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the Ultimate 20 asymmetric spinnaker forum

Sport Boats and Asymmetrics

by Ed Adams

"Sportboat" was the invention of a clever magazine editor, who was searching for a catchy phase to describe a new genre of sailboat — small, light, and fast. This new breed, as he saw it, would give us uncomplicated, uncompromised racing, unabashedly fearless of the handicappers.

Boats like the Ultimate 20 are catching on simply because they are so much fun to sail. That fun comes from both the cloud of canvas that they spread and the challenge of learning how to tame it. To race one of these boats is a snap. To win, however, will require you to learn some new spinnaker techniques.

The earliest sportboats were equipped with conventional spinnaker poles and symmetrical sails because PHRF didn't allow asymmetrics. That has changed. PHRF fleets have legalized asymmetric spinnakers for sportboats like the Ultimate 20 that are equipped with bowsprits.

Trimming the asymmetric

Asymmetric spinnakers have long luffs, short leeches and a draft forward, open-leech shape. As long as the apparent wind and the pole are well forward, an asymmetric is always faster than a symmetrical spinnaker.

In light air, the apparent wind is always forward when sailing downwind. In these conditions you would typically jibe through 90 degrees. Pointing the boat dead downwind is plain slow.

As the breeze builds all boats can sail lower angles as pressure on the spinnaker builds. With a sportboat, however, you cannot square the pole aft as you would with a conventional spinnaker. This means that you are limited as to how "deep," or directly downwind, you can sail. When racing in PHRF, the only condition in which a sportboat has trouble saving her time is running in 10-15 knot winds.

There are a number of things you can do to encourage your asymmetrical spinnaker to "project" its luff to weather in these conditions. First, ask your sailmaker to make your sail fuller, especially in the head, and with a minimum length leech and a maximum length luff.

With a short leech you can ease the sheet without over twisting the sail. Too much twist causes the head to collapse prematurely.

When you have a longer luff, the sail will fly further away from the boat so as you ease the sheet the luff will have more of a natural tendency to rotate to weather. Easing the halyard and tack line 6" each also encourages this luff projection.

However, as you fly the luff farther from the boat, it also becomes flatter and more unstable. That is why you want to choose a sail that is designed to be fuller.

As a trimmer, what you are looking for is a 5"-10" curl in the luff as you ease the sheet. If the curl is too large, the whole sail can collapse before you are able to trim the curl out. If this happens, tighten the halyard and tack line. This will make the luff of the sail fuller, more draft-forward, and less critical to trim.

You don’t trim an asymmetric chute like a symmetrical one. You fly it by the telltales on the luff, like a jib. In light to moderate air, the goal is to sail the boat as low as possible without the sail collapsing behind the blanket of the mainsail. A common mistake for a new helmsman is to head down when the chute collapses. The sail usually collapses because the mainsail is blanketing it; you have to head up to fill it.

The trimmer must constantly talk to the helmsman about the pressure on his sheet. As soon as the pressure softens, he must tell the helmsman to head up slightly until the sail is repressurized.

As the wind builds, there will come a point when, if you head up instead of down in a puff, the boat will start to plane. The apparent wind shifts forward with the added speed, and the asymmetric chute comes into its own again.

Once planing, sail as low as you can. But don’t let the boat drop off the plane. Your VMG (velocity made good) downwind is always better with the increased speed, even if you have to sail slightly higher to get it.

In planing and surfing conditions, a sportboat can accelerate so fast that your feet come out from under you. No winch can keep up with the almost instantaneous changes in the apparent wind. The trimmer has to sit down and trim the sail by hand; sometimes with two crew on the sheet in blast reaching conditions. The rest of the crew has to scrimmage the full length of the cockpit, using all the kinetics the rules allow to surf waves.

Pumping the sheet of so large a sail is sometimes out of the question. But you can pump the sail with vigorous steering. The spinnaker is so far in front of the boat when hung from a bowsprit, that by simply pumping the tiller you also pump the sail.

Handling techniques

Handling the spinnaker is no more than a two man job, but those two had better know what they are doing. Setting is simple; jibing can be another story.

