Typically when looking at sailing conditions, wind speed and then wind direction are the primary considerations. For most mono hulls winds around 20 knots blowing from near the beam are going to give you maximum speed. Many times wave height/sea state is a secondary consideration. While flat water might be best, big waves are not too detrimental.

With the advent of the giant Race Class cats, sea state has become a primary consideration. Geronimo skipper Olivier de Kersauson says, “You go as fast as the weather allows. If there’s a way of covering 580 for 600 miles, you cover 580 or 600 miles.” In other words if there’s plenty of wind plenty of speed will follow. These boats are really apparent wind machines so they achieve greater speeds with less wind than mono hulls.

Olivier de Kersauson also says, “Impact is very destructive. It slows the boat first, but the rigging is still moving fast. It’s that kind of impact that can break your equipment. You have to be careful.” While you may not break a race class cat by sailing too fast, you may damage one by hitting seas too hard. Composite materials can take the 30 knots of speed, but not the wave impact.

Recently ODK made this observation, “5 or 6 hours the sea will be rougher and we can’t maintain this speed in seas that rough.” From onboard Cheyenne watch captain Brian Thompson reported, “It has taken at least 18 hours for the sea state to moderate a little and this has been limiting our boat speed.”

The first generation of Race Class multi hulls has made it clear that avoiding contact with the waves is paramount. For this reason
the newest cat Orange II has bows that are 3.3 meters off the water at the bow. Also the beams that connect the hulls actually sit on top of the hulls. It’s been learned that more clearance is equivalent to more speed.

The need for smaller seas to gain maximum performance adds a new element to routing and navigation. Where as waves may once have been a small factor, they not maybe more important than wind speed.

Usually a forecast has wind direction and speed first, which is then followed by wave height. Sitting in the nav station of a giant multi hull you might be more concerned with the part of the forecast that says, “Seas 5 to 8 ft building
to 7 to 13 ft” than the Sw winds 15 to 25 kt increasing to 25 to 35 kt. You know how to deal with more wind- by shortening sail. However, these boats have not yet figured out how to handle seas without slowing. And when you absolutely, positively need a 600 mile day, it’s flat seas you want.

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