Light, down-wind speed improvement

[Inquisitor]

I just got back from my first sail boat race. http://www.macgregorsailors.com/forum/v ... =4&t=15746

I wanted to share what I think was a significant speed improvement. For a large portion of the race, we had very light winds that were coming from directly behind. We also had two Mac26M's configured pretty much identically. Mine had the main, 150% Genoa and cruising spinnaker. Mark's had main, 100% jib and cruising spinnaker. At the time, we were both running spinnakers and mains only (no fore sails)... sometimes, wing-on-wing, sometimes not. We were running around 4.3 knots (gps). We were side by side for several miles with no clear advantage being had by either.

I found it tedious. There was a very fine sweet spot for keeping the spinnaker from collapsing and the boat was not totally balanced thus requiring constant attention at the helm while watching the cassette tape tail tells on the shrouds. I could more easily see on Mark's spinnaker the the ripples forming and start losing the edge.

With the main on the same side as the spinnaker, it clearly blocked much of the flow to the spinnaker. Even wing-on-wing, the wind shedding off the mast side seemed to cause a lot of turbulence into the spinnaker. In my opinion, the main can't be set up great for down wind because of swept back shrouds even with a boom-vang and it was also hurting the spinnaker's efficiency.

So here is what we did...

(1) Lowered the main (Mark starts taking the lead)

(2) Whisker pole out the Genoa win-ward. Unfortunately, I broke my homemade one earlier in the day... so I did the following instead.

(2a) Ran the win-ward, Genoa sheet through the ring on the end of the boom.

(2b) Removed the topping lift to let the boom fall.

(2c) Mounted the lower end of the boom-vang on the ring used for the mast raiser's side line.

BTW: This works great when wing-on-wing also. It allows you to both crank down on the main to keep it out of the shrouds and as a preventer to keep from the boom to the windward.

(3) Pulled the Genoa out (furled) via the sheet through the boom's end eye.



The net result was wing-on-wing with the Genoa and spinnaker, with no main to cause turbulence into the fore sail and spinnaker. The spinnaker filled and stayed filled. I believe the Genoa actually helped fill the Spinnaker. We found the setup to be entirely balanced and having a large angle sweet spot. We quickly regained the half-mile lead Mark had opened up while dinking around and passed on by. We were running around 5.5 knots (gps), but I don't know how much of that was improvements or wind speed change. We were decidedly faster.


It would work far better and faster to set up with a whisker pole since you could get the sail out further than the boom's length.



Anyway, I hope someone wins a race using the technique. We didn't because of other gremlin snafus down the course. Mark beat me anyway.

[c130king]

Dennis,

Don't suppose you took any pics of this setup did you? I really hope I get to the Jax Mac so that I can see how you and Mark setup your spinnakers. Want to see that on an and maybe jump on board for a test.

Sounds like you guys had a great time. Hope I can go next year.

Cheers,
Jim
Sailing on König

[Boblee]

Would running the genoa and spinnaker forward of the mast this way cause undue strain on the mast and shrouds? especially if the winds gusted up and especially on 's without a backstay.

[Inquisitor]

Jim,

Unfortunately, I didn't take any. But I'll be trying to refine the process on my POS lakes up here and I'll get some pictures then. I need to refine it as I did have a lot of trouble when I needed to get the spinnaker on the port side because of winds coming heading for the SE and later East. I had one big CF because I started to furl and it sucked in the Chutescoop. That's when Mark pulled back into the lead. I should have pulled the scoop down first and then furled. Live and learn.

Boblee,
At some rediculus wind speed that could be an issue. However, that's the way it always is. I wouldn't be running full sails with spinnaker in 25 knots. Although some of our Oz contingent (with big brass ones) will gladly show pictures in such conditions as if its just another day at the office. We have to be the judge of the conditions and set the sails accordingly... spinnaker or no, full genoa or furled, main full or reefed. I'm suggesting this technique only for those trying to get that extra 10% percent in the sub 10 knot wind range. Plus, It was also far easier to manage than trying to wing-on-wing with the main. When doing it with the main, it was constantly hunting and swaying the boat and semi collapsing and re-filling the spinnaker. With the genoa, it was so balanced and stable I went up on the foredeck and fell asleep.

