Self tacking staysail question.

NUTMEG

NUTMEG

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I have posted this on the East Coast forum but thought it might be better here. Sorry.

I read the latest ECS article about a Bawley kept on the River Blackwater. She has a self tacking jib, running on a metal horse across the foredeck.

Now, this set me thinking.

I have a Mk1 Cornish Crabber, flush decked, no headroom, wife hates it.

Can anyone explain how self tacking works? Would it be reasonable to convert to self tacking on my Crabber? What would be involved, apart from making the metal horse to take the tack.

All thoughts most welcome. Not getting the drill out just yet, just musing.

Cheers all

Steve
 
For a start, the staysail needs to not overlap the mast at all. Don't know if it does on a Crabber.

You also need to figure out a way for the sheet to stay the same length when the sail goes from one tack to the other, and for the sheet not to pull the sail in towards the centreline. This usually means either running it forward across the foredeck to a turning block at the stemhead, or running it up the mast to a block about two thirds of the way up to the staysail halyard, then back down and aft.

An alternative to a horse or track is a boom and a sheet to the centreline much like on a mainsail. This doesn't work so well with a roller staysail unless you also have a clew outhaul led back to the cockpit, which is OK on big boats but a bit fiddly for a Crabber. Maybe the sheet could be used as a combination outhaul and sheet, with a tackle on the outhaul part so it takes up preferentially, but I don't think I've ever seen it done.

Is tacking the staysail really that much bother? I didn't have any trouble on Kindred Spirit, a Cornish Yawl which I would think has the same size headsails. She had two pairs of cam cleats, like a dinghy, and I would just reach over and pull in the staysail then the jib with one heave each.

Pete
 
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We had a self tacking jib on our second boat - a British Hunter. It is pretty simple provided you have the necessary blocks available on the mast.

The jib needs to be sufficiently small to fit into the triangle between the forestay and the mast with enough clearance at the mast end for the blocks to get past. You fit a track - just a glorified curtain rail really - across the foredeck just forward of the mast and a runner sliding on that track carries the jib sheet and allows it to slide across when you tack. That track will typically be curved in order to keep the sheet reasonably tensioned as the runner goes across.

The jib sheet goes to a block somewhere on the mast, then down to another block on the runner and from there up to the clew of the jib. On our Hunter, there was another block with a becket attached to the clew and the sheet was routed from the becket down to the block on the runner, back up to the block on the clew and back to the block on the runner before leading up to the mast and on back to a winch on the coachroof at the cockpit. This gave a three power pull on the jib and reduced the winching effort.

In use, the runner on the track is always at one end or the other and you control the jib angle by shortening or lengthening the jib sheet. It worked well provided we kept the track very clean and lubricated the runner with a suitable silicone spray. If not, it did have a tendency to not come across fully when tacking in light winds. It will always be underpowered relative to a standard genoa since it needs to be less than 100% in order to be able to slide freely.

I think you should be able to purchase all the necessary components from someone like Barton or Lewmar. It's not particularly complicated and a decent amateur engineer should be able to make it from scratch but you do need a decent combination of physical strength and good bearings if you are going to produce something that operates satisfactorily.
 
I would just add a caution to be aware that with a S/T fore-sail you can't control the sail shape as well as you can with a conventionally sheeted one. S/T jibs are fine on the wind but as you come off the wind and slacken the sheet the lack of downward pull on the clew allows the sail to twist excessively so that the upper leach sags away to leeward. This can only be cured by over-sheeting the sail. Some people rig barber haulers to improve the sheeting angle but by the time you've done that you could have sheeted in a conventional jib. I'm speaking of boomless sails of course. Many people are happy to live with the limitations of S/T fore-sails because of the ease of handling.

My Channel 31 came with the standard Hunter S/T jib as described by Maby. This season I had a conventionally-sheeted one made by Goachers at Windermere: it only has a small overlap (about110%) but it pulls noticeably better than the S/T. It's difficult when single-handed though as the Hunter has the winches at the back of the coachroof rather than on the coamings and I can't reach them from the tiller.
 
