G'day,

Rudders at 90 certainly slow it down, although nowhere near as quickly as sails at 90. Both waste inertia/energy/whatever it is that keeps you going forwards. With a bit of practise, we will kill the speed by luffing head to wind. Unlike a cat, where this is done as quickly as possible to maintain momentum through the tack, on a proa it can last a lot longer. Once the boat is stopped or nearly so, then rotate the rudders, sheet on the aft sail, move crew forward and spin it round onto the new tack as quickly as possible. Maybe not as good vmg as a cat, but should be close, with no chance of getting into irons.

Regards,

Rob