Catamaran Racing Association of Michigan

Sailing 101

Sailing your Catamaran fast and in the right direction


First off, there are a lot of adjustments to play with on a modern cat. However, like many things, 90% of your speed potential is determined by 10% of the adjustments. We’ll focus on that 10% here. The tiller, main, and jib are the primary 3 controls that a beginning racer needs to worry about.


  Upwind
  Light Air – up to 5 or 6 kts Medium Air ~ 7-12kts Heavy Wind ~13kts+
Tiller Steer so the Apparent WindApparent WindDefinition: Apparent Wind is the wind the boat experiences as it moves through the true wind. This would be the direction and strength of the wind you feel on your cheek or the direction the wind indicator points as you’re sailing.True Wind is the direction and speed of the wind over the water. This is what you see on the flag of an anchored boat or the ruffles on the water.When you’re stopped, true wind and apparent wind are exactly the same. Think of riding a bike on a calm day. As soon as you start moving, the apparent wind is the breeze you feel on your face from your own speed. If there is a small breeze coming from the side, your forward speed gets added to the wind speed, and the apparent wind shifts forward (toward the front of the boat) compared with the true wind. The faster the boat goes, the further the forward shift. As an example, a boat sailing 10kts sideways to the true wind (a 90deg beam reach) in a 10kt breeze will see an apparent wind of 12kts at about 45deg. If the boat speed increases to 15kts, then the apparent wind increases to 18kts and its angle decreases to 33deg. The boat would feel like its pointing (close to the wind) even though it’s on a beam reach relative to the true wind. The magic of apparent wind: As you can see, part of the boat speed gets added to the true wind speed. This can create a virtuous cycle that will continue until the apparent wind shifts too far forward or the drag on the hulls starts to dominate. Low-drag boats like catamarans can therefore go faster than the wind on some points of sail! Super low-drag ice boats can manage more than 4X the speed of the wind in certain conditions. Imagine that on a blustery 20mph winter afternoon! Catamarans are more modest, and the capability depends on the boat design. Most are in the 1.2 to 1.8x range on a beam or slightly deeper reach....
starts out at about 35-40°. Once the boat gains some speed you can slightly head up a bit. Steer to the jib telltales. The LuffLuffDefinition: The Luff is the forward (leading) edge of the sail...
side should be steady streaming back and the back side should be slightly lifted – up to 45°, but not dancing.
Same as Light Air Steering is similar to before. Try not to PinchPinchDefinition: Pinching involves sailing a boat too close to directly upwind.  The boat may continue to sail, but it is not the optimal or fastest heading....
or feather too much - its slow.
Jib Tighten (sheet-in) jib so the LeechLeechDefinition: The Leech of the sail is the aft or trailing edge....
of the jib follows the contour of the main. Don’t over-sheet and close off or choke the SlotSlotDefinition: The Slot is the area between the jib and main where air is funneled through, helping to give additional suction (lift or forward thrust) to the backside of the mainsail.  If the slot is too open, then the air is not sped up enough to give maximum lift.  If the slot is too closed, then it gets "choked" which also greatly reduces the available suction/lift....
. Sheet in slightly in puffs and relax in lulls.
Tighten (sheet-in) jib firmly. However, don’t oversheet and make the bottom curl. Jib sheet tension should be adjusted as wind strength changes (firm up in puffs, and a little-bit looser in the lulls). Super tight, as flat as possible
Main The traveler should be centered. Main sheeted so upper 2-3 LeechLeechDefinition: The Leech of the sail is the aft or trailing edge....
tell tails just start to play peek-a-boo behind the mainsail, then sheet out a bit so they stream back. Keep testing the telltales to verify proper trim. Firm up the main just a bit in puffs and relax in lulls.
The traveler should be centered. The main sheeted so upper 2-3 LeechLeechDefinition: The Leech of the sail is the aft or trailing edge....
(trailing edge) tell tails just start to play peek-a-boo behind the mainsail, then sheet out a bit so they stream back. Keep testing the telltales on main and jib to verify proper trim. Firm up the main as the boat speed increases.
Sheet the main hard and use the CunninghamCunninghamDefinition: The cunningham is a type of downhaul used to change the shape of a sail.  Tightening the cunningham reduces the camber (or fullness) of the sail, reducing drag in heavy air.  It can be a very effective adjustment to manage the power of the mainsail.The cunningham differs from a typical downhaul in the way that it attaches to the sail. The system usually consists of a line which is secured at one end to the mast or boom below the foot of the mainsail. It is then passed through a cringle in the luff of the sail near the foot, but above the tack, and then led down on the other side to a fitting on the mast or boom or on the crossbar....
and OuthaulOuthaulDefinition: An outhaul is a line that runs from the clew (the back corner of the sail) to the end of the boom and used to control the shape of the curve of the foot of the sail.  Tightening or slackening the outhaul can flatten or fill out the sail, shift the draft forward or aft, change leech and foot tension, and increase or decrease camber....
as needed to flatten the sail. The cunningham is very effective in depowering the main. If the crew is strong, have them continuously adjust main sheet tension to spill wind in the puffs. If this is not enough, the skipper can also travel out the main and/or feather into the wind as necessary.



