Solo Tuning Guide

What the experts say:

• P&B (2023 National Champions): tuning guide
• North Sails: tuning guide
• HD Sails/Jim Hunt: tuning guide 
• Rooster/Steve Cockerill: tuning guide
• Hyde Sails/Ben McGrane: tuning guide

The Solo Scribbles Guide

Mast Foot Position

The middle position (on a modern Solo).

Details: there are usually three places the mast foot can go and most guides suggest putting it as far forward as possible. In my view, this creates a rig that leans back too far, giving you a lot of weather helm and a low boom that is difficult to get under.

So I use the position that is one place further back than the forward one. I judge if this is correct by putting up the mast and sail and adjusting the forestay until the mast touches the back of the mast gate. In this position, the mast is leaning back a little and the boom is roughly horizontal above the rest of the boat.

Rig Tension

"Finger-tight".

Details: if you have to go red in the face trying to put in the pin, the shrouds/forestay are too tight. If the mast and shrouds are flopping around a lot, it is too loose. Some expert guides suggest a very loose rig. I think this is so you can bend the mast even more than usual. I haven't found this to be necessary so far.

Mast Chocks

Depends on your sail.

North sails: a 10mm chock in front of the mast. Edge sails: a 2mm chock or none at all. P&B, Hyde and HD sails are often similar to North, but it can vary.

Details: as the Solo rig has no spreaders, the only way to control the mast bend is forestay tension and mast chocks. As you pull on the kicker, you can see the mast moves forwards in the mast gate. This means the lower half of the mast is bending. If you need to limit the amount of mast bend, you can put a chock in front of the mast to shorten the distance the mast can move forward in the gate.

All sails have some luff curve as part of the design. If you spread out your sail on the ground, you can see the curve more clearly. Sails designed for a lot of mast bend have more curve. Sails designed for less mast bend have a straighter luff.

To go quickly upwind, the curve of the mast should (approximately) match the curve of the luff of the sail. If the mast bends more, the wing shape of the sail collapses which stalls the airflow, reduces lift and you go very slowly. If the mast bends less, the luff area of the sail is not flat enough and the boat will not point very high.

Mast Chocks - Very Light Winds

Put the chock behind the mast.

Details: as the North Tuning Guide recommends, you can put chocks behind the mast in very light winds. The reason to do this is so that you can bend the mast to the right shape upwind without having to put on the kicker. Putting on the kicker in light winds can result in too much tension on the leach of the sail which stalls the wind flow and therefore is very slow. The slight complication here is that if you need to bend the mast a lot you need a bigger chock behind the mast in light winds, but in other winds for the same setup you would have a small (or no) chock in front of the mast.

Final Thoughts

Each sail and mast combination will be slightly different. The important takeaway for upwind performance is to match the curve of the sail to the bend of the mast, with a reasonable amount of kicker on.

You might wonder why no one talks much about downwind performance. Obviously it is very important. I think the reason is that changing the position of the mast and rig tension has little effect downwind. I have noticed that the sails with more luff curve perform better downwind. I think that is because the Solo sail is wide and short compared to others and keeping the maximum depth of the sail further forward makes it a little faster and easier to handle. That's just my theory though.

Ian Cherrill