What is a Cam sail?

A Sail has battens that run horizontally across the body of the sail. These give the sail some stiffness and shape. Without battens a sail would be like a big sack, The struts on a Kite Surfing Kite have inflatable battens for the same reason Battens provide shape to a sail. Where the mast is inserted into the sail, this is called the mast pocket. This is the Leading edge of the sail. It is the part of the sail that cuts through the air. You will notice that the mast is not straight, it is swept back. This curve is very important to sail design. The curve is determined by the sail shaping and also by the stiffness of the mast.

The battens are held in place by batten pockets much like the mast is. They may reach all the way to the mast pocket. Often the battens will sit flat against one side of the mast or the other. When the wind blows on one side of the sail the battens will flip around to the other side of the mast.

In a "Cammed" sail the ends of the battens slide into "cams". The cam is like a yoke, it is a "C" shaped device that cradles the mast. In a cammed sail the battens do not touch the mast, they are fixed in place by the "cams". By holding the Batten out and away from the mast, The Batten can be in effect longer, this extra length creates a "bow" shape. Increasing the amount of shape "draught" in the sail. More importantly, it "locks in" this shape. A no-cam sail can also "Fill Up' with wind and create this deep bow shape. But if the air pressure drops on one side of the sail, this shape will be lost. A sail with cams can maintain a more exact shape regardless of the wind strength.

Sails are wings

A sail is basically a wing mounted vertically, a wing is curved, the air passing beneath it has a shorter path to travel than the air passing over it. This creates a low pressure above the wing and a higher pressure beneath it. In this way "Lift" is achieved. With a sail, the lift is turned into forward motion. The more air that passes over the sail the more lift is created. The shape of this surface is very important. Camed sails provide a very exact stable shape for producing forward motion.

Are Cam Sails Better?

It depends on what you are trying to achieve. Wave Windsurfers do not use Cam Sails, leading windsurfing racers do. If want to go fast, then a stable shape is essential. New no-cam sails can still be very fast, but they are not setting any records. The stronger the wind and the more constant the wind strength the less advantage Cam sails will bring. When the wind gets stronger the water often gets rougher, a tough simple and lighter no-cam design sail will be a lot more fun to use in these conditions.

To Cam or not to Cam?

What does Amara Recommend?

While we do use and enjoy No-cam sails up to 9.0M, in general we have found that for sails bigger than 7.5M it is better to use a Cam sail. We like 6-6.5M Cam sails because they can produce the same power as a larger No-cam sail, but we nomally use No-cam sails from 7.5M down if we are not racing or trying to set high GPS times.

Cam sails produce more speed and power than a No-Cam sail of the same size.

No-cam Sails are easier to manoever, change direction, pick-up, rig, lighter to carry and survive surf better.

So we use Cam sails in the larger sizes and No-Cam sails in the smaller sizes, but we break both these rules when we are looking for aspecific advantage.