Mutihull Primer - Faster is Funner
Jim Antrim, 12/1/92, published in LATITUDE 38, Feb 93

There are so few avenues these days for having a really good time: Sweets rot your teeth, drugs rot your mind, even beer makes you fat. You can't go for a walk in the woods without making reservations, obtaining a permit, filing an environmental impact statement, and catching Poison Oak. Even if you can find a road that doesn't have a traffic jam on it, you can't drive your car fast without worrying about air pollution and polite men in unfriendly costumes. Sex requires a formal contract, numerous advance medical tests, and a secure latex seal. And in our own sport, not a single overnight race is left in the San Francisco ocean, where men used to eat nails for breakfast and come home smelling bad; but now earn their toughness vicariously by wearing fluffy clothes with rugged names like Patagonia. "I'm not sure where it is, Martha; but I bet a hard and lean fellah went there once in clothes much like I'm wearing now."
Well I'm here to tell you about my own solution to the middle age crisis. You can clear more cobwebs from your head in one half hour windy multihull reach than you can grow in a whole tax season. Admittedly, 20-25 knots is no faster than an average guy in tight black pants on a Sunday afternoon bicycle ride. Yet, the sea does have a way of quadrupling the sensation of speed. Perhaps if the guy was riding his ten speed down the rock slide on the side of Mt. Shasta. That's the sort of thrill level we're talking about. Hopefully, the margin of safety is better. So the point here is, I'm recommending you try it. It's not as tough as it sounds. Heck, even girls can do it. Assuming, of course, they eat nails for breakfast.

I'm presupposing here that you are coming, as I did, from a background in monohull sailing. You know the basics; you weaseled yourself a crew position on a multihull; you just don't want to get out there in your Patagonia and commit a faux pas [French dog breeding term - literally: four fathers].

So what's different about multihulls? First, a few basic premises:

Consider everything you know about apparent wind, and what a good thing it is. Multiply by twenty. Forget the notion that multihulls do not go upwind. Modern multis go upwind like a freight train. Do not forget the notion that multihulls are fast on a reach. See item 1. Multihulls gain their speed advantage due to high transverse stability (righting moment). That means they are difficult to tip over sideways. Anytime on your monohull you wish you had one more fat body on the rail, the multihull will be faster. When a multihull is not using its stability, say light air upwind or dead running in almost any wind, it has lost its primary speed advantage. Most of the unfamiliarity you will experience at first is a result of higher speed. This can be disorienting to the degree that even a vastly experienced sailor may have a difficult time telling where the true wind is coming from.

Let's consider a 8-14 knot wind range. A typical range in much of the world. Smooth delight. Warm water. Dolphins leaping at your side.

You're going upwind. You find that you are able to point as high as the monohulls nearby. Cool! I thought these things couldn't point. The dork sailing the sistership is pointing 5 degrees lower, and reaching toward Never Never Land. He tacks and comes back and is 10 lengths in front of you! What happened? He read Premises 1 - 3. By footing a bit he picked up 4 knots of speed, his apparent wind increased, and he ended up at a better windward VMG. The tippier monohulls may be at the top end of their #1; but you've got stability (power) to spare. Forget the feathering; and ignore that voice in your head that can't stand pointing lower than everyone else. Foot the thing. You want power - shovel some coals in the oven. Drive it hard, with your sails at max lift coefficient (leech tales thinking about stall). A slow snake wake to weather often works well in these conditions: you find that you can bring it down a bit, build up some speed and apparent wind, then creep back up carrying the apparent. Your hand is very smooth on the tiller. Your grin stretches back toward your ears.

Now you're around the weather mark; and the next mark is almost dead to leeward. The monohulls have their pole way back and are sliding straight toward the mark. The ex-dork has his pole to the headstay; and is headed for Never Never Land again. What the hell, we can all use a sprinkling of fairy dust now and then; you decide to follow him. Man! The chute is full and in pretty tight; you're zippin' along. Then a little puff hits and the boat lights off. Your cheeks are cramping up around your grin. With the speed burst, your apparent wind angle jumps forward. Trim! Trim! But it's no good. Joe was winding the spinnaker winch like a man possessed; but the spinnaker still collapsed. Ex-dork is sailing 10 degrees lower and has gained another 5 lengths. The problem? You remembered apparent wind; but forgot to multiply by twenty. You simply can't react fast enough with the spinnaker sheet, the boat just accelerates too fast. The helmsman must react to the wind changes, bearing off with a puff to keep the apparent wind angle constant, letting the puff carry you down toward the mark. And forget that monohull tendency to dump the traveller and mainsheet. You've got stability, remember? Keep the traveler up, so the main is still at full power. Your leech tales stall for a second on every other wave. Again you may find that a slow snake wake is fast. Remember Premise 2. The reach is your strong suit, so now you want to bring it up a bit, 5build up some apparent, then see if you can ease it back down carrying the apparent wind and speed.

