Light wind sailboats

This may be a bit long winded, basically I want to know whatever I can about sailplans designed specifically for lighter wind ranges.

How do you make a boat that will sail very fast in very light winds?

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Where I live (Utah lake, Utah) there is usually not an abundance of wind. The wind usually does not go above 5 knots. If it does, it won't go above 10 without a storm. I'm looking for information on boats that are specifically designed to sail in light wind conditions.

I know there are several ways to handle it, First, just add more sails:



Second, you could customize existing sails to fly better in light wind, such as drifters and ghoster sails(very light weight genoas)

Third, you can just make the rig huge, like Reliance:



I'm thinking of what would be needed to make modifications to an already existing rig to extensively tune it for light air, including changing sailplan and adding boomsprits, longer boom, etc. The size of a boat would be a small cruisers/racer under 20 feet, possibly cats or some sort of stable monohull or tri.

If you just make the mast a lot taller, you increase weight, and you have to make it strong enough it can handle the occasional increase in wind as well, so Gaff rigs lend themselves well to huge sails on a short mast. Ideas?

 

Most designs are optimized for the general sailing expectations the initial SOR had in mind. If the design is a "spec" deal, then the sail plan will reflect what it's country finds acceptable, which is why you see proportionately less area in European models, compared to American of similar configuration and size.

There's also a desire to cover as much of a wind range as practical. A design optimized for light air, will have to reef early and might be over powered in modest wind strengths. A design that focused on heavy air, might need a healthy breeze, just to leave a dock, so the middle ground is picked, which offers modest light air capability, while still being able to handle SCA's without capsizing.

Simply put, a design can be optimized for light air work, but it'll suck when the wind picks up and naturally the reverse is true as well. Since most boats are designed for good sailing in 8 - 10 knots, you're pretty much screwed, unless you have multiple hoist options or the boat is a custom design, geared to light air. If you're looking for a design, check out multiple stick rigs, as they usually have more hoist options. I have a ketch, with a double headstay rig. I can fly 2 jibs, the main, the mizzen, a chute and a mule, so 6 sails at once, for serious light air effort. Of course, I rarely fly double headsails in light air, just a gennie or tall boy with the chute, so only 4 or 5 usually, depending on point of sail, but compared to a sloop . . .

 

I think what you are looking for is a light weight design. possibly a modern sports boat with a tall carbon rig. The key to having fun in light air is a large sail area high in the air, gennakers, code zeros etc all help.

 

Well, below is the answer the Thames sailors had before 1914....

http://www.yachtsandyachting.com/news/176600/Bourne-End-Week

 

Having grown up with light inland breezes, I think the key to good light air performance is an efficient sail plan (which means something slightly different to just a big sail plan). A nicely twisted roachy main, relatively flat and loosely sheeted will be more effective than a deep, tight-leeched pin-head. Rotating masts can be nice in establishing good flow over sails too. Have a look at NS14 rigs for an efficient light-air configuration of only modest area.

Efficiency over brute force is also good for when the breeze picks up and you don't want to have acres of sail all over the place.

 

That's quite a range of types. It might be a good idea to figure out what your other priorities are, so you can decide on the type of boat you want. Do you prefer monos or multis? Classic or modern? Etc, etc.

A Thames A Rater would certainly do the business, if it fits with your other needs. Some of the Norfolk Broads yachts would be very good too. Or you could go for an all-carbon tri (tris tend to do better in very light winds than cats, due to less wetted surface).

It comes down to what you want and what you can afford.

But yes, sail twist is very important in light airs.

 

Talking of Norfolk Broads This Is my sailing club a little while ago, and you can see the conditions we often sail in and the solutions at the time,

http://www.archivealive.org/video/index/id/121.

Today the latest solutions tend to be taller, thinner fore and aft maybe with a fat head Bermudan Main or small gaff, oh and a spinnaker.

Our problem is reaching over the tops of the trees to get wind which I guess is not the problem you have, we also have to be very manuoverable, the one day regatta shown above is now 7 days of up to 6 races per day, with everything from oppies to some of those actual sailing cruisers in the video maybe 180 boats in 1.5 miles of river.

As those above mentioned you need to narrow down your style ( and budget) of boat for the sailing you wish to do are you going to be single handed or with crew?
big many sailed rigs need crew, whereas a simple gaffer or Bermudan two sailed rig could be single handed.
Also how big are your waves? Something like the A Rater or Norfolk Punt is fine in smooth water, but waves more than a couple of feet would be rolling down the deck.

Something like this http://www.ykboats.co.uk/ is a good all round boat and does go fairly well in light winds (I'm in the pictures somewhere) we don't normally go out in more than 20Knots (but held our Nationals last year in 40!) There must be something like that available in the US .
Oh if you want something with a roof then boat like these would probably do, light displacement large sail area,
http://www.bluelightning.co.uk/index.html

 

One thing you can do is correct for altitude. Atmospheric density at 4500 feet is about 15% less than sea level. So you can add that amount of sail area without much concern. More than that and you need to look at the keel area because you need to increase the keel in proportion to sail once you have corrected for altitude. Other than that, you need to narrow you choice down a lot. Practical mods are model specific. Centerboarders are generally easier. Boats that don't look like they should sail fast are also easier.

