Friday, June 26, 2009

Offwind Options

(This is an article we wrote for Multihulls Magazine two months ago. It's a good magazine, with some useful info.)

Watch out for the cliff! Every boat has it, every sailor feels it. Sailing upwind in 15 knots, the boat feels great, dancing across the waves. As you bear off onto a reach, the thrill increases as the boatspeed picks up and the waves feel softer. Heading down a bit more, you approach a beam reach, still reveling in the responsive feeling of power at the helm. Usually somewhere just below a beam reach, though, most boats, especially cruising multihulls, reach a performance cliff. Bearing off another 10 degrees causes the boatspeed to drop, swinging the apparent wind aft, slowing the boat further. While you were racing dolphins 15 or 20 degrees ago, now you’re watching jellyfish as the boat bobs along under main and jib, the collapsing wind over the deck has turned the heat up, and the evil engine key starts to beckon.

Modern multihulls led a design trend across the industry, moving sailplan power aft with larger mainsails and smaller jibs. Upwind, the jib completes the airfoil, shaping the flow over the leeward side of the mainsail and increasing its efficiency. But in terms of sheer driving force, the little jib, often less than half the area of the main, brings little to the aerodynamic party. As the boat bears away and the two sails begin to work independently, the jib sheet eases, the head twists out inefficiently to leeward, and little is left pulling the boat. Combined with (and a cause of) the apparent wind speed drop, this means the water gets stickier and the boat gets slower, quickly. At deeper angles when the main begins to blanket the jib, it becomes completely useless. What’s a speed hungry cat to do?

Fortunately, a range of sails plug the holes in the offwind inventory and allow you to leave the engine silent. Unfortunately, the broad diversity of shapes, materials, and deployment methods can be confusing to a guy just looking to come back from the Bahamas a little quicker. Choosing the right offwind sail depends on a variety of factors you must weigh do determine what’s best for the way you sail your boat.

Most sailors choose a sail based on the reality of how they will deploy and douse it underway, because if it’s too hard to use, it doesn’t matter how powerful it is. Three primary options exist across the range of sails: a temporary furler, a permanent furler, and a spinnaker dousing sleeve.

Temporary furlers consist of a drum with a continuous furling line at one end that connects to the tack of a sail, and an independent swivel at the head. Designed for use with a straight-luffed sail supported by a strong, low-stretch internal luff rope pulled tight, the system allows for a sail to be hoisted or left in place like a furling jib, then rolled out for use. When done, the sail rolls up, and can stay in place for a short time, or more often is lowered and removed, furler and all, into a sailbag. Recently, some companies have made temporary furlers designed for use with large, loose-luffed asymmetrical spinnakers, and while promising, these systems are less tested than those for rope-supported sails.

Usually only larger (50+ feet) with permanent bowsprits use permanent furlers, extending the attachment point forward of the permanent jib furler. These work just like your jib, rolling the sail around the extrusion and leaving it permanently in place with a UV suncover on the leech and foot. They’re the simplest, but most expensive to convert to.

Spinnaker dousing sleeves are the least expensive, but limited to lighter nylon sails. With these, the sail is stored in the sleeve in a sailbag below and brought on deck for use. The sock is hoisted and hangs with the spinnaker trapped inside. Standing on ahead of the mast, you pull the control line, the bottom of the sleeve rises, and deploys the sail.

Again, for many, the dousing system determines the sail. Some people want to leave a sail up and furled when not in use, and others don’t really care what they have to do as long as they get the most power possible. The convenience vs. performance tradeoff often is no compromise, but sometimes, the need for speed takes over.

Aerodynamically, headsails optimized for sailing close to the wind have straight luffs and relatively flat shapes – just look at your jib as the epitome of the upwind sail. Those designed to sail at the broadest angles look like parachutes, large, billowing spinnakers designed as large as possible to catch the wind. If you were to computer generate the animation from one to the other you would see the jib grow wider as the edges bulged out, and curvier as the middle got deeper. Sailmakers can design sails anywhere along this continuum, and advanced race programs might carry as many as 15 headsails, from the smallest jib to the largest spinnaker, with a wide variety of shapes in between designed for specific wind speeds and angles. Cruising sailors don’t have the need, crew resources, or budget for a highly specialized sail inventory, and as a result, four basic shapes dominate offwind sail design. Each of the shapes sails well in their intended usage range, but alas, no shape does everything well. Please note, terminology varies for many of these sails, and it’s more important to understand the shape and function than remember a specific word that different sailors might apply to different sails.

For close-to-the-wind sailing in light air, a large genoa look-alike often called a Screecher is preferred. A triangular sail about twice to three times the size of a cruising cat jib, the sail, positioned on a bowsprit in front of the jib, provides close and beam-reaching ability, while still serving adequately as a broad reaching sail in medium to heavier breezes. Set with a temporary or permanent furler, the target wind speeds and angles intended for the sail shape the choice of the sailcloth used, usually Dacron on a tropical cruising cat, but light laminates and heavy nylons are also possible.