So what have we learned about moderate air conditions? Always err toward the reach. Upwind optimums will be at lower true wind angles than you are used too. Downwind optimum jibe angles much higher than you are used too. Apparent wind angles vary through a much tighter range, and should seldom be aft of the beam. Even hard guys, such as yourself, don't mind heeling half as much and sailing twice as fast.

O.K., let's try a light air race. Light air is the time for finesse, gentle movements, patience. Frankly, light air is the time for ULDB monohulls; but that's not what we're talking about on the show here today. While you're sitting there, being patient, you begin to realize that "multihulls" is short for multiple hulls. The darn things have 2 or 3 hulls in the water! More hulls mean more wetted surface! More hulls mean that you're busy watching the starboard bow, and a wave comes up under the port bow and throws the wind out of the sails. You shift your crew to leeward to get some shape in the sails but the boat only heels 2 degrees! Man, I wish these things would heel more! We're going to quit the bellyaching now; and figure out how to sail the boat. You begin to notice that with the weight to leeward, the boat is much steadier in the water, the sails are not slatting around. O.K., let's try the old monohull technique of weight forward. You call for it, and the crew settles around the forward crossbeam on the leeward hull. Yeah! Less burble at the transom, seems like less wetted surface. You've picked up a bit of speed.

In light air the first priority is to steady things out; second is to minimize drag. If you have a trimaran, minimum wetted surface will be with the boat balanced on the main hull, amas clear of the water. However, this only works in flat seas; and you know as well as I that truly flat seas are every bit as common as a total solar eclipse. It's better to be leaning steadily on one hull than slapping from port to starboard ama. On a catamaran, heeling the boat will reduce wetted surface. I have even used a trapeze off the leeward bow.

Multihulls enjoy other, less obvious, light air advantages. These days, most multihulls today have a fully battened main. These are great for holding the sail steady. Anyone who has slatted about for more than 5 minutes can appreciate the enormous speed (not to mention sanity enhancing) advantage of this feature. And, if I may be permitted a bit of promotion, wing masts and boomless mains are great in these conditions. The wing mast is efficient: low drag and smooth flow over the main. A boom in light air is like hanging a 3 pound salmon ball on your spinnaker clew. All it does is make the leech too tight and fling the sail about.

Spinnaker time? How often on a tight spinnaker reach have you wished you could move the sheet lead 2-3 feet to leeward? On a recent, very light air spinnaker reach back from Half Moon Bay we blew the monohulls away, largely due to a nice wide trimming base. The key is to get the main and spinnaker to interact, not stifle each other.

Symmetric vs. Asymmetric? Let me predict right here that in the not too distant future we will view symmetric spinnakers as a bit of quaint nostalgia, like square rigs and cotton sails. Multihulls, along with Aussie 18s, Ultimate 30s, International 14s and the like, have led the heavier monohulls in the movement toward asymmetric spinnakers. Why? Premise 1. If the wind is always forward of the beam, why would you ever want a symmetric spinnaker? Jibing an asymmetric chute takes a bit of practise; but is generally easier and requires fewer people than a symmetric chute.

Ready for a heavy air sail? This is the reward, the holy Grail. You've raised your sails in the harbor in the lee of the hills and are headed out to the Bay, with its familiar dull green/brown color. Fingers of fog are slipping over the top of the Sausalito hills. Here comes the first puff. You are standing to look around, your monohull instincts preparing you for the boat to heel with the puff, then gradually build up speed. But as the puff hits, the boat has other ideas. It can't heel , what to do with all that energy? Why not convert it directly into forward motion? RAWWWR! It takes off from under your feet with astonishing acceleration and you stumble aft trying to catch your balance. Wow! What's the fun meter say? 21.4 knots? The motion is smooth, it doesn't feel quite that fast, until you notice the shoreline zipping by.

You approach the start line where lots of boats are milling about; and you want to join the crowd, check the line, look at the current on the buoy, yell at some old friends. However, more multihull truths are becoming evident. First, it is difficult to "mill about" in these conditions. The only really controlled way to go slow is to head downwind with your sails overtrimmed. Second, a very fast boat is a big responsibility. You can't be quite as aggressive with your right of way rules. Starboard tack is nice; but you've got to cut the other guy some slack; he often doesn't have time to respond. Third, and most important, the other guy is not used to looking for zippy little boats. He's used to guaging a cross or dip on about a 45 degree line. He may not even notice the guy 70 degrees off his bow and half a mile away.