The big decision when jibing is whether to run the sheets inside or outside of the luff. Jibing inside the luff reduces the amount of new sheet to be hauled in, but there’s still a handful. One crew should assist the trimmer by pulling on the new sheet in front of the turning blocks.

On inside jibes the sail is jibed like a jib, with the clew pulled across the forestay inside of the spinnaker’s luff. For this type of jibe, the easing of the old sheet is critical.

If you overease the sheet, the clew goes past the luff. Underease it and the clew fouls on the headstay. Having marks on the sheets makes it easier, as does adding a pennant to the clew of the sail. On a boat like the Ultimate 20, having the crew roll the boat to weather just after the jibe hastens refilling.

Leading the sheets inside the luff is the preferred method in light to moderate air. In moderate to heavy air, it’s best to lead the sheets outside. Then, as the boat is jibed, the entire sail floats harmlessly in front of the boat. The drawback is that it takes slightly longer for the sail to refill.

No matter what the jibing method, an asymmetric always collapses when jibed. Therefore, you would expect it to be at a disadvantage to a boat equipped with a symmetrical spinnaker. However, the asymmetric’s draft-forward shape allows the sail to accelerate out of the jibe faster, so the net effect is a wash.

To refill an asymmetric after a jibe requires the boat to come out of the maneuver "hotter" than she went into it. After the sail refills, the trick is not to bear off until the boatspeed begins to rise.

The only real crew work disasters in sportboat racing come at the leeward mark. Because an asymmetric has such a long luff, the foot of the sail is lapping at the water as the boat heels. This means that if the halyard is released while the sail is still "pressurized", the sail will always end up in the water.

Early sportboat regattas were comical at the leeward marks, as boat after boat found themselves parked with sea anchors after an attempted douse. After much experimentation, a hierarchy of preferred methods has been learned.

The best way to douse an asymmetric is to jibe into it. Make a last minute jibe while approaching the leeward mark and leave the sheet cleated so the sail lays against the weather side of the rig. Then the halyard is released and the sail falls on deck.

When there is not enough space for a last minute jibe it seems best to approach the mark from a few boatlengths above layline. Then the boat is run off so the sail collapses behind the mainsail. Without pressure, the tack line can be released and the sail pulled into the companionway. Or the clew can be hauled around to weather and then the halyard released, if that is the side from which you plan to set it later in the race. Either way, make sure the clew is in the crew's hands before the halyard is uncleared.

Let's say you are approaching the mark on or below the layline, and you don't want to run off to blanket the sail. In this case, you can try a risky maneuver. Release the tack line and let the tack of the chute blow out to leeward. But the tack line must be very long and carefully flaked. If it fouls, or if the crew can't hold onto the clew of the sail, both the sail and the boat will end up out of control.

Racing one of these new pocket rockets is a challenge, to say the least. But there is no better way to broaden your sailing horizons than to learn a new trick or two.


the Ultimate 20 asymmetric spinnaker forum
Twisting in the Wind

by Dick Martin

Way, way back when I used to race in dinghies with bendy masts, the last thing I ever thought about was mainsail twist. As a matter of fact, I’ll bet that none of the dozens of books I used to study in those days gave twist more than passing mention, and then only to stress how important the recently invented boom vang was for preventing excessive twist off the wind. Going to weather in strong winds, in order to flatten the main I would crank the vang tight enough to bend the lower part of the mast, and maintain lots of mainsheet tension to pull down on the leech and bend the upper mast. I’d drop the traveler to leeward when overpowered, and ease the mainsheet only as a last resort, blaming myself and my crew for not hiking hard enough whenever I had to ‘wimp out’ that way. That technique seemed to work fairly well way back then. Although the U20 has no backstay and in many other ways acts like a big planing dinghy, its mast and mainsail, I have finally realized, are different.

I started out trimming the U20 main my old way in the 8-20 knot winds that are common this time of year on the lake in the Ouachita mountains that is home to BigBird. But when I would ease the traveler in strong gusts, the boat would continue to heel and carry heavy weather helm until the traveler was all the way to leeward. Trimmed that way the boat would wallow and wouldn’t point worth a darn, and the fully battened portion of the main would flog so hard it would shake the whole boat as the full-length battens snapped violently back and forth from concave to convex. I’m a slow learner (old age seems to have made me stubborn, too). Rather than trying to reef in the middle of a windward leg in conditions like that, twice I dropped out of PHRF races, much to the glee of the crews of the heavy old conventional keelboats that made up the bulk of the fleet.

