To better let you see what is being discussed; here are the sketches I have made for a JR for Pol's boat. As you can see, I have stretched the lead a bit here. In case the boat ends up with more lee helm than can be fixed by shifting the sail aft, I suggest fitting a little mizzen. Such a triangular mizzen with a sprit boom is super-easy to set and furl (on the mast). Cut perfectly flat, the mizzen can do second duty as an anchor riding sail. See text below the photos.

Arne

(See Arne's sketches, section 2, photos 4-10)

POL BERGIUS wrote:

Thanks very much for your suggestions David. I'm afraid that the schooner rig gets the thumbs down, though I like the look of it and it would be v handy! But I am well over 6' and this is the part of the boat i can almost stand up in so the reduction in headroom with what reinforcement that the cabin top would require would be a limitation. A more annoying specification is that our JR on Annie should be convertable back to gaff with relative ease. She is the first of her type and they are quite popular boats as they are. 

I take your warnings about sail area seriously. After sailing on a 25' ish dipping lugger recently and been very impressed with her close-windedness and power in a light breeze, I wonder sometimes if 56sqm is a bit over the top for Annie as I expect the the big single sail could be quite a bit more powerful than the relatively "modest" gaff rig of the same overall area (with tiny tops'l)? What does anyone think of that?

I'm thinking of this now as I have a sketch scaled up from Arne's Johanna template at A/R 2.0. Somewhere around this A/R (unless I've made a boo boo which is perfectly possible as all this stuff is done well after lights out time!)  I THINK I can get a 56sqm sail with a mast position about 1.22m from the stem, which would plant it straight through the (disposable/replaceable) sea loo. At the moment my sketch's CE is just a few cm forward of the gaff rig's CE so I believe with tweaking I must be able to get it pretty close. Unless I'm mistaken of course. I will post this sketch as soon as I can get it closer CE-wise and tidied up a bit.

It is great good fortune that I have a mass of lead pigs right in my proposed mast step area which will be easily removed. This will go some way to redress the balance of having quite a heavy timber mast up there. Her working boat bow, though not as full as some, should help to carry the pitching of the tall mast?

Thanks again, Pol.

I think you're on the wrong track here, Pol. A single sail with its mast that far forward must inevitably be of very low AR, and this is just what you don't want. The battens will be well in excess of 6m, which I would put as the maximum convenient length on a boat of this size. The mast will be too heavy and too far forward, notwithstanding the trimming ballast that can be removed.

To talk of bearing in mind reconverting to gaff rig smacks of a half-hearted approach which is unlikely to be successful. A good JR conversion does not affect resale value, it enhances it. To make a successful conversion, you have only to consider your own needs, now and in the immediate future.

To put it very bluntly: I think you have two viable choices:

1. A schooner rig, pretty much as I drew it, though the sail shape might be a little different, according to taste.
2. A single sail split rig with a forward raked mast going through the saloon table.

PS If you really need to go just halfway with a conversion, with the minimum amount of work, have you considered the so-called 'junkette' rig (bad name)? It consists of changing the gaff mainsail for a sail with the battens and sheeting of a junk sail, but with jaws that engage the mast as for gaff rig, and keeping the existing headsails. It's half as good as a true junk rig, but half the commitment of resources. It gets you the junk's ease of reefing, but little else.

Michael Moore wrote: This is very interesting to me as I want to convert my 28ft Twister 'Shandie' to JR. Pol and I have exchanged idea over the past year about converting and I have sailed my JRCorribee for around 90 hours and am now covinced that this is the way to go.

Arne kindly made a drawing of one of his sails on a Twister, but I'd like to be more conservative in sail area than 48.7m square! The Twister sails very well on its 32.55m even though it may look undercanvassed being 4.44 ton. I also want to keep the mast as far from the bow as is possible. I shall keep a keen eye on 'A new rig for Annie'

Mike

Two suggestion Michael:

1: Open a new topic, called "A new rig for Shandie". Your boat deserves a new thread.

2: Decide alternative mast positions and present them here with the distance from the bow to the centre of mast position(s). The mast position have a big influence on what sail suits the boat best.

Arne

The first, very rough drawings I've made of rig proposals for Pol Bergius' Cornish Crabber 30 Annie can now be found here, in DXF and PDF formats.

I find that I can just squeeze on a 2:1 schooner rig, with sails to the same proportions as Weaverbird’s and masts raked at 2 degrees (though it’s tight at the bow because of the plumb stem, and the foremast might have to be at 3 degrees). I think this looks quite good, as a sensible cruising rig. The main battens are 4.42m, and the fore battens are 3.12m, making for a very easily handled rig, though it might not be the fastest. The main mast is 12.7m and the foremast is 9m.