Throat Halyar / Block Question

[merrimange]

Instead of having two blocks then to a "becket" at the throat, could you simply have a block on the mast pulling to a "becket"/eyebolt on the gaff, - it seems it would allow further height say a couple or more inches compared to the two block set up per plans. That couple of inches goes quite a long ways for sail shape and mast height?

What's the catch if I do it that way? I do have the recommended "spreader" on, so sidestays are not a hinderance. Thanks in advance.

Test launch next weekend.

[Frank Hagan]

There are a lot of ways to attach the gaff to the throat or peak halyard; some of them are outlined on our page at http://www.messing-about.com/gaffrig/gaffhaly.htm (I just noticed I don't have a link to the Gaff Rig Pages on the rest of the site anymore, so people may not know they are there!)

You do need the "purchase" at the throat halyard; it, more than the peak halyard, is doing the hard work of raising the sail. Having a two part purchase, if I understand your question correctly, instead of a three part purchase would mean you are doing a lot more work to pull the gaff and the sail up the mast. I wouldn't go less than the 3-part purchase for the throat halyard.

[Dave R1]

Here's what I have for my throat halyard.

Becket block on the mast and a single block at the jaws. This is the same as illustrated in the first drawing in Frank's link. I think Frank is correct regarding the 2 or 3 part purchase. That being said, I haven't had any trouble with the arrangement I have.

[merrimange]

Frank - that link helps considerably - didn't realize it was there. Good stuff.

I don't mind a heavier "pull" raising the mast, as it is infrequent, so I'm not seeing a major reason beyond that that it wouldn't work. Though, I think in reading your response though that it puts more pressure on the eyebolt at the gaff jaws, versus where plans call for a block attached to the eyebot then back to the "becket" on the mast.

I think I understand the "purchase" vocabulary you describe and on the link.

[Frank Hagan]

Frank - that link helps considerably - didn't realize it was there. Good stuff.

I don't mind a heavier "pull" raising the mast' date=' as it is infrequent, so I'm not seeing a major reason beyond that that it wouldn't work. Though, I think in reading your response though that it puts more pressure on the eyebolt at the gaff jaws, versus where plans call for a block attached to the eyebot then back to the "becket" on the mast.

I think I understand the "purchase" vocabulary you describe and on the link.[/quote']

Raising the sail, not the mast ... and you do it every time you launch, at least, and sometimes more than once a day. But you're right, once its set, you are sailing along. Sometimes the peak halyard needs fine tuning for sail shape, but usually the throat halyard doesn't need to be adjusted once the sail is up.

"Purchase" is important, especially if you have a wooden mast and mast hoops ... you have to overcome the friction to raise the sail. To count the "parts" you count the number of vertical "ropes" you see between the blocks (actually, its "sections of the same rope between the blocks", but I hope you get my drift). In Dave R1's message you see three there. The difference between that and just having two ropes is substantial ... you are reducing the amount of resistance by 50% by going to a three part purchase. And also the amount of stress put on the through-bolt at the mast. Here are two diagrams showing 4 and 6 part purchase ... 4 or 6 "ropes" can be counted between the blocks ... from Lewmar's excellent page full of technical details you probably will never use (at http://www.lewmar.com/webcat/technical/hard_tech_ref.html):

The problem with going with the 2 part purchase like you are planning is that if it doesn't work, you need to buy a complete new halyard ... so if you plan to use expensive line for the halyard, buy enough to do the three part purchase. You can always cut it shorter, but you cannot make a good enough splice to go through blocks to make it longer! Of course, you could always have some nice double braided (and expensive) dock lines, like I have!

[Bob Taylor]

If you can get to Terry's website, sandbars and driftwood, I've posted pictures under the Vacationer link. I rigged a system to hoist the gaff that has a fiddle block attached for gaff trimming. Saved a lot of line this way

http://groups.msn.com/sandbarsanddriftwood/_homepage.msnw?pgmarket=en-us

[Dave R1]

Bob, FWIW, it doesn't look too promising for the picture's on that site. All I get anyway are red Xs.

[Bob Taylor]

I posted a diagram on this website's gallery under my name. If you need more explanation please let me know. Since there is a fiddle block (resists twisting) used for the gaff peak adjusting attached to the throat halyard attach point, the need for the four part rig is removed from the peak adjustment and this greatly reduces the amount of line needed. Hope some of that makes sense!!

[Frank Hagan]

Bob, I'll have to take a look at the pic ... the thumbnail came out OK, but the full size pic doesn't show (its something in my configuration ... I'll check it out and post when I have it fixed).

[Frank Hagan]

OK, here it is ... for some reason the "permissions" were not right on the file ...

[merrimange]

guys thanks alot. I'm test launching this weekend - been working all hours. question - what is a fiddle block?

[Barry Pyeatt]

This is a drawing in it's simplest form. Smaller sheeve below and a larger one above allows straight line with out uneven pulling power or tendency to pull off to one side or the other.