It wasn’t until I had been sailing my U20 for over a year, single-handing for fun on days when the wind would build until it was too strong for one body on the rail, that I began to experiment with other ways to depower the U20’s main. My problem, I finally realized, must be the huge roach and all that extra sail area and power up high in the sail plan. My old technique made the leech way too tight. When I attached some telltales to the ends of the full-length battens I found that, sure enough, when the main was overpowered the whole upper leech was stalled and would remain so even when the traveler got near its leeward limit. Excessive heeling and weather helm are a whole lot worse than a little too much fullness in the main, so I decided to forget about trying to adjust mast bend with mainsheet and vang tension. What a revelation! With the vang slack I found I could beat with the traveler all the way to windward, keep the boom near the midline in wind velocities which, with a tight vang and/or lots of downward mainsheet tension would have required dropping the traveler well to leeward, and keep BigBird on his feet and moving at around 5 knots with a pointing angle of 40 degrees or better. Easing the mainsheet in the gusts would cause only a little backwind in the lower main, and I could keep the ‘Bird driving even then.

It now makes embarrassingly obvious sense to me that the U20 should be extra sensitive to mainsail twist. Not only is the main the prime source of power, and the roach huge. The narrow, very high aspect-ratio keel makes it essential to keep the boat upright and moving fast to generate lift and minimize sideslipping—which, incidentally, makes it unwise to rely on feathering as a means of dealing with gusts. There is a surprisingly large wind velocity gradient between the foot and the head of any sail, particularly the high aspect-ratio U20 main. Up in the full-battened zone the higher velocity makes the apparent wind angle substantially larger. I have been amazed at how far I can let the main twist in more than 12 knots of wind before the upper sail shows any signs of luffing, and how strikingly different are the angles of attack of the upper and lower leech areas when their telltales are all flying nicely.

I have also discovered that, with the vang slack and the traveler trimmed to weather, tiny adjustments of mainsheet trim—as little as three inches, which must allow the end of the boom to rise no more than a millimeter or two, and twist to increase by only a few milliseconds of apparent wind angle—make a difference in heeling force and weather helm. I now have marks every three inches on the mainsheet where it passes through the cockpit-floor cam cleat, to help me fine-tune mainsail trim to windward. When weather helm increases I simply ease the sheet three inches at a time, particularly if any of the upper leech telltales have stalled, until things feel right and the telltales are flying again. And vice versa: when the helm begins to feel mushy I trim back in a little until it feels good again (unfortunately the leech telltales don’t help you know if you have too much twist; unlike windward luff telltales they will continue to fly even when the sail is flat out luffing).

Reminiscing over pictures of the 1996 Nationals one day, I realized that on the windward legs late in the day when the ‘hurricane’ had arrived in the Gulch, BigBird usually was standing up nicely when many of the other boats were heeling excessively. At 535 pounds, the ‘Bird’s crew must have been among the lighter ones in L.A. Yet only rarely did I set the traveler more than an inch or two from its windward limit. In 20 plus knots I was too busy at the time to notice how other boats were trimmed, and the pictures don’t show that very well, but I suspect that a difference in mainsail trim deserves the credit for BigBird’s apparent slight edge in windward speed and pointing ability.

If you haven’t done so already, the next time it blows put some telltales on your leech, mark up your mainsheet, ease your vang, keep your traveler up to windward and give this technique a try. You may find that you and your U20 also enjoy ‘twisting in the wind.’

Tips on Tipping Over
(here's some real tips!)

In the winter of 1966-67 during local PHRF races, in 12-22 knot gusty winds and 30-60 degree shifts, my crew and I had several opportunities to practice the fine art of broaching. I think we learned a few things, some of which are obvious, including some things that may help you when you encounter similar conditions (hopefully not in the 40 degree air and water temperatures like we had on one occasion).

