Light weather mains?

genieskip · #1 (**permalink**) 02-18-2010

A recent article I "Good Old Boat" tweaked my interest. The author had a sailmaker make him a mainsail out of light nylon spinnaker cloth to be hoisted in light winds. I had thought of this many times while racing and slatting about in big slop with little to no wind. As the article's author pointed out, this can be more damaging to sails than harsher weather.

Let's face it, cruising sailors, unless faced with major crossings where fuel is rationed, will, 99% of the time, drop sails and hoist the iron jenny under light conditions - or drop sails altogether and go swimming or fishing. What if you had a light main that you could hoist and could do as much better than the main as a drifter is an improvement over a genoa? On boats in the 35' or greater area the cloth of a main is 7 oz or better, much to stiff to catch zephyrs. Imagine how 3/4 oz nylon would stay filled in just a few knots of wind.

The two main advantages of the light weather main is that it really save a lot of wear and tear on the main and makes you go much better in those conditions. I can testify, as I am sure we all can, of the unease we feel as the mainsail droops loosely, only to be filled with a bang when a wave rocks the boat and suddenly fills it with the wind created by a roll to one side. Repeat on other side. Repeat again. And again. Etc.

Has anyone out there had experiences with this kind of sail? I'd like to hear from others before having Sailrite design and cut me a kit and spending the time and effort to sew it up. There is also the little problem of putting up another track, though I plan to do that for the trysail anyway.

sailingdog · #2 (**permalink**) 02-18-2010

The problem with many boats isn't the weight of the sails, but more the drag of the boat. My boat does just fine with its normal main in light conditions, but I've got a lot less drag than most boats...

AdamLein · #3 (**permalink**) 02-18-2010

So, given how expensive it would be to reduce my boat's drag to the point where it's comparable to SD's (and btw, I suspect the inertia of the ballast is probably an even bigger problem than aero- or hydro-dynamic drag at low speeds), maybe talking about alternative mains is not a bad idea

So yeah I could see a lighter main being helpful. Other than the hassle of bending on a new main (twice), I don't see any major downsides. However I can see another issue besides cloth weight that affects your ability to fill your main in light air, and that's mast profile. At least on my boat, the mast is quite wide, so airflow has trouble attaching to the luff.

Therefore might it not also be a good idea to find an alternative rig as well? Perhaps hoist your light-air main as a lateen rig with a very narrow spar that wouldn't get in the way of the air so much. On the other hand, it might move the center of effort too far aft and thus produce too much weather helm.

Just some thoughts.

bubb2 · #4 (**permalink**) 02-18-2010

I don't understand how this would be improvement over an Asymmetrical. When I get into light air. I host the 3/4 oz Asymmetrical. If I can't keep the main filled I will douse that. I would not be able to point as high but I can still make progress to windward. In my particular circumstances, I have lazy jacks with a stack pack sail cover. It does not lend itself to changing out the main sail. The Asymmetrical, I can rig and host and have flying in 5 min. Changing a main sail every time you run into light air sounds like a hassle to me.

zz4gta · #5 (**permalink**) 02-18-2010

I think a light air main would be better made out of very light dacron. Nylon is going to stretch a lot without much load, making it really hard to trim.

Removing weight in the boat and aloft would be much cheaper (free) and less time consuming. Are you're halyards stripped? Is the bildge dry? Do you have cruising gear aboard when you're just daysailing? How is the rig tuned? Is the bottom faired and burnished?

Also, you'll have to define "light" air. Light in HI is different than Ches Bay "light".

Allanbc · #6 (**permalink**) 02-18-2010

You could rig it as a loose footed main. The normal main would be down so it could be hoisted in that sail track. It isn't a high performance sail so a somewhat sloppy rigging isn't that big of a deal.

mike dryver · #7 (**permalink**) 02-18-2010

i thought in the article that genieskip is talking about the owner had the sail made from 1.5 ounce material. also the sail was only attached at the head, tack and clew which in the pics shows the main just stowed. the only thing you have to do is move the hoist over to the light air sail after securing the tack and the clew of same. the other thing is you need to have to have a separate out haul for this sail so you can adjust sail shape better i would think. i would think that a 3/4 ounce sail would be to light for this and stand up to popping to often when filled

bubb2 · #8 (**permalink**) 02-18-2010

Quote:

Originally Posted by mike dryver

i thought in the article that genieskip is talking about the owner had the sail made from 1.5 ounce material. also the sail was only attached at the head, tack and clew which in the pics shows the main just stowed. the only thing you have to do is move the hoist over to the light air sail after securing the tack and the clew of same. the other thing is you need to have to have a separate out haul for this sail so you can adjust sail shape better i would think. i would think that a 3/4 ounce sail would be to light for this and stand up to popping to often when filled

This makes more sense to me. It's rigged like a storm sail, only for light air.

MtHopeBay · #9 (**permalink**) 02-18-2010

It WAS on a seperate outhaul and attached at the 3 corners only. It also used very light line for halyard and control lines, 3/16 I think. The light-air main was used in conjunction with a spinnaker not in lieu of it.

I think the main reason for the light-air main was the beating the heavier main takes from "slatting" as the OP mentioned. It was an interesting article but the pretty picture of the colorful sails all filled out in light air is the best selling point. White sails are so...white.

genieskip · #10 (**permalink**) 02-18-2010

A lot of good points. Memory could have failed me and it might very well have been 1 1/2 oz nylon (loaned my copy of the GOB to a friend so I couldn't check). You are probably right about the weight of the cloth.

The asymmetrical is for the fore triangle so it really doesn't need to enter in the discussion. The problem is when you have a light sail in the fore triangle and a heavy one aft of that. Yes, you can drop the main, or you could start the engine or take a nap (and I have done all of those - I didn't mean it facetiously). I'm thinking of how to keep sailing when the wind drops to just a few knots.

The sail should be free on the foot and the clew could be attached to one of the reefing lines that on my boat exit the boom at its after end with the other end led to the cockpit. It probably can be free on the luff as well if the halyard can be tensioned good and tight with either wire or spectra at the luff. Or maybe dacron line in the luff so you can tension to control sail shape.

I have my lazyjacks led to blocks on the spreaders and back to the cockpit so I can get them out of the way when hoisting. They could be out of the way when the light air main is flying. The main would still be in the stack pack and out of the way.