 

I'd think a well designed tri would be a sure bet for light air. You can use a squarehead main and jib and a big asy. You can sail just on the main hull in the very light stuff but have reserve RM for stronger wind. The tri should have both amas clear of the water in no wind.
Good Luck!

Pictures,L to R- 1&2 Little wing and its bigger sister would be good in light air-esp the 20 footer, 3-Randy Smyths Scissor won the Everglades Challenge last time, I think, 4 &5
Mosquito, 20' :

 

I'll take the risk of making a reckless statement: On a dead run you can not go faster than the wind no matter how much sail you put up. In fact it is not likely that you could equal wind speed in light air. Larger and larger sail areas will increase the downwind speed incrementally in terms of small decimal differences but never equal to wind velocity.

To go faster you need more power. That means more wind. One way of finding that extra power is to use a kite. The kite can be 150 feet up in the air where there is very likely more wind. That seems overly complicated and just a bit clumsy on smaller bodies of water.

Having sufficient sail area is essential of course, but the boat itself is partly responsible for overall performance. A boat with minimum wetted surface will at least let you make the best use of whatever wind force is available. A boat of 20 feet or so will almost never approach its hull speed in 5 knots or less. Wave making is a factor but only a small factor at very low speeds. The ratio of displacement to sail area comes into play here. For example; a boat with 4 pounds of weight for each square foot of sail will respond to puffs much better than a boat with 5 or 6 pounds per foot square. Consider the simple principle of physics.....F= ma, or transposed, a=F/m. Light boats accelerate better.

Sail trim and attention to minor shifts is a critical matter in light airs. There is a subtle set of skills that separates the fast (comparatively fast) light air sailors from the slower ones. A study in concentration here, as well as a keenly developed seat of the pants feel. Be very still, don't rock the boat, pay close attention to fore and aft trim as well as the most favorable heel angle. A sort of chess game on the water.

I think that Doug is right about the tri but only if it is a light weight one. If I wanted a light air monohull performer for single handing, I might get an International 10 square meter canoe. They are light, narrow, and also blazingly fast when the wind pipes up. There are many others that would fill the bill. A Flying Dutchman maybe?

The real deal is to be satisfied with going slowly. You can almost achieve karma when the boat is moving smoothly, silently, and comfortably, even if it is slowly. Imagine yourself and your significant other sailing along on a brightly lit moonlight night....You are reciting Omar Khayam : "A loaf of bread, a jug of wine, and thou beside me in the wilderness, paradise enow"

If you are a young guy who has an uncontrollablly urgent need for speed then light air sailing might not be your cup of tea (or jug of wine).

 

Messabout, one of my great joys in the years I raced my Windmill was in an open regatta where it came down to me and a Flying Dutchman. Can you guess who won? Oh yeah-it was exceptionally light air though not dead flat.

 

Here is the kind of boat I would most likely be operating it on. The mast has been replaced and is a lot stronger now, and the amas will be next, they need to be a lot larger. I'm single handing it. She weighs about 100 pounds total, so not very heavy for the size of sail. I'm also making my own sails. I've discovered that the small jib, made from lightweight nylon, pulls much better than the main, especially in very light wind. The main just bobs around all over and the jib quietly pulls along. I've since put a heavier sail, about a 100% jib on. It works ok and pulls hard when the wind picks up, still more than the main. It's about the same as the small jib in very light air.

 

Which is why anyone interested in sailing fast downwind in light airs would not be sailing directly downwind. Check out the speeds 18 foot skiffs do on a broad reach in light airs.

 

Are both floats in the water at the same time?

If not, you already have probably the world's most efficient hull for light air.

The main might need more camber to it.

A lot of light air sailing success is based on technique.

I used to drive other sailors nuts with my cheap Super Snark(r). They'd be sitting around, bobbing, bitching about the wind, with their much better boat.

I would get tired of their complaining and just sail away.

Though the Super Snark had a generous sail plan, its Lateen sail was flat cut.

One of the tricks is to get your weight to leeward, so the sails will "sleep" on that side, just waiting to catch any Zephyr that comes along.

 

The bottom inch or so of each float is in the water. I've moved them up an inch each, because the tops have zippers on them so they leak water in rather quickly if I submarine the hulls. In zero wind with me sitting on one side, the opposite float is just barely out of the water.

Yes, the main was completely flat. I've since loose-footed it, and the power out of the main doubled instantly. However, the partial battens and loose footing exaggerate the creases you see here running from the clew to the head midway along the sail. I am thinking I'll either make the battens full length, convert an old Hobie 16 sail, make a new square top main for it, or convert it to a gaffer with a light nylon main. Thoughts? The helm is pretty much completely neutral right now, and I wouldn't mind a bit of weather helm.