The most reassuring tip I have for you is that the U20 handles a broach with remarkable aplomb. Those 450 pounds on the end of her long keel bring her back up amazingly quickly, regardless of how the broach occurred. And, counting our experiences during practice races in Hurricane Gulch, I think we have tried all the ways it is possible to broach, while flying a spinnaker at least: (1) catching a sudden lifting gust on a reach with the spinnaker sheet cleated (my favorite, because I can blame my crew); (2) failing to ease the mainsheet enough when bearing off around the windward mark and getting hit by a huge gust while attention is focused on getting the chute up (which causes the boat to heel and generate too much weather helm for the rudder to handle without cavitating); (3) making the mistake of 'heating up' immediately after a jibe in wind that is too strong for that maneuver; (4) catching a gust in the middle of an ill-timed jibe: and, (5) on a reach, reacting to a hard gust by letting the boat round up instead of bearing off as she starts to heel.

When conditions warrant, tell your crew that a broach may be unavoidable, and when it starts calmly announce, "OK, hang on, we're going over," when it happens. If you are prepared, it's amazing how easy it is to keep your cool. Just get a good hold on the windward lifeline, transfer your footing from the floor of the cockpit to its leeward side, imagine the roostertail being generated by the leeward spreader tip, and calmly wait for the boat to pop back up—which it will do before you know it.

Then the challenge begins: keeping it from happening all over again as soon as she rights herself. Your role is to get the hull under the mast immediately. Before weather helm overpowers you again, bear off. To do that the mainsheet has to be eased completely. Your crew should try to set the spinnaker sheet for a broad reach as the boat is righting itself. The chute will help you bear off, and get you moving again—remember, speed downwind is now your ally, because it reduces the apparent wind velocity. And if you broached because of a sudden squall, or getting going again carried you too far to leeward to fly the spinnaker for the rest of the leg, you'll need that speed to calm the wind and get the chute down. But if you can keep the chute up you can get back up on a plane in an instant and go flying right back through the lee of that big lumbering conventional boat that snickeringly snuck by you while you were inspecting your keel.

Here are some tips on dealing with tips. More or less in order of importance.

1. Hang on to the windward lifeline. If that fails, grab the leeward one while you are tumbling down toward the water. Rescuing a skipper who has fallen out is an almost impossible task for your two remaining crew members who are confronted with the challenging task of dousing the chute first, before they can even begin to think about retrieving you.

2. Hang on to the tiller at all costs (only exception: see tip #1). Even though the rudder has cavitated or is out of the water, you're going to need it again—real soon. And if you let go, weather helm will put the tiller in the worst possible place to retrieve it from, all the way to leeward. And if your luck is like mine the tiller extension will get hung up in a stanchion or lifeline while it's out of your hands. And it is unlikely you can retrieve the tiller and regain control before you go over again.

3. Train your crew member who handles the traveller to hang on to something with one hand and uncleat the mainsheet and let it run free as the boat comes back up. Both of your hands are already fully occupied with the lifeline and the tiller. If the main fills on a reach you'll be overwhelmed by weather helm and will immediately broach again.

4. Try to keep the chute under control. It may be tempting to let the sheet go. But you will need the chute to counteract the mainsail and help you turn downwind to get the boat on her feet again.

5. When you gibe in a strong wind, as soon as the boom comes across veer—hard—to leeward, to overcome the inertia of the mast which will cause excessive heeling, and avoid the resultant weather helm that will overwhelm you if you turn too far in the process of jibing (this old planing dinghy technique works exactly the same way in a U20).

6. Never risk broaching near a leeward shore or a leeward boat. You need plenty of room to leeward to recover. If there is any chance of broaching near leeward obstructions douse the chute before you run short of room, or don't set it in the first place.

7. This is the most important tip (make that read absolute rule) of all. If it is cold or if you think there is any chance of broaching, require everyone on board to wear a PFD. And if you don't already have them, install lifelines on your boat. If we had not had them this winter, almost certainly at least one of us would have taken a very cold bath. And a crew member who dies of hypothermia is every bit as dead as one who drowns.


A perfect   Mexican takedown

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