Melges MC Scow Tuning Guide

Most recent update: 6 May 96

Congratulations on your purchase of Melges Sails. The following tuning guide for the MC is the result of many years of sail testing, rig tuning and racing in every conceivable condition. You can follow this guide with confidence, knowing that boats with Melges Sails have won the Inland Championship and National Championship for a number of years in a row.

Before stepping the mast:

1. Clean and lubricate your turnbuckles.
2. Check all pins, wires and fittings for wear.

Tuning the MC is a very simple operation. Once the mast has been stepped into position, attach a tape measure (preferably steel) to the main halyard and hoist until locked into the halyard lock. Measure down to the center portion of the deck at the stern. This measurement will be taken right to the point where the hull and deck meet. The ideal number we have found is 28'-3".

• Upwind 0-10 Knots
• Downwind 0-10 Knots
• Upwind 10-18 Knots
• Downwind 10-18 Knots
• Upwind 18-30 Knots
• Downwind 18-30 Knots

• Upwind 15-30 Knots
• Downwind 15-30 Knots

• Tacking
• Jibing
• Summary

Upwind 0-10 Knots (AP Sail)

Skipper Position: Skipper should sit next to the main sheet cleat, keeping weight forward. Do not use the cleat! Work your sail.
Mast Rake: The mast rake should now be set at 28'-3".
Cunningham: Loose - this keeps the draft aft and sail full for maximum power.
Outhaul: Just pull out all vertical wrinkles. This also keeps the sail full and powerful.
Vang: Loose.
Traveler and Trim: Keep your traveler on the centerline at all times. A general rule for trimming in light air is to have the back of the boom over the back leeward corner of the boat.
Boards: Full down to promote maximum lift and pointing. Top of board should be flush with deck.
Heel: Maximum to leeward without getting any water on the leeward deck. This will reduce your wetted surface area.

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Downwind 0-10 Knots (AP Sail)

Skipper Position: Next to mainsheet cleat.
Heel: Maximum leeward heel to reduce wetted surface - keep the boom kissing the water.
Boards: Leeward board 1/4 of the way down.
Leech Cord: No leech cord! In all of our testing we have found that leech is to no advantage.
Reaching: Everything the same except board should be 50% down.
Outhaul: Ease 1 1/2" in from band

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Upwind 10-18 Knots (AP Sail)

Skipper Position: Standard position.
Mast Rake: 28'-3".
Shrouds: Leave the same.
Cunningham: Just remove the wrinkles, in bigger puffs pull firmly to bend mast and flatten sail. This will help depower you.
Outhaul: Pull to black band.
Vang: When sheeted in going to windward snug the vang so that when mainsheet is eased the boom will not rise abruptly. If you are overpowered, use a firmer vang and Cunningham to depower the sail.
Traveler: Start with traveler on the centerline and drop to leeward accordingly when overpowered to keep the boat on its lines.
Trim: Trim main so that top batten is parallel to boom or 5 degrees twisted off to leeward. Mainsheet should be eased momentarily in the big puffs to keep the boat moving.
Boards: Maximum down to 2" up in order to reduce windward helm and balance the boat. It is especially beneficial to raise the board when there are big waves.
Heel: Keep leeward board vertical in the water.

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Downwind 10-18 Knots (AP Sail)

Skipper Position: Normal position. Sit next to the main cleat.
Heel: Maximum windward heel to reduce wetted surface. This also reduces any chances of nose-diving.
Boards: Windward board 1/4 down.
Leech Cord: None
Outhaul: Ease 1-1/2" in from band.
Cunningham: Loose.
Vang: Tighten enough to keep top batten parallel to boom or slightly twisted off.
Reaching: Everything the same except board should be 50% down.

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Upwind 18-30 Knots (AP Sail)

We recommend our Med./Heavy air sail in these conditions, however if you choose to sail with our AP, the following should keep you sailing fast.

