Throat Halliard

[brokethebox]

I work on a sail training boat which is gaff rigged and i have wee problem you guys may have an ingenious solution to!

Our throat halliard has a four foot length of chain from the mast band at which it is attached to the upper throat block. There has been a little damage caused by that upper throat block then tapping lightly on the mast over time and breaking the varnish layers there, allowing water in. The damage i have fixed (no big job as really had only cracked the varnish and caused about 1/2mm of dampness).

I guess my first question is why the length of chain and not run the upper block directly from the crane on the mast band. (Other than that i would need an extra 24' of halliard).

And secondly, any hints on stopping the damage from reoccuring? Had thoughts on a lower band to get rid of the need for the chain but this seems costly, or of having a larger crane welded to the existing mast band to hold the offending block further from the mast.

Any help would be much appreciated!

James

 

[cliffordpope]

This problem sounds somewhat connected to one I have puzzled over at times - how to stop the throat downhaul rubbing on the gaff jaws.
Where does the downhaul run? Does it pull in towards the mast, thus tending to swing the upper block against the mast too? If so, then it sounds as if repositioning the block directly on the crane/band might stop this.
Alternatively you could consider re-routing the downhaul, eg by running it well away from the mast, say towards the foot of the shrouds.
How close does the lower block approach the upper when the gaff is raised? Would extending the length of chain to the maximum amount ensure that the blocks were held more tightly - chock-a-block in fact?

 

[mclark]

I imagine the chain may have been put there as a convenience sometime in the past, maybe the halliard chafed and this was a way of shortening the run of halliard?

First thought on the arrangement - get rid of the chain - weight in the wrong place for a start and no need for it.

Shackle the upper block direct to the crane and hopefully splice an extension on the tail/fall of the halliard (it wont have to pass through a block) if you are really smart with your ropework of course you could use a long splice which wouldnt increase the diameter of the rope so it would happily pass through the blocks.

If you are determined to stick with the present arrangement then why not leather the block so it doesnt damage the mast. Heavy leather tacked to the block with copper tacks then well soaked in neats foot oil and finally coated in some tallow would be a fine and seamanlike solution. If you find it difficult to get the leather to sit neatly on the shell of the block I believe soaking the leather in water for a good while first will make it more flexible.

 

[brokethebox]

Many thanks guys!

Long splicing skills are there, just unused in a little while but nothing that can't be rectified by opening Toss's bible!

As to a downhaul on the throat, thats not something i have or use, you can drive the gaff down by keeping the peak high as you lower the throat. The larger and heavier the gaff, the more you have to do that, i've found.

And its funny, i'd very briefly considered leathering the mast before i threw that idea out but never the block!

 

[Peterduck]

It sounds to me as though the point where the halyard is attached to the gaff is too close to the mast. Can you reposition it a little further along the gaff away from the mast?
Peter.

 

[cliffordpope]

[ QUOTE ]


As to a downhaul on the throat, thats not something i have or use, you can drive the gaff down by keeping the peak high as you lower the throat. The larger and heavier the gaff, the more you have to do that, i've found.



[/ QUOTE ]

Sorry, my sloppy ignorant terminology. I meant the bit of halliard you pull on to raise the gaff. It's angle of pull will determine the position the upper block wants to adopt.

 

[mclark]

I use leather a lot on White Heather - its extremely functional for anti chafe purposes and looks great too. I find if you coat it with neats foot oil or mars oil a couple of times a year - making sure the oil really penatrates, it will last a very long time. The tallow is just there as a lubricant.

Ideally the throat fitting should comprise a flat strip of steel along the line of the gaff and passing through the wood of the gaff and pinned athwart through the centreline (very difficult to describe). This fitting should be capable of swiveling to take up the changing angle of the gaff as you peak it up. The idea is that the throat halyard is shackled to the top of it and the throat of the sail at the bottom. As the angle of the gaff changes (as you peak it up) the load of the throat is always in line with the halyard. If as I originally had youu simply have an eyebolt in the top of the gaff to shackle the halyard to, as the gaff is peaked up the block will be forced into the mast.

 

[cliffordpope]

That's what I have, except that the metal plate is incorporated into the pivotting wooden tumbler (is that the word?) that bears against the mast. Basically the lower block attaches to one end and the corner of the sail to the other. The gaff just pivots about the middle on a pin passing right through the inner end of the gaff jaws.
The upper and lower blocks are attached so that the sheeves open sideways, so the tail part of the halliard pulls slightly sideways, not against the mast.

 

[Seagreen]

For what its worth, re-attaching the upper block to the crane, and losing the chain would surely position the upper block slightly away from the mast, so chafe and knocking would be avoided? 4 foot of chain sound a lot for a bad lead.

Only three reasons for the chain:
1) A way of making use of a shorter halyard than necessary. So get a longer halyard- short term cheap fix before boat was sold in the past IMHO.
2) Bad lead of the fall of the halyard at the crane - don't think this is the real reason as this'd be fixed when the rig was first set up. Rectify by changing the belaying point of the fall, possibly?
3) the Crane doesn't stand out from the mast enough and the chain adds flexibility to align the two blocks vertically. Still, 4' is a lot of extra play, so I don't think its that.

First, try the upper block back on the crane and see what gives.
If the lead of the fall is poor, you can add leather or plastic pipe sections to offending parts, including the backstays if the fall belays to a pinrail by the shrouds. The boat sounds too big for this to be the case and I think you belay the fall to a pin at the foot of the mast. In which case, the chain may have been added to stop the fall from chafing the sides of the gaff. If this is so, add brass keelband (or hardwood strips) to the side of the gaff jaws taking the rub.

My hunch, see reason 1. It was a cheap and dirty fix for a short halyard that gets enshrined as gospel with the new owners. Getting a longer halyard, putting the upper block back on the crane and start from there seems best.

Be nice to see a close up of the situation if you can post one up.

 

[brokethebox]

Everything is stripped down at the moment and i'm just about to begin putting her back together (all blocks and spars have been varnished and serviced if they needed it) so a photo can follow as soon as that is done.

There have been a goodly number of skippers before me so you could be right that it was a temporary fix though to be honest the size and quality of chain wouldn't have seemed to have saved them much!

I'm rotating halliards anyway and replacing the peak with new so that'll go on the throat and be long enough i'm sure to try it directly from the band i'm sure.

And to Manx Nobby, we run out of Liverpool and are in Peel quite regularly through the season so may see you there!

James

 

[mclark]

Good luck with re-arranging things - and when you are next at Peel please say hello