YOUR PERFECT DOWNWIND SAIL

HOW TO SET UP YOUR BOAT FOR SMOOTH, STRESS-FREE DOWNWIND SAILING: RACHAEL SPROT EXAMINES THE OPTIONS

For the coastal sailor, upwind sailing skills are critical: there's nothing like a lee shore to focus the mind on tacking angles and leeway. For the ocean sailor the challenges are VMG, handling swell and avoiding a crash gybe, but ongoing developments in hull, rig, sail and hardware design have generated huge variations in how we do this. There's a confusing array of kit and tactics to choose from, so it's important to spend time on research before spending money on equipment.

The first rule of any big decision is to know yourself, your boat and your crew. Neil Mackley, of North Sails, explains: "The thing I most enjoy is sitting down with people and finding out about them. Are they comfortable handling a pole? Are they happy working on the foredeck or would they prefer to manage things from the cockpit? How much stowage space do they have?"

When it comes to the boat, one of the most important metrics is the efficient downwind sailing angle. Broadly speaking, light, flat-bottomed, modern yachts will sail much faster on a reach than on a run. Comparing the new Swan 48 with its predecessors illustrates these changes: the current model is 14% faster on a heading of 120° TWA than 150° TWA. The previous generations only have a 7% difference (see table, above right).

Scrutiny of the polars for the 1995 Frers Hallberg-Rassy 46 gives a similar picture. When flying a spinnaker in 14 knots it makes 7.1 knots on a TWA of 165° and 8.4 knots on a TWA of 120°. The extra 1.3 knots accumulate to a 400500-mile gain over a transatlantic passage, but the 45° difference in angle will cost far more in extra distance.

Heavy-displacement, traditional cruisers won't make exponential gains by reaching. "Wherever possible I run the data through a velocity prediction program to find out where the sweet spot is," Mackley says, "and for most cruising boats it pays to sail deep."