Skipper Position: Skipper in standard position, with crew in standard position if available.
Mast Rake: 28'-3"
Shrouds: The same.
Cunningham: Remove all horizontal wrinkles, in the heavier puffs pull very hard to bend the mast which will flatten the sail and twist open the top batten.
Outhaul: Pull to black band.
Vang: Should be pulled on very hard. Caution should be used tacking and sailing downwind with a firm vang because capsizing will become a greater risk. With the vang on tight, ease your main in the big puffs so the boat stays on its lines. Try not to drop traveler too far for this will hinder your pointing ability!
Traveler: Should be eased from centerline a maximum of 5". This is if you are over powered.
Trim: Trim main very hard. With Cunningham and vang on hard the top batten will never be parallel to the boom. It will be between 10 and 25 degrees twisted off to leeward.
Boards: Maximum down to 2" up in order to reduce windward helm and to balance the boat. It is especially beneficial to raise the board when there are big waves.
Heel: It is important to sail the boat flat in these conditions keeping the leeward board vertical in the water.

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Downwind 18-30 Knots (AP or Heavy Air Sail)

Skipper Position: Sit in normal sailing position. (Next to main cleat)
Heel: Maximum windward heel to reduce wetted surface. This also reduces chances of nose diving. Be careful not to capsize to windward.
Boards: Windward board down 15%.
Leech Cord: None.
Outhaul: Ease 1" in from black band.
Cunningham: Loose.
Vang: Tighten enough to keep top batten parallel to boom. This reduces tendency to rock to windward too far and cause a capsize.
Reaching:
Board: 25-40% down.
Outhaul: To black band.
Cunningham: Loose.
Vang: Medium-Firm. Top batten should be slightly twisted open.

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Upwind 15-30 Knots (Heavy Air Sail)

To achieve the shroud tension we first set the rake at 28'-l". Tighten the shrouds so they are taut, then tighten the forestay so the rake measurement is 28'-3".

This should be your setting at all times with this sail.

Skipper Position: Standard, with crew when it's above 20 Knots.
Mast Rake: 28'-3"
Cunningham: Pull wrinkles out and pull vang firm in the heavier wind to flatten sail and twist open the top batten.
Outhaul: Pull to black band.
Vang: Medium - firm to very firm in the puffs.
Traveler: Start at center and ease a maximum of 5" in order to prevent overpowering or excessive windward helm.
Trim: Trim top batten parallel to boom in 15 Knots. As wind increases vang and Cunningham are applied, batten will automatically twist open as much as 25 degrees.
Boards: Full down to 2" up depending on waves and wind strength. The windier it is and the bigger the waves the further up the board should be.
Heel: Keep the boat flat. (Leeward board should be vertical in the water).

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Downwind 15-30 Knots (Heavy Air Sail)

Same as AP sail in 18-30 Knots.

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MC Scow Special Considerations

Tacking

Light Air: Put new board down when head to wind, don't worry about pulling old board up until you are on the new tack and sailing fast. After the tack, a slight ease and then a trim on the mainsail will help accelerate the boat out of the tack. This should not be done more than once or it could be called cheating. Roll tack the boat.

Medium Air: Same trimming on the boards. You probably will not be able to roll tack any more.

Heavy Air: The new board will now have to be put down before the tack. Don't worry about pulling up the old board until you are hiked out and the boat is at top speed. Again ease the main to help the boat accelerate out of the tack.

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Jibing

Light Air: Lower the new board prior to jibing. Roll the boat through the jibe, pulling the main to the centerline very rapidly and then letting the wind push it out to the new side. Immediately establish proper heel, heading up slightly will help accelerate the boat.

Medium Air: Same as light air.

Heavy Air: Do not lower the new board until after the jibe. This will help eliminate a capsize due to 'tripping' over the new board when the main comes across.

Never jibe when the bow is digging in a wave. Always jibe when surfing down a wave or on a plane.

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Summary:

All these generalizations are norms and averages that have proven fast over many years. Some experimentation on your part may be necessary to fine tune your particular rig and sailing style. Good luck with your new sail and please feel free to call us with any questions you may have.