X-Boat Tuning Guide – Go Fast in all Conditions

Here’s a step-by-step X-Boat tuning guide for speed in all conditions. The measurements are from the online North Sails One Design Tuning Guide and additional unpublished information from Melges.

Set the Mast Rake

Raise the jib and clip the halyard into the adjusting mechanism.

[expand title=”Set the mast rake to 20’11 inches (click for more on how to do this)”]

Clip the mainsail halyard onto the end of a 25′ or longer tape measure.

Pull the mainsail halyard up and lock into place.

Measure the distance from the locked mainsail halyard to the transom of the boat.

Tighten the jib halyard to increase the mast rake, loosen to decrease.[/expand]

Make matching reference lines on the jib halyard and the mast. Label the mast line “Light-Medium.” This is the setting for winds 0-15 mph.

Loosen the jib halyard to obtain a mast rake of 20’10”.

Mark a reference line on the mast with a label for “Heavy.” This is the setting  for winds 16 mph or greater.

Leave the tape measure on the halyard for the next step.

Set the Sidestay Tension

Establish the Base Setting (wind 0-8 mph)

Lubricate the StaMasters with a silicon or teflon lubricant.

With the jib up and mast rake set for Light-Medium, tighten the StaMaster adjusting nuts by hand until the sidestays are very snug (turn counterclockwise to tighten).

Measure the distances from the tip of the mast to the sidestay chain plate on both sides and make sure the distances are equal. If not equal on both sides, adjust the StaMasters by alternately loosening one side and tightening the other side a few flats at a time to make them equal.

Label the base settings on the StaMasters or write down the index numbers on a waterproof card. This is the setting for 0-8 mph.

Medium and Heavy Wind Settings

Medium wind (8-15 mph):  From the base setting, using a wrench, tighten the StaMasters by one index number. For example, if the base setting is 3, tighten to 2. Label this on the StaMasters or write down the index numbers.

Heavy wind (16+ mph):  From the base setting, using a wrench, tighten the StaMasters by 2.5 index numbers.

With the the mast rake and sidestay tension set for heavy wind, the sidestays will be extremely tight. This is good.

Return the StaMasters to their base setting after sailing to prevent stretching the sidestays.

Jib Sheet Leads

The jib sheet leads are moved aft as the breeze builds to flatten the jib. Use a marker or label on the jib track to show these settings:

Light wind: 4 holes showing, counting from the rear of the jib track.

Medium wind: 3 holes showing

Heavy wind: 2 holes showing

Boom Vang

The vang allows the sailor to flatten the sail and also prevents the boom from rising as the mainsail is eased.

Light wind: snug the vang when the mainsheet is pulled in loosely.

Medium wind:  make the vang tight when the mainsheet is fully in.

Heavy wind:  point the boat head to wind and pull the mainsheet in hard. Then tighten the vang.

Adjust the vang if the wind changes dramatically.

Jib Downhaul and Cunningham

Tighten the jib downhaul to just remove the wrinkles from the luff (front) of the jib. The jib foot should just touch the deck along the most of its length. As the breeze builds, tighten further to remove wrinkles and keep the foot low.

Leave the cunningham loose in light air,  pull to take out wrinkles in medium air, and pull hard in heavy air.


Upwind, raise the centerboard slightly as the wind builds to reduce weather helm. Mark these settings on the board box or add an adjustment cleat:

Light wind: all the way down

Medium wind: up 2″

Heavy wind: up 4″

Summary Table

Light Wind (0-8 mph) Medium Wind (8-15) Heavy Wind (16+) Comments
Mast Rake 20’11” 20’11” 20’10”
Sidestays Base setting Tighten 1 number Tighten 2.5 numbers Return to base after sailing
Jib Leads 4 holes showing 3 holes 2 holes Counted from back
Cunningham & Jib Downhaul Cunningham loose; take wrinkles out of jib Take wrinkles out Hard
Vang Taught when main in loosely Tight when main in fully Tight when main in max Adjust if wind changes dramatically
Centerboard Down Up 2″ Up 4″

Sailors Helping Sailors

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