[THE CUSCUS]

Do your racing "rules" allow the use of 2 headsails for non-cutter rigged boats? The rules I am used to do not allow this and one can even "protest" another boat for putting the jib away "too slow" after launching the spinaker. Also, how did the boat handle with all your center of moment so far forward?

[Inquisitor]

Hmmm! I don't know. That's a good question. I do remember they asked about non-standard things like, "do you run a trapeze?" Guessing... in a race where real awards and points towards a championship are concerned, that might be an issue. With this group... we were merely slalom cones and they'd rather we be faster.

Maybe next year we'll run a duel trapeze off it and see if they mind.


Balance - it was far better balanced. It ran like an arrow. While W-O-W with the main, it felt like it was on the head of a pin. Hunt one way, collapse, then weave the other way and fill.

[bscott]

Wouldn't it be faster and safer to gyb down wind with your Asail and main? Sometimes reefing the main gives the Asail better filling on a DDW run.

Bob

[parrothead]

Even with whisker pole and a working jib instead of a genoa, the double headsail/no main approach described by Inquisitor is a great way to sail an dead downwind. The daggerboard can be fully retracted, there being no side slip to resist, and there's really no steering required [we also pull up one of the rudders, for the ultimate in drag reduction].

That being said, it's only something we consider doing during cool weather, since the apparent wind drops to essentially zero. During the summer on the Chesapeake, feeling a breeze is essential, so we usually do the alternating broad reach approach. I'm not sure if the higher speed truly offsets the longer route, but we don't engage in formal racing, so comfort is the deciding factor.

[Duane Dunn, Allegro]

Ray at BWY had double furlers set up on the X he had previously. There was a 150 genoa on one and a drifter on the other. He would often drop the main and run double headed down wind passing everyone.



http://macgregorsailors.com/modt/index.php?view=281

[Boblee]

Only asked about the amount of strain as it had been discussed here somewhere prior and without a backstay.
It seemed to make sense on an M as all the pressure is taken by the shrouds which with a Genoa and a Spinnaker without the balance of the main would be fairly substantial but then running wing on wing with the main and spinnaker/genoa would also have some forward pressure on the mast?
This OZ sailor doesn't use his spinakker with over 10-15 knot winds thats for sure but it gets a fair bit of use otherwise.

[waternwaves]

I had the double headsails on a 42 lancer I played with occasionally,

required a liberal use of spin/gen poles to keep them full. and we never did it unless we had 15 miles downwind to go. judging by the amount of noise between the two headsails, I am guessing that configuration is not very efficient. and maybe had 60 degress of heading available.

We frequently used the boom as a gen pole. We also bent/broke it when it crashed into the shrouds when the preventer snapped.

[Highlander]

When running down wind with two headsails on an M with no mainsail attach the main halyard to the boom end tighten it then tighten the mainsheet you now have your adj backstay

J

[Boblee]

Yeah I think that was mentioned last time it was discussed Highlander and I have been making sure it is nice and tight since but using the boom as an outrigger would muck that up.
Might see if I can experiment with a pole though sounds good, mind you only have a jib not a genny.

[delevi]

Way to go in being creative to get an extra knot of speed

Another approach would be to pole out the spinnaker luff to windward, like a symmetrical. Not the clew. Clew sheeted to leeward, while the luff is pulled to windward using a foreguy, afterguy, & spinnaker pole, getting the windward half of the spinnaker well clear of the mast and mainsail. This keeps the spinnaker full and efficient, even DDW with full main up. The balance is really nice too and can be used in stronger winds, as long as you are not too high i.e. 150 deg to DDW. Beene and I ran this setup in 15 kts gusting to 25. As long as we stayed around 150-160 degrees, we were doing great. Whenever we tried to go higher, the boat wanted to round. Eventually we had to drop the chute as our course was more on a beam reach. It was fun while it lasted I really love using the spinn as a symmetrical. In fact, I wish it was a true symmetrical. Seems that on our boats, it will blanket at 135 degrees, so it really defeats the purpose of being a downwind sail. BTW, I have a backstay and a heavy duty pole. I wouldn't attempt this setup in a stiff breeze without either of these.

Leon

[beene]

15-25 kts

And 2 pints of liquid courage.

Was a blast

Wish we had taken pics of that setup Leon.

It was a thing of beauty.

G