Sailing downwind on an M

[delevi]

With the swept back spreaders of the , the main sail can only be let out so far until it hits the spreader and shrouds. I wonder what your experiences are when sailing down wind; broad reach to a run. Do you let the main get split up into several pieces of sail while pressed up against the rigging? This seems to be a very ineffective sail shape, not to mention chaff on the sail. An option I tried which seems to work fairly well is to drop the vang, tighten the leech line & sheet in just so the sail barely touches the spreader. This gives the top part of the sail enough twist so it catches the wind at the appropriate angle, while the lower part, granted not at optimum sheeting angle, still has a deep draft. I noticed other boats implementing this tactic but they seem to achieve much more sail twist. Not quite sure if I can duplicate this on a Mac. My method also goes against common teaching of sheeting in the vang when sailing downwind. I tried sheeting the traveler to windward, while compensating by letting out the mainsheet. I did this to add twist, but the boat slowed down, so I dropped the traveler back to leeward. Any tricks & techniques you guys find effective?

[Richard O'Brien]

I just recieved my copy of Good old Boat, and they had a very good article on apparent wind. Basically they said that the taller the mast, the less friction from the water, and thus more sail twist. I think that you have to see the diagrams to understand how they arrived at this, but i'm guessing most of the other boats have taller rigs, EH, Delevi?

[Steve K]

Not sure, but I think when sailing downwind (speaking of dead downwind here) sail shape becomes less important. You're no longer creating lift with the sail. You are more concerned with how much sail area you can present to the wind and catch as much, or enough to pull the boat as fast as possible (which when sailing dead downwind is usually the wind speed itself, minus the inherent drag of the hull, foils etc.).
If going downwind, but slightly off the wind, of course other rules apply, that would bring sail shape back into play.
As I said @ first, I'm not positively sure all this is correct.

I never noticed any wear on my mainsl where I let it touch the spreader tip, when running. I usually tried to keep it off the spreader with the sheet and keep the vang on, so the boom would not lift at all. I would usually rig some kind of makeshift preventer also.

Other experiences, when running.
The boat is great set up wing on wing with the headsl poled out, centerboard (or dagger board as the case may be) raised completely. This will make your speed better in very light wind and if going fast, the boat won't wallow and be easier to keep pointed straight down. Actually keeping the centerboard up makes it easier to keep her pointed straight down at any speed. You can even raise one rudder (not sure here with the M boat), if you are moving pretty well. If just ghosting keep both rudders down or steerage could be lost.

I like to run one of the canyons that connect two of the large basins @ Lake Mead, as I describe above. (giant wind tunnel with 500 foot cliffs on each side, wind always in the same direction) Never touched a sail control and hardly had to correct steerage at all a time or two. It's an hour or more of just sitting in the cockpit, watching the cliffs go by. Darn near fell asleep once .
It's strange to sail this area. You look ahead and see the canyon making a sharp left turn. You think about changing sail settings, but the breeze follows the canyon and your boat follows the breeze, when wing on wing. 'Course, when the canyon opens into the next basin, you have to be prepared and think (and move) fast, 'cause you never know what kind of turbulent air you're sailing into. Quite the training course, particulay if single handed, as I always seem to be.

[delevi]

i'm guessing most of the other boats have taller rigs, EH, Delevi?

Yes, about 30-40' boats

I like to run one of the canyons that connect two of the large basins @ Lake Mead, as I describe above. (giant wind tunnel with 500 foot cliffs on each side, wind always in the same direction)

Sounds like an awesome palce to sail Steve

[NautiMoments]

When sailing down wind I was taught, by several racers in our MacGregor Club, to present as much sail to the wind as possible. Them main is out as far as practicle, against the spreaders but not enough to do any damage. The foresail is out the opposite side and I made a Whisker pole, out of a modified extension paint pole, to keep it as tight as possible. The center board or dagger board is up. Got to remember to put it down before you are about to change direction around a marker though. The Mac is not a down wind boat and sometime a person tacking out and back on a broad reach would beat you.

[baldbaby2000]

I usually let it out so it touches the spreaders. I have rubber boots on the spreader ends and plastic sleeves on the shrouds to keep the sail from getting damaged or stained. The best point of sail tacking downwind is generally considered to be a function of wind speed. The most efficient angle at 15 knots of wind probably isn't the same as when the wind is 5 knots. Using my VMG indicator usually sailing at 135 degrees is too high and I'm better off heading down farther to the point where the headsail just starts to get blanketed a little by the main.