Growing a bit curvier, a Code Zero-style sail sacrifices a little pointing angle to provide more power in the wide angle range around a beam reach. Still on a centerline bowsprit, with a larger roach and deeper profile, the sail drives a heavy cat more effectively than a screecher, but can’t get quite as close to the breeze, and still suffers from getting blanketed by the main at broad angles. Because it’s not used as close to the wind, sailcloth can be lighter, usually spinnaker Nylon, making it more efficient in lighter winds.

Even larger and rounder, an asymmetrical cruising spinnaker abandons the tight luff rope of the previous two sails for a large, positively-curved luff designed. Flown most often off the weather hull (or on the centerline when closer to the wind), the sail’s large, balloon-like three-dimensional shape is designed to float it out to windward, rotating out from behind the wind shadow of the mainsail. This makes this light nylon sail very effective from beam reaching angles in light air all the way through a broad reach.

Finally, a traditional symmetrical spinnaker offers great downwind power and ease of use when broad reaching and running. Usually trimmed with dual sheets and guys to facilitate gybing on long, wind-aft passages, it’s the most powerful and autopilot-friendly way to go dead downwind.

Sailors committed to longer-range cruising, looking to cover the entire wind range from close reaching through running, find a benefit in two of these sails, choosing one of the reachers (Screecher / Code Zero) based on their desire to leave it furler or remove it, and one of the spinnakers (Asymmetrical / Symmetrical) based on how much actual dead-down running they think they’ll be doing. Most sailors, though, are looking for just one to serve the majority of their offwind needs. The decision should be based on any predictable sailing plans for the boat, any preference for setting and dousing options, and desire for power.

South Florida sailors who make frequent summer trips back and forth to the Bahamas will use their main and jibs upwind, and then need one of the spinnakers, likely an asymmetrical, to speed the downwind passage home. Blue water sailors who spend considerable time reaching often choose the “set it and forget it” ease of a reaching sail, and choose between them by deciding whether they want to remove them after use or leave them hoisted furled for short periods of time. Those seeking the most convenience choose a Dacron screecher with a suncover that can be left furled in place for periods of time (though still removed when the boat is unattended). Or, if you want a bit more power – and color – in your sail and don’t mind putting it away when done, the Code Zero may be your choice. When you understand the tradeoffs in convenience and power, and the usage ranges associated with each sail, viewed in the context of how you sail your boat, the right choice becomes clear, and the temptation to fire up the engine on those light-air reaches drifts away with the jellyfish behind you.

Thursday, June 18, 2009

Quick & Dirty Navigation

Sometimes sitting around the office dreaming of a trip you may find yourself (gasp) without your charts or navigation software. For a quick read on distance between any two points, turn to -- you guessed it -- Google Maps. A cool and probably not so new feature can be found in the My Maps section. It's a checkbox that allows you to click in two locations on the map to the right and get the distance between them. Set it to Nautical Miles (as opposed to some of the other goofy units they have there) and suddenly you can begin planning your next passage. 975 nautical miles from Fort Lauderdale to the BVIs. I know there are chart overlays somewhere -- anyone have a link?

Thursday, June 11, 2009

Coach Clinic De-Brief

Sorry for the delay on this, but folks were out sick during a busy time and I was running around a bit keeping up. But here is the Powerpoint presentation we used at the coach clinic debrief on Monday, June 8 in the loft. People who attended can review the info at a more leisurely pace, and those who didn't can get a glimpse. It's a 13 mb file, so give it a little bit.

Debrief Presentation Here

In the next few days we'll have video of the full presentation shot by Tim Leonard. We'll track the "comments" section below in case anyone has more questions about the topics we covered. The easiest way to know when they get posted is to click the "Follow" button above (if you're logged in as a Google user). Thanks to all who came.

Tuesday, June 2, 2009

We're a bit late posting, but congratulations to the Boston College Eagles who won the 2009 Intercollegiate Sailing Association National Team Race Championships. Super constructed the colored jibs for the event for Hood San Francisco. This is the equivalent of the NCAA football championships, and we're happy to have played a part.

Monday, June 1, 2009

SummerWind Sailing Debut

The 100' Alden schooner "SummerWind" with her Doyle inventory made her sailing debut with a quick jaunt to Bimini with the owner and family this weekend. Here she is waiting upon return to Ft. Lauderdale. We hope to have shots of her sailing to share, and expect them to be even more beautiful.

HISC Coach Clinic

It was a very "diverse" day on the water yesterday, with everything from zero to 18 knots, and breezes from the southwest and east -- often simultaneously! We're taking the photos, video, notes, and later thoughts we collected throughout the day and consolidating them into a...

MONDAY, JUNE 8 -- 6:00 p.m. to 7:30 p.m.

Super Sailmakers
4710-C NW 15th Avenue
Ft. Lauderdale, FL 33309

Please e-mail us here to let us know you are coming so we can shop and plan properly (we'd hate to end up with too much beer).

Refreshements will be served while we review photos and discuss ways to improve boat speed, boat handling, and racecourse planning. With questions, contact us at 954-763-6621. See you then!