Some pictures thanks to Anne Brown:
Sail Flogging and thickness
The sailcloth is fairly light – 65gsm. Overall I’m happy this is fine; however the rear edge of the jiblets is not under tension so can flog in gusts. I’ll monitor and see if it needs to be thicker. I’d only need a new jiblet panel which wouldn’t take long to make. The big advantage of the thin cloth is it takes a good shape in the slightest breaze.
Throat Hauling Parrel
The yard angle is adjusted by a Throad Hauling Parrel (THP). The Yard Hauling Parrel doesn’t do much, although it probably helps keep the yard under control near the mast.
However as shown in the picture above there is a problem with the yellow jiblet as this takes the load of the THP. I suspect this makes no difference whatsoever to the performance of the boat but it doesn’t look elegant.
The Split Junk Rig (SJR) solved this by using the shape of the luff and leach to balance the forces in the sail, although some load in the THP might still be required to compensate for changes in the loads on the sail (e.g. with changing sheet loads).
The classic Practical Junk Rig (PJR) book has a small luff gap between yard and top two battens which I suspect helps to lock the spars together with minimal scope for the spars moving around and distorting the sail.
Custard’s sail was a bit of a compromise due to construction mistakes (started building from the wrong layer in QCAD – oops) and hasty adjustments to compensate for this. Thus the gap at the luff between the yard and top two battens is bigger than intended which leads to more movement than desired.
I’m sure there is a neat way to take the load out of the jiblet panel – when I get time I’ll see if I can find it.
The sail doesn’t currently have any downhauls. Overall this doesn’t seem to matter much – the bottom batten lifts a bit in stronger winds which curves the luff of the bottom panels. The other panels are still held in tension.
The SJR downhaul system would help with this. However I don’t have any spare turning blocks and I’ve got enough string in the boat anyway. I’ll probably rig a bungy downhaul with a hook at the top to fit over the lowest batten and use it if I feel like it. It would require crew involvement to set it or move it before and after reefing and they might be busy doing more important things.