[Catigale]

Classic way to round up is to be running with a decent wind of 15-20 mph, making hull speed (7mph about) and then turning onto a beam reach. When you are running your apparent wind is only 20-7 = 13 mph, but the moment you turn onto the reach the boat sees the full 20 mph and over you go....

BTDT

[Tom Spohn]

On the M, the first step is to run the control line from the vang back to the cockpit through blocks attached to the underside of the boom. If the vang is run to the deck and then back through blocks fixed to the deck it will defeat the mast rotation feature.

When going down wind you will get the best speed by going on a broad reach rather than running. In gusty winds and almost gusty winds this is also a lot safer and more relaxed than being constantly on-guard for an accidental jibe. Put on lots of vang as the traveller does not have enough range to matter. Pull up the center board and lift the windward rudder--but remember to put them down again when you need to change direction. The sail can be let out till it touches the spreader. Remember that twist, sail shape, etc. does not matter as much as just getting the maximum area in front of the wind.

[Bill at BOATS 4 SAIL]

Tom - You shouldn't have to attach the vang to the deck on the 26M. It has a plate at the base of the mast that sticks out the back with a hole in it. I put a 5/16" eye-bolt there and attach the vang to it, similar to the bail on the 26X.
I put a snap-shackle on the bottom fiddle block, so that I can remove it easily, for use as a preventer, by attaching it to a stanchion base.
Or, to attach it to the bail the mainsheet is on, to get it out of the way, if I don't want to use it. This is where I put it for trailering. You might need a longer line for this.

[Tom Spohn]

Bill,
I agree. I guess I was making the point that if you ran the vang the way most folks do on the X, which is to the base of the mast then to a turning block and then back, you will wind up with a mast that won't rotate.

[Terry]

Tom,
Are you saying that the block with the cleat end should be attached to the boom so that when one tightens the vang they are pulling along the boom as opposed to the cleat end being attached to the base plate of the mast and then pull along the cabin top?

[Bill at BOATS 4 SAIL]

This is another one of the personal preference items.
You go to some marinas and all, or most, of the boats with vangs, have the line coming off the top block, while at another marina it's coming off the bottom block.
I prefer to have it coming off the bottom block, like the mainsheet.

Try doing it the other way than you do now. You may find you prefer to do it that way.

[kmclemore]

This is another one of the personal preference items.
You go to some marinas and all, or most, of the boats with vangs, have the line coming off the top block, while at another marina it's coming off the bottom block.
I prefer to have it coming off the bottom block, like the mainsheet.

Try doing it the other way than you do now. You may find you prefer to do it that way.

I also prefer having it come off the lower block, for three reasons. First, you can get better leverage pulling against the fixed mast base; second, when you are pulling against the mast you're getting an actual measured pull down on the boom, but whereas when you pull down from the boom you're distorting the amount of adjustment by your pulling down and this then subsides after you cleat-off the vang; and third, the remaining line is easier to keep tidy on the deck.

And actually, my other sailboat, a BW Harpoon, came set up that way from the factory as well.

[Tom Spohn]

Mine came off the bottom as Bill prefers. However, I removed the cam cleats completely from the vang assembly. From the bottom block I ran the line back to the underside of the boom where a small block was located just aft of the vang attachment. From there the line ran back through a few fairleads and then through a clam cleat about two feet from the end of the boom. The Clam Cleat is the type that has a bar (keeper) across the opening which is necessary to keep the line from falling out. Finally the line passes through a small block on the bottom near the end of the boom. To apply vang simply pull on the line coming off the block at the end of the boom. To release vang grab the small section of line between the block and the clam cleat and pull down from the clam cleat to release. This is way harder to describe than to draw it.

This idea came from a discussion with Todd at BWY at a boat show two years ago and was scribbled on the back of a flyer. Todd has since improved on the idea--or at least made it neater by running the line inside the boom--very tidy, but I did not have the means to cut a rectangular slot into the bottom of the boom and just ran mine back under the boom. Incidently the Perla Noir has a Cunningham run inside the boom as well.

Clam Cleat

[Frank C]

Same idea for my outhaul, Tom. But the problem with boom-lines (IMO)
is that it's a continuing hassle to keep the tails ship-shape. This one is
coiled into a velcro strap just under the flaked mainsail leech.

3:1 Outhaul Tackle