Catamaran technique - part 1

Cat legend Mitch Booth kicks off thedailysail's new series with his views about techniques for sailing upwind

Mitch Booth is Mr Cat. Arguably the most influential name in modern cat racing, he is reigning Hobie Tiger World Champion, and has numerous Tornado credits to his name, not least a Bronze and Silver Medal at the Olympics. And he was responsible for changing the Tornado from a two-sail single-trapeze boat to the Tornado Sport of today, capable of 15 or 16 knots of boat speed upwind. He is currently campaigning a Tornado with Herbert Dercksen, in a bid Gold to his collection at next year’s Games in Athens. Here he kicks off a new 10-part series on high-performance cat sailing with a look at how to get the most out of your cat upwind.

Upwind sailing – rig set-up

With the speeds that modern twin-trapeze cats achieve, upwind sailing is all about minimising drag in the hull and rig. The first priority is to get the windward hull out of the water, but once you’ve done that you can think about knocking the power out of the sails and flattening them off as much as possible whilst keeping that hull flying.

Cunningham
We pull as much Cunningham as we can whilst keeping ourselves on the trapeze. In a big breeze we pull on as much Cunningham as we physically can. You can really bust it on in those conditions.

Mast rotation
Mast rotation is a more subtle control. Rotate the mast too much and the mast tip is bending in the minor axis, and the top of the sail twists off too much. But induce too little rotation and the top of the sail is too full compared with the rest of it. A lot of it comes down to feel and experience. I look at the shape of the sail and gauge the depth and twist to determine the amount of rotation required. But for some general rules of thumb, the mast rotation arm should be pointing at the leeward shroud on the F18, and on a Tornado it should be pointing from anywhere between the shroud to the back of the centreboard case.

The traveller, on the other hand, is really simple. On our boat it stays on the centreline at all times. It should be bolted there really. We use it only for starting and possibly as a bail-out in case of a capsize. I never hold it. If you’ve overcooked the layline and don’t want to ease mainsheet, it can be useful to let the traveller down sometimes, but that’s about it.

Jib position
In light airs we have the jib track closer in board, and the clew board higher, and not sheeting on quite as hard as usual. As the breeze builds we progressively lower the clew board position, and move the jib track further outboard, and we pull the sheet harder to flatten out the foot of the sail.

Shrouds
The general rule is that you want to have sufficient rig tension so that the leeward shrouds never quite go loose. But it’s worth noting that we have no adjustment on our rig. Others have adjustable stays but we have fixed shrouds and forestay. The physics of a rotating rig are very complex, so the more you leave it alone the better. For power control, you don’t want to use rake, but instead let the diamonds control mast bend. You want to keep the mast vertical in the boat.

Crew weight
In the Hobie Tiger the crew sits forward of the cross beam in non-trapezing conditions. As soon as the crew is on the wire, he comes behind the cross beam. As the breeze builds he comes progressively further aft until he is trapezing behind the shroud.


Upwind sailing – style and philosophy

You are looking to achieve neutral feel in the helm, perhaps a slight pull into the breeze. A good sign of ideal set-up is if you don’t have to move too much mainsheet. That said, moving mainsheet is important, particularly in changeable conditions, which is why most top teams have the crew playing the sheet. They have two hands to do the job, whereas a helm has only one. As a helm, I don’t touch anything except the tiller. I occasionally act as a human cleat, but Herbie does all the pulling of ropes. My main focus is looking at the water, the next wave.

Waves
A lot more steering and sheeting is required in big waves. You need to be aggressive with your movements so as to get the boat to accelerate. It’s easy to stop these boats, and remember that when you get it really wrong your upwind speed could be 5 knots, but when you get it really right upwind speed could be 15 knots. In flat water, you can sail much closer to the edge of stall, whereas wave sailing requires more variation in your steering and sheeting. All the more reason for the crew to work the sheet.

Gusty conditions
In gusty conditions, set the boat up for the lighter patches rather than the biggest gust. It’s easier to get rid of excess power than look for power in an excessively depowered rig. When you see a gust, wait for it to hit before you react. Always sail into the gust before adjusting Cunningham or anything else. It’s much better to get into the new breeze first. In the initial part of the gust you want to twist the main for acceleration and then haul it back in once you’re up to speed and looking for height again.

The most common mistake
The biggest thing that most cat sailors could do to improve performance is move more mainsheet. I see many sailors just too scared to ease the sheet and then pull it back in again. This is particularly the case when the helm is controlling the sheet. They only have one spare hand, so the temptation is all too strong to cleat the main off. We never use the cleat on our boat, the only reason it is there is for safety reasons downwind when sailing with the spinnaker.

You just can’t sail fast in waves unless the crew is playing the main, so if there’s one skill to focus on, that would be it. You constantly have to be releasing mainsheet to twist and gain speed. Once you’ve got the speed, you can burn some off it with height. But you can’t get height and until you’ve got the speed. As soon as you’re on the edge of losing speed you trim out again and bear off just slightly to keep the efficiency going. It’s a subtle skill, and one that only comes with experience. But on the new generation of cats they respond so well to good trimming that you’ll know when you’re getting it right.

Next week: Hugh Styles gives his views on the latest in spinnaker deployment systems