2 part or 3 part halyard

[ongolo]

Hi all,

I would like to know whether to rig a two part or a three part throat halyard for a gaff schooner.

The gaff weighs about 40kg, sail area is 37sq.meter at 400g/sq.meter amounting to about 20kg including bolt rope and cringles.

So in effect we have to lift 60kg plus the tensioning of the sails.

Now should I use a two part and run the risk of having too little length for a three part or start with three part and cut a piece off.

I would like to get it right straigthawy.

Thanks for any advice.

regards ongolo


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[Peterduck]

A tackle system is the same as a gearbox, in that you can usually put effort in one end and get more effort out of the other. However, if you try to do it the other way round, it won't work. In the case of a halyard [either throat or peak] this means that if you have too many parts to the tackle, then when you want to drop the gaff, it won't happen. I made this mistake when rigging my ketch, and when faced with a squall, couldn't drop the sails in time. I have since reduced the purchase on both the throat and peak halyards. If your gaff weighs 60kg, then most of that will be taken by the peak halyard, with a small amount being carried by the throat. I would suggest trying first with some cheap cordage a simple two part tackle for the throat; fixed at the jaws, through the block at the hounds and back to the deck. If you're happy with the purchase, use the cheap stuff as a messenger line to reeve the good halyard. Similarly, don't try to put much advantage into the peak halyard, either, or you won't be able to scandalise your sail when you need to. Remember, when hoisting, you can use all your body weight, initially, followed up by swigging the last bit. Swigging is a very powerful operation.
Peter.

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[Mirelle]

I think that there are two numbers missing - the weight of the boom in relation to the peak, and indirectly the throat, halyard, and the degree of tension put into the sail.

The weight of the boom is relevant because you want the number of parts in the throat to bear a definite relation to the number of parts in the peak, for convenience of hauling. It is usual to seek to get the luff of a gaff sail as taut as you possibly can.

Unfortunately I think in square feet, not square metres. 37 square metres is about 400 square feet.

The mainsail on my cutter is 450 square feet, very heavy oil and ochre dressed cotton/terylene canvas, and we have the usual four part peak and three part throat halyards, without purchases. This arrangement works well and I have never had any problem with the sail coming down under its own weight. The blocks are the original pre-War wooden ones, 5" long with "patent" (roller bearing) sheaves 2 3/4" x 3/4" and 14mm rope. The throat halyard when I bought her had two parts and a purchase; I found this awkward and prefer the three part arrangement.

One factor to consider is the need to re-tension the luff after reefing, with the sail full of wind.

I hope this helps!

<hr width=100% size=1>Que scais-je?

 

[ongolo]

Mirelle and Peter,

Thank you very much for your advice and the tips, you have confirmed amongst other things, that I always tend to to "over ingeneer" things.

So I have to take the wife off her stupid diet too, that she can hoist sails too.

Where do you people get your blocks? I had to make my own.

regards and thank you very much

ongolo




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[Peterduck]

I made most of mine, too. I didn't find it difficult, and I'm very pleased with the result. Unfortunately, I couldn't organise the roller bearing sheaves which Mirelle's blocks have.
Peter.

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[Mirelle]

Roller bearing sheaves are as scarce as hen's teeth! I did manage to pick some up secondhand, years ago, and I have made some blocks using them, but most of the blocks came with the boat - they have all had new pins, some have had new straps, some have had new cheeks, so the rig is a bit of a "roadsweeper's broom" really!

<hr width=100% size=1>Que scais-je?

 

[ongolo]

I am using delrin sheaves at the moment, but one day when I am RICH and idle, I will make on my little lathe bronze shaeves with bronze rollers. There is an australian doing this for friends.

Not difficult, just time.

I have two types of blocks, a rounded type made of rose wood with stainless straps and an industrial type (I like the shape better) with galv. straps and made from ash.

thanks and regards

ongolo


<hr width=100% size=1>1000 dream about it, 100 talk about it, 10 start and 1 completes it

 

[petercrook]

Colin Frake, Stnadard Quay, Faversham, Kent ME13 7BS 01795 531493 makes blocks (and other useful things) in various materials and styles with "oilite" bushes. He will also sell you the sheaves and bushes separately. I haven't bought any yet but they look attractive in his brochure.

And of course there's Classic Marine.

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