour
05-04-2003, 10:47 AM
I still need some input on this question. I've roughed out my gaff jaws, but my mistakes are catching up with me...

The plans called for the mast to be tapered, which I did. That was before I learned that it would have been better for a gaff rig to leave it more or less constant section up to the jaws, and taper it less overall.

To compensate, I've cut the inside of the jaws to the diameter at the base of the mast, and hollowed out a smaller radius at the angle the gaff will set to help it align itself when peaked.

The upshot is the gaff jaws are a large obstacle to getting the halyards down to the deck, that is IF I'm going through with my idea of a pin rail attached to the base of the mast.

I like the idea because it lets the halyards go on and off with the mast; you're facing the mast and sail when hauling; and it gives us a nice place to coil down and hang the falls so we're not sitting on them.

So I reiterate my question from above and add another:

Is it okay on a small boat like this if the gaff or jaws end up knocking into the halyards at least some of the time, as long as I provide a way to keep them from getting trapped by the jaws, e.g., using a rigid parrel wire?

Would it be reasonable to attach a couple of ... I don't know what to call 'em... cranes? ... with bullseye fairleads at the end so as to change the lead of the halyards slightly to get them out 3 or 4 inches, beyond at least gross interference with the jaws?

The gaff halyards would need one such 'crane' with two fairleads on the starboard rear quarter of the mast, and the headsail halyard one on the port forward quarter, all just above the jaws when hoisted. I can probably make them up out of bronze plate and arrange the strain so it's mostly compressive -- though it's not going to be too severe in any case.

Thoughts?

Mike

Paul Scheuer
05-04-2003, 12:09 PM
Cross trees might be in order. Might be able to incorporate spreaders, not that you need them.

For inspiration:

http://www.imagestation.com/picture/sraid61/p4507989e8d6f9f3320884e079b5a9e27/fc378ff5.jpg

http://www.imagestation.com/picture/sraid61/p01960a5f6a1d48546144ec06105f8590/fc378ff3.jpg

If you find that the tapered mast is too much of a problem, you might want to consider a new mast and use the top section as a topmast.

mdevour
05-05-2003, 07:54 AM
Originally posted by Paul Scheuer:
Cross trees might be in order. Might be able to incorporate spreaders, not that you need them.
No, I probably don't need spreaders. ;) Just something to hold the halyards a few inches from the mast. Whatever it is would have to be secured well enough to handle a little torque, since the gaff halyards would be pulling it backward on one side and the headsail halyard forward on the other.

Those pics are from, what, about a 40 footer? :D



If you find that the tapered mast is too much of a problem, you might want to consider a new mast and use the top section as a topmast.Well, I certainly can replace the mast if I can't make things work out. Could probably make it a foot or two taller, as well.

A topmast, eh? The boat'd start to look like one of those miniature schooners I've seen designs for. tongue.gif

Could carve a new, longer gaff out of it, though. A higher peak is one thing that the rig could probably tolerate, especially with a longer mast. Would look nice, too.

For now, though, I take it that a fairlead or two, however I choose to mount them, is not ... err... out of line with good practice?

Mike

Paul Scheuer
05-05-2003, 06:43 PM
The drawings are photos of the pages of a reprinted version of Wooden Ship-Building, Charles Desmond, originally published c1919. The drawings for the mast, boom and gaff are for a five-masted schooner, 2,500 tons. A little larger than your current project, perhaps.

The plan view (from above) in lower part of the second image shows fairleads projecting from the forward (left)edge of the forward crosstree.

mdevour
05-05-2003, 08:35 PM
Originally posted by Paul Scheuer:
The drawings for the mast, boom and gaff are for a five-masted schooner, 2,500 tons. A little larger than your current project, perhaps. Umm, yes. A bit bigger! smile.gif Thank you for the reference.


The ... lower part of the second image shows fairleads projecting from the forward ... edge of the forward crosstree.I see that now. I will pull something together to keep the leads out of the jaws. It may not be as elaborate as a crosstree, but will fulfill the purpose.

Thank you, Paul.

Mike