MacGregorSailors.com

You're right about the jib car, Frank... I just brain-farted that one. Corrected now.

--
Moe

It's a radio station east of the Mississippi River. The ones to the west all start with a K.

WADR = With All Due Respect

http://www.lingo2word.com/lists/acronym_listW.html

Thanks Moe. I've done most of what you suggested, except tightening the forestay. I did tighten the shrouds to get them fairly snug after they stretched a bit. I'm not sure how much tighter to get them. I assume that tightening the upper shrouds will bend the mast back, causing more sail twist. Won't that counteract the tightening of the forestay, however?

I don't yet have sail slugs but plan to get them set up along with halyard leading aft.

As for the traveler, I believe the M is set up the same as the X. I ususally keep it uncleated-letting it move to leeward. Does moving it to winward and easing out the sheet create more sail twist and spill some air?

Leon

Those of us with no traveler use the mainsheet to determine angle of attack on all points of sail, and must use the vang to increase leech tension also on all points of sail.

Those with a traveler system do the same as above when off the wind, but when the boom is within the traveler range, normally use the traveler setting to establish angle of attack, and the mainsheet to control leech tension. However, even here the mainsheet influences angle of attack.

When the car is to leeward, the mainsheet's pull is primarily downward with less inboard. Moving the car to windward and easing the mainsheet back out to get the same angle of attack reduces the mainsheet's downward force, and should allow the boom to ride higher, with less leech tension and more twist in the sail.



As I understand it, the reason for twist is not so much "to spill wind" but is because the wind velocity up high is greater than it is lower. And the higher the wind speed, the greater this difference. For a given boat wind, this moves the apparent wind aft on the upper parts of the sail, and without twist, the angle of attack up there would be greater than at the lower portion of the sail, and the sail would be overpowered up where it has the most leverage to heel the boat. Adding twist to the sail maintains the angle of attack all the way up the sail. [Added on edit]When heading up (or letting the boom out) to check angle of attack, the sail should luff all the way up simultaneously. If the lower portion luffs first, there isn't enough twist. If the upper portion luffs first, there's too much twist. Right?

Am I missing something here? Darren?

--
Moe

delevi wrote: Thanks Moe. I've done most of what you suggested, except tightening the forestay. I did tighten the shrouds to get them fairly snug after they stretched a bit. I'm not sure how much tighter to get them. I assume that tightening the upper shrouds will bend the mast back, causing more sail twist. Won't that counteract the tightening of the forestay, however?

The forestay primarily determines mast rake. The bend is established by the upper shroud pulling the mast aft above the point where it's pushing the swept back spreaders (and hence the mast) forward. However, the forestay being attached at the spreaders also contributes some.

The bend doesn't really control twist. It does, however, pull some of the draft out of the middle of the sail. Those with an adjustable backstay can control the bend. BTW, I don't believe a backstay that doesn't interfere with rotation is an impossiblity on an M. I believe Brent will need one on his future M for his Hawaii trip.

delevi wrote:I don't yet have sail slugs but plan to get them set up along with halyard leading aft.

With the friction of a boltrope in a cove, I don't see how, especially without a cunningham, that a halyard alone can get good luff tension. A roller furled jib is sort of in this situation, but has the advantage of not having to be raised and lowered. The luff tape can be nursed along in the foil. And while I won't call it a cunningham, the jib can be tightened in the foil not only by the halyard, but at the tack as well.

I should've also asked if you're using the MacGregor recommended (at least in the X owner's manual) trucker's hitch in the halyard above the cleat to get a 2:1 pull on it.

delevi wrote:As for the traveler, I believe the M is set up the same as the X. I ususally keep it uncleated-letting it move to leeward. Does moving it to winward and easing out the sheet create more sail twist and spill some air?

See my post above about this... it's how I understand the physics. Most of us with an don't have a traveler, although a few have added one.

--
Moe