I think Arne’s three reasons for sticking with the un-split Johanna-style rig are valid. The SJR seems to require more work in the building, it has not yet been proved that SJR is better to windward, and the Johanna rig seems to pack a little more sail area and luff length per metre of mast height. Robert’s comments about high AR/ low AR are also worthy of thought. Another thing, at first looks, the lofty style of the high-peaked Johanna rig just looks so much more lovely than the rather brutally simple shape of the Amiina rig (though, when something works well we usually soon learn to like the looks of it.)
- 1. It’s a funny thing (and a good thing too) that once we make a choice, we all have a tendency to want to stick with it, and see only its advantages, and I think my next sail will be another SJR – after considerable thought. I want to do it better next time. I know it will take a bit more work and accuracy, and shelf foot requires a bit more seaming than the barrel/rounding method of getting camber – but I just love the geometry of it. I will say one thing in favour of the Amiina rig, in the matter of sail-making. There are less panels, very little lofting and a lot of replication – in that respect it is simple to make.
- 2. I will say this much about performance – if the SJR is superior to windward (and I say “if” though I think it ought to be) – it will only be so if the sail is well-made and the person on the helm is skilled at getting its full potential. I have proved that a SJR sail not particularly well-made, and in the hands of a helmsman with a fairly short concentration span, will perform averagely well to windward but not outstanding. I think I can say the sweet spot when going to windward is narrow and the sail might prove to be less forgiving of sloppy helmsmanship than an unsplit sail. I suspect Arne would get the best out of SJR just as he does with his Johanna.
Arne says that any junk rig will go well down wind. I don’t know – all I can say is my SJR is a delight and a joy when reaching and running, and feels very powerful.
- 3. As for mast height – I am not quite so sure about that, I have still not been able to find a good explanation of minimum mast requirements, and in any case we are not talking about a great difference. And the fact is, you can over-canvas a bit and be prepared to reef a little early on any of the junk variants. Slieve says that with SJR you don’t need to and prefers to maintain the slightly better performance (higher AR) of an unreefed sail – maybe so for racing, but for inshore cruising: I think I am a bit over-canvassed but the boat sails quite well reefed and I have rather come back to Arne’s idea of “cram on a bit more sail, you can always reef.”
I am still mulling over the best rig for my little scow project (the Pelorus is now just my home and the proposed conversion has stalled, I am embarrassed to say.) I would be interested in (but will probably ignore!) an expert opinion on the following:. My SJR for Serendipity was a prototype for the scow and I think I will continue down that road. But the idea of a low AR “Arne sail” is still lurking in my mind. Here are the criteria: Its not a race boat, its an old man's retirement home. What a scow needs is POWER and it is no use seeking close-winded performance with this sort of vessel. In the old days you would say it needs a gaff rig, and a Bermudan rig would be no good. With a scow like this, sail area is more important than high aspect ratio. When going to windward you have to lay off a little and opt for a bit more speed, rather than pointing high. So with that in mind, which rig looks best to the experts? (The SJR looks better to me, now, because I have got used to it, learned a little bit about it and convinced myself. Oddly enough, ideal mast position favours the low AR Arne sail.).
What say you?
PS I can't help adding that the soft wing appeals to me as the absolute ultimate in junk rig development and potential and I would dearly love to go down that road. But I am daunted by my lack of the technical skills that are required in making the hardware.