MASTER YOUR MAINSAIL

KNOWING HOW TO SET UP A MULTIHULL’S MAINSAIL IS CRUCIAL. BRIAN THOMPSON, ONE OF THE WORLD’S MOST EXPERIENCED MULTIHULL SAILORS, SHARES HIS TIPS

- BRIAN THOMPSON

A mainsail cannot know whether it is hoisted on a monohull, a catamaran or a trimaran. The principles of sail trim are universal.

On all types of yacht the traveller, mainsheet, outhaul, halyard and the Cunningham can be used to control the sail, and the information from the telltales can be used to help judge how much power the sail is providing and whether it is well-trimmed.

But there are some important and some subtle differences between monohulls and multihulls.

Because the multihull is so much more stable at low heeling angles, the heel angle is harder to use as a reference for when the boat is overpowered. Rather like a car versus a motorbike; the car heels only a little when pressed, while on the motorbike it’s much more obvious when the limits are being approached.

So on the multihull the decision of when to depower and to reef has to be influenced more by other inputs rather than just heel angle.

Generally speaking, a multihull’s wide beam allows for a much longer traveller than on an equivalent monohull, so there is much better control of the boom position when reaching and downwind sailing. This can make a boom vang/kicking strap unnecessary.