Absolutely agree with Jim - it's very hard to come up with a self-tacker that performs well. On the other hand they are very convenient when you are short handed. We had both a self-tacking jib for our Hunter and a conventional genoa. For short passages when we could both be on watch the whole time, we would fly the large genoa. For longer passages when one of us would be sleeping some of the time, we would fly the self-tacker since it was more gentle on the helmsman.
 
It's possible to have a self tacking jib that overcome most of the problems described..

The sailmaker can make a sail with a standing batten - a way to increase the sail area and improve the slot between main and jib (it can still sit on a furler)
I have permanently rigged "barber haulers" that I can adjust from the cockpit - used to;
1) Close the slot when sailing upwind
2) Use to haul the clew out and down when sailing with the wind on the beam or further aft

With the self tailing jib I get better AWA going upwind, because of the smaller sheeting angle - don't miss the genoa.
 
I'm not very familiar with Crabbers: you say this is a question about a self-tacking staysail, so is it fair to assume that you have a staysail and a jib? If so, the staysail is probably fairly small and there won't be an issue with it passing around the mast. Lots of old boats with jib and staysail have the staysail self tacking, quite a few that I have seen with very basic arrangements: typically a horse in front of the mast and some way of sheeting the sail to a shackle that is free to run from one side of the horse to the other as the boat tacks. As others have said, hard to get a really good set to the sail, but then it's not doing as much work as the conventionally sheeted jib anyway. You can improve that by having various sorts of boom arrangements. You'll find that John Leather's Gaff Rigged Handbook covers all this stuff in detail, with various sheeting and booming arrangements covered. If you trawl around sites like Historic Ships Register or some of the smack sites you will find some pictures, eg try http://colnesmack.co.uk/ where you will also find links to sites like smackdock that have loads of info on them.

I have a basic "sheeted to a horse" arrangement on my boat, and it works fine.
 
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Sophie19 said:
Thanks all, I will follow those links up chal, thank you. Just a silly notion but an appealing one for some reason. Maybe I need to get out more!
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Not so silly - I'm think of having the self-tacking gear fitted to ours next spring.
 
I have dabbled with the idea of a self tacking jib on my 21fter for racing. We tend to get lots of wind in summer so a smaller jib would be OK provided I could still fit a big genoa in light conditions. I concluded that a jib ona boom would give best down wind performance as well as windward performance. (given the reduced sail area.)
I was mostly put off by the fact that the bow rail would limit the outward swing of a boom where the gooseneck was right at the bow. Also the boom would be quite lethal with anyone on the foredeck. Finally gave up on the idea. However a jib on a boom should give good control of sail shape. I could not get a vang in under the boom with no space but concluded that a supplemetary sheet from the gunwhale on each side should provide the down pull on the boom and also if wanted of the wind a bette rpull down with boom right out. The boom would have a central sheet doing most of the work and the supplementary sheets just tweaking the sail once a tack was completed.
Just a few thoughts on one approach to self tacking jib. I don't think there is enough control of ST jib on a travelelr or horse. It would be just like a main without a boom. It can be done but not well. good luck olewill
 
Sophie19 said:
What would be involved, apart from making the metal horse to take the tack.
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Depending on what options you have to mount the horse / track, you may find that your existing sail isn't suitable. The lead for the track is likely to be further forward and / or lower than the current sheet lead (guessing, as I don't know the arrangement on the Crabber) so the clew of the sail needs to be cut with this in mind.

We have a Hunter Channel 323 with a self tacking jib which a previous owner had converted to conventional deck leads and it would never set properly because the sail shape didn't match the new leads. I re-fitted the self tacking gear (I had intended to, anyway) and the sail sets well on it on anything tighter than about a beam reach. I quite like it.

If you can duplicate the angle of your existing leads, that might be the best option.
 
Dehler 41Ds

Albeit a much bigger boat than the Crabber, Fuga has a self-tacking jib in a high aspect 7/8 rig, and it works very well indeed. We have a curved track with sheet running through a sheave well up the mast. There is a second track and sheet for use when reefed, but we find this a waste of space.

Makes her very easy to sail in small spaces to windward. We have rigged 'control lines' so that we can back the jib to heave to, or if required for manoeverability.
 
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