In order for your MacGregor to perform to its potential, you must keep your rig (mast, shrouds, and stays) properly tuned.  These suggestions are designed to give you an idea of how to shape and tension your rig.  Included are some notes on specific sailing conditions and various boat models.

For these instructions, we are assuming that you trailer your boat and want to be able to easily pin the headstay when raising the mast.  The additional performance gained by making the rig tighter than we are suggesting is small -- and the additional hassle is a trade-off not many people want.


The main terms used on these pages about rig-tuning:

Shrouds:   The wires that run from the sides of the boat to the mast.  MacGregor's have four shrouds -- an upper and a lower shroud on each side.  (The forestay/headstay and the backstay are not called shrouds in this context.)

Lowers:   The shroud on each side that goes from the deck to the point at which the spreader meets the mast.

Uppers:   The shroud on each side that goes from the deck through the ends of the spreaders and then attaches to the mast.  At the top on M19 & M22, about 4 feet below the top of the mast on most other Mac's.

Spreaders:   The aluminum tubes extending away from the mast, about halfway up, that hold the uppers away from the mast.

Headstay:   The wire from the bow of the boat to a point near or at the top of the mast.

Forestay:   Another word for headstay.

Backstay:   The wire from the stern of the boat to the top of the mast.

Fractional rig:   A boat on which the headstay attaches to the mast below the top.  The M26, M26x, and some M19s are fractional.

Masthead rig: A boat on which the headstay attaches to the top of the mast.  Most M19s are masthead rigged.

Other terms you may hear in advanced tuning guides:

Partners:    Small wedges used to position the mast where it goes through the deck on a boat with a keel stepped mast.    Many larger, non-trailerable boats have masts that go through the deck and sit on the keel, books about tuning may talk quite a bit about the partners, but you don't have to worry about this, no Macgregor (except the 65!) has them.

Hounds:    The point at which the headstay attaches to the mast, especially in fractional-rig boats.  We refer to this fitting as the Headstay Tang.

Mast Position:   Mast position is the angle of the mast (fore and aft) relative to the top of the deck with no bend in the mast.

Most MacGregors sail well with about 3-6 degrees of aft rake.  (That is, the mast is slanted backwards slightly.)  If your boat tends to round up (tack by itself) in a stiff breeze, shorten or tighten the headstay to bring the mast tip forward (less rake).  If it turns away from the breeze, lengthen the headstay.

Mast Bend (General)

MacGregor masts, like most aluminum masts, are meant to bend somewhat (with the middle of the mast curved toward the bow of the boat).  By changing the amount of bend, you can change the way the boat sails. Note: The 26M sets up with the mast nearly straight.  

Mast Bend (Light-Wind Areas)

The mast should be almost straight (very little bend).  Tighten the lower shrouds to pull the middle of the mast aft -- but never so much that you pull it beyond straight.  Even for the lightest-wind areas, the mast should always bend at least a little bit.

Mast Bend (Heavy-Wind Areas)

The center of the mast should bend 2-3 inches forward of a chord from the mast tip to the mast step.  (To help see mast bend, you can pull the mainsail halyard tight to the where the back of the mast touches the mast step on your deck.)  To push the middle of the mast forward, tighten the upper shrouds.  You may need to first loosen the lowers a bit if the rig is already fairly tight.

Backstay Tension

Masthead boats:

If you don't have an adjustable backstay, make the rig as tight as you can put up with when pinning the headstay.  This minimizes headstay sag and improves upwind performance.

Fractional-rig boats:

The backstay should be just snug for normal sailing.  (On a fractional rig, the backstay contributes very little to headstay tension.)  On windy days, if you have an adjustable backstay, tighten it an extra inch or so in induce mast bend.  (This flattens the mainsail a bit and also spills some wind from the top of the sail, both of which will make the boat heel less.)


How Tight Should The Rig Be?

This is somewhat subjective.  A good rule of thumb for easy trailering plus good performance is that the shrouds should be tight but not quite tight enough to "play music" on them.  If it is very difficult to pin the headstay when you raise the mast, the rig is probably tighter than it needs to be.  The balance of tension between the upper and lower shrouds is determined by how much bend you are trying to preset into the mast.

Alignment Side to Side

The procedure described here should work well for anyone but the hard-core racer (who's likely looking for that last 1/16 inch, that extra 1/10 of a knot).  

Make certain that the upper shrouds are in the same holes in the adjusters on each side of the boat before you start.  

Sight up the sail slot in the back of the mast; if it appears straight, you're home free.

If the mast bows left in the center, you need to tighten the starboard lower and/or loosen the port lower.

If the mast bows right in the center, you need to tighten the port lower and/or loosen the starboard lower.

Boat Specific Notes

MacGregor 19:

You may need to have the uppers tighter than the lowers in order to keep some bend in the mast.

Typical mast rake is 6-8 degrees (more than most trailerables).


MacGregor 26 daggerboard:

Shorten the headstay to the limits of the turnbuckle or adjuster.  This will reduce helm pressure, these boats are really fast, but very prone to weather helm.

MacGregor 26X:

Typical mast rake is 7-10 degrees (a lot more than most trailerables).

MacGregor 26M:

The new airfoil mast on the M is very stiff, and sets up very straight as it is really hard to bend it very much.

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