Finally the gun sounds and you're off like a rocket. Look at this! We're doing 12 knots upwind! You've been in the boat long enough now to have the boat speed thing in hand. The dork is outside near the pin end, and the tide is flooding. You smile to yourself - finally a chance to play your trump card. All those years in monohulls have taught you one thing about multihull sailors. When it comes to tactics, they're like the blown out jib: they haven't a clue. You're working your way up the shore, past the I beam, around Anita Rock, in to the beach. Dork head has tacked out into the flood. Idiot! Maybe a little El Toro racing would teach you some tricks! Bit better breeze out there, but the flood is a good two knots stronger. You're feeling pretty good in the puffs, lifting up the beach. Yet in the lulls, your permanent multihull grin begins to melt. He's skunked you again. Why? In the steadier, stronger breeze he was doing 15 knots to weather, a 3 knot gain, unheard of in monohulls. Enough to overcome the current. Sigh! Another lesson learned the hard way. In the multihull, tactical priorities shift from current over wind to wind over current.

Now you're out in the ocean waves past Pt. Bonita, and coming up on the monohulls that started 40 minutes in front of you. The waves are travelling at 16 knots toward the shore, and you're doing the same speed in the opposite direction. The boat is leaping off the top of the waves. A few good slams send the message to your brain - its snake wake time; but for a different reason. Just like the monohull, you head up on the face of the wave, then bear off down the back, keeping the leeward hull in the water. As you gain confidence, you foot a bit, pouring on the power, and the motion smooths out still more. You discover that by keeping wind pressure on the sails, the weather hull stays well clear of the waves, and when the main hull bow leaps out of a wave, you can ease it down again, controlling the sail pressure with small movements of the helm.

Sailing a multihull in heavy air demands that you are tuned into the boat. The trick is in finding the limits of how far you should "power up". For example, a monohull has exceeded its limits when the lifelines are dragging in the water, or when you have a big wave boiling off the trailing edge of the keel. You are overpowered because the extra drag caused by these factors has exceeded the extra drive you've gotten from the sails. Depending on the design, a multihull may begin burying its leeward bow, dragging crossbeams or struts in the wavetops, or stalling the rudder. Full racing boats reach maximum speed potential when the weather hull of a catamaran, or the main hull of a trimaran come out of the water. Each boat has different limit indicators. Some of them are safety, as well as speed limiters.

In what seems an amazingly short time you are closing on the Light Bucket. Never has the upwind half been so thrilling, can that wonderful broad reach in live up to expectations? Your spinnaker is hooked up; but you want to wait on it a bit, talk through the set on this still unfamiliar asymmetric kite, get the feel of the boat in the waves. You round the mark and are surprised to see the speed drop from 16 to 9 knots. It feels like you're barely moving. The boat feels (how to say it?), serene? That's no good, we're not here to chant our mantra, this is a race! The chute goes up. (That was pretty simple.) You head up a touch to get wind to the luff, and the boat comes to life. Whoa, baby! With the extra sail area and a few degrees more point it's Premise 1 in action again!

You soon find that you are actually overtaking the waves, not riding them. The helm technique shifts from trying to get the most push from the waves to how to best steer past the damn things so they don't slow you down. Then you come ripping down the face of one big wave and sail the leeward bow down into the back of the one in front. Now there's a different experience. Now you've got three bows to watch instead of one. O.K., maybe we're pushing it a bit too hard. How to slow down a bit? You think back to the mark rounding, think back on Premise 1 and decide to reverse it. You head 5 degrees deeper downwind and the speed comes back to subsonic, the boat feels more controlled.

Heavy air can be dangerous in any boat. You've got to know the beast you're riding. One universal truth about multihulls is that their wide hull platform adds only to sideways stability; not to longitudinal stability. They are difficult to tip over sideways; but no better than a monohull, sometimes worse, in the fore and aft direction. In terms of understanding heavy air wipe outs, this is the primary control difference between the monohull and the multihull. A broach in the monohull sense is unheard of. Multihulls rarely capsize; instead they pitchpole, or "capsize" diagonally. This is usually the result of a leeward bow stuff. Like a broach, this happens when you're pushing hard in a racing scenario. One can always back off and sail in great safety.

You're jibing toward under the Gate, hot on Dork Head's heels. The South Tower Demon throws a puff at you, and though you're already doing 18 knots, the acceleration pulls at you, and you scream up on DH in an exhilarating rush. You rip across the line side by side. While you may not be the best sailor on the water today, there is some satisfaction in knowing that the best sailor is still out there, out of sight behind your transom.