  Downwind
  Light Air – up to 5 or 6 kts Medium Air ~7-12kts Heavy Wind ~13kts+
Tiller Your average course should be about 45° from straight downwind, but prioritize on following the Apparent WindApparent WindDefinition: Apparent Wind is the wind the boat experiences as it moves through the true wind. This would be the direction and strength of the wind you feel on your cheek or the direction the wind indicator points as you’re sailing.True Wind is the direction and speed of the wind over the water. This is what you see on the flag of an anchored boat or the ruffles on the water.When you’re stopped, true wind and apparent wind are exactly the same. Think of riding a bike on a calm day. As soon as you start moving, the apparent wind is the breeze you feel on your face from your own speed. If there is a small breeze coming from the side, your forward speed gets added to the wind speed, and the apparent wind shifts forward (toward the front of the boat) compared with the true wind. The faster the boat goes, the further the forward shift. As an example, a boat sailing 10kts sideways to the true wind (a 90deg beam reach) in a 10kt breeze will see an apparent wind of 12kts at about 45deg. If the boat speed increases to 15kts, then the apparent wind increases to 18kts and its angle decreases to 33deg. The boat would feel like its pointing (close to the wind) even though it’s on a beam reach relative to the true wind. The magic of apparent wind: As you can see, part of the boat speed gets added to the true wind speed. This can create a virtuous cycle that will continue until the apparent wind shifts too far forward or the drag on the hulls starts to dominate. Low-drag boats like catamarans can therefore go faster than the wind on some points of sail! Super low-drag ice boats can manage more than 4X the speed of the wind in certain conditions. Imagine that on a blustery 20mph winter afternoon! Catamarans are more modest, and the capability depends on the boat design. Most are in the 1.2 to 1.8x range on a beam or slightly deeper reach....
angle of about 90°. As boat speed picks up, steer down to keep Apparent WindApparent WindDefinition: Apparent Wind is the wind the boat experiences as it moves through the true wind. This would be the direction and strength of the wind you feel on your cheek or the direction the wind indicator points as you’re sailing.True Wind is the direction and speed of the wind over the water. This is what you see on the flag of an anchored boat or the ruffles on the water.When you’re stopped, true wind and apparent wind are exactly the same. Think of riding a bike on a calm day. As soon as you start moving, the apparent wind is the breeze you feel on your face from your own speed. If there is a small breeze coming from the side, your forward speed gets added to the wind speed, and the apparent wind shifts forward (toward the front of the boat) compared with the true wind. The faster the boat goes, the further the forward shift. As an example, a boat sailing 10kts sideways to the true wind (a 90deg beam reach) in a 10kt breeze will see an apparent wind of 12kts at about 45deg. If the boat speed increases to 15kts, then the apparent wind increases to 18kts and its angle decreases to 33deg. The boat would feel like its pointing (close to the wind) even though it’s on a beam reach relative to the true wind. The magic of apparent wind: As you can see, part of the boat speed gets added to the true wind speed. This can create a virtuous cycle that will continue until the apparent wind shifts too far forward or the drag on the hulls starts to dominate. Low-drag boats like catamarans can therefore go faster than the wind on some points of sail! Super low-drag ice boats can manage more than 4X the speed of the wind in certain conditions. Imagine that on a blustery 20mph winter afternoon! Catamarans are more modest, and the capability depends on the boat design. Most are in the 1.2 to 1.8x range on a beam or slightly deeper reach....
at 90°. Steer down in puffs and head up a bit in lulls.
Same as Light Wind Speed is your friend - you have to keep it up to keep the boat manageable. After the bear away, its better to sail deep at first and then slowly head up to “heat it up”. Again, keeping boat speed up is important as it will actually reduce the apparent wind speed and make the boat feel more manageable.
Jib Sheet-out jib quite a bit so the tell tales on windward side of the jib luff start to dance and then sheet in just a bit to get them to smooth out. To sail fast, this should be continuously adjusted as wind speed and boat speed vary. Tell tales on back side should always be streaming back (not dancing). Same as Light Wind Same as Light Wind
Main Set the traveler out to roughly 6” in from hull. The Main shoudl be sheeted so upper 2-3 leech (trailing edge) tell tails just start to play peek-a-boo behind the mainsail, then sheet out a bit so they stream back. Keep testing the telltales to verify proper trim. Firm up the main as the wind increases in puffs. Set the traveler out to roughly 6” in from hull. Main should be sheeted out so the leech (trailing edge) tell tails are flowing smoothly and then sheet in just a tad. The main sheet should not be cleated and continuously adjusted if you want to go fast. Set the traveler out to roughly 6” in from hull. Continuously adjust main to be sure you have good backside flow (not stalled). You will need to actively sheet in as you heat it up. Head downwind in the puffs – this is counterintuitive at first, but if you try to head up, you’ll surely swim. Daggers should be raised about half way.