BOATSPEED

The chal­lenge of rac­ing in large ocean swells is pro­nounced in smaller boats, where the trick to stay­ing fast is to an­tic­i­pate weight and sail-trim ad­just­ments.

Sailing World - - Contents -

Mike Ing­ham found him­self rac­ing in big swells, re­quir­ing a dif­fer­ent ap­proach to his sail trim.

At the This­tle Mid­win­ters West, sailed in the Pa­cific Ocean, off of San Diego, each morn­ing, surfers were ea­gerly launch­ing off of nearby Sun­set Cliffs. Surf’s up! It was great for them, but chal­leng­ing for us. We sailed two days of clinic, then raced three days, all in sig­nif­i­cant Pa­cific Ocean swells, which gave us five days to fig­ure it out, and as a re­sult, we learned some valu­able lessons.

Though not moun­tains, they were large, fast-mov­ing hills. In the troughs we could only see the top half of another boat’s sails, and there was no hope of spot­ting a mark un­less we were both on a crest. Go­ing fast in these rollers was fur­ther com­pli­cated by their di­rec­tion. On port tack, they came from the wind­ward side. On star­board, we sailed di­rectly into them. If that wasn’t enough, much of the re­gatta was in 7 knots of wind — not quite enough to power through the rollers.

Star­board tack was like a roller coaster, with the waves com­ing straight on to the bow. Climb­ing the hill was slow. It felt as if we were inch­ing along, like the roller-coaster

car was be­ing towed up a long in­cline. Then, fi­nally at the crest, the tow chain would let go and we’d ac­cel­er­ate down the back­side. On the climb, the ap­par­ent wind shifted aft, but then shot for­ward as we rode down the back­side.

Port tack was a whole dif­fer­ent ex­pe­ri­ence. No more roller-coaster ride; in­stead, the waves lifted us up from the side and then set us down a half­boatlength to lee­ward. Over the crest, the op­po­site hap­pened — the back­side of the wave pushed us di­rectly side­ways up­wind, which re­sulted in huge ap­par­ent-wind changes in both strength and di­rec­tion. As the wave moved us to lee­ward, we must have been mov­ing downwind al­most as fast as the wind was blow­ing be­cause the sails col­lapsed. Then, the pres­sure would come back at the crest of the wave and, for a very short time, we sailed in the true wind­speed and di­rec­tion. On the back­side, we surfed to wind­ward and were in full­hike mode, de­pow­er­ing in the dra­matic ap­par­ent lift/pres­sure in­crease. It was an odd feel­ing cy­cling through such rad­i­cal dif­fer­ences ev­ery swell.

Sum­ming up the ap­par­en­twind strength and di­rec­tion changes on each tack: The physics for each tack were quite dif­fer­ent, and the dif­fer­ence in ap­par­ent wind­speed and di­rec­tion more ex­treme on port than on star­board. Yet, oddly enough, the so­lu­tion on each tack was the same: Hold steady at a neu­tral course while ad­just­ing sails and mov­ing body weight. Port tack re­quired ex­treme body move­ments with each mas­sive ap­par­ent- wind change. We of­ten went from full hike in the puff and lift to div­ing to lee­ward to keep the boat from tip­ping to wind­ward. On port tack, we did the same thing, but it was sub­tle.

It was tempt­ing for me on the helm to try and bear off to fill the jib, but re­gard­less of which tack we were on, when we ex­per­i­mented with bear­ing off, no mat­ter how far we bore off, the jib would never fill. The re­sult was a loss of height with no for­ward gain. Like­wise, when the ap­par­ent wind shifted aft and the pres­sure in­creased, it was tempt­ing to go high, but ev­ery time we tried that, I could not bear off fast enough to get back on track and ended up stuck high and slow.

How­ever, trim­ming con­stantly to match the changes was ef­fec­tive. As the ap­par­ent wind shifted aft, we eased the sails to match. When the ap­par­ent wind shifted for­ward, we over-trimmed a lit­tle. There was noth­ing more to do than wait a few more sec­onds un­til the ap­par­ent breeze came back, re­fill­ing the sails.

I ex­pect if there were a sig­nif­i­cant dif­fer­ence in the na­ture of the waves, we might have han­dled them dif­fer­ently. We clearly learned that it’s never ef­fec­tive to bear off when the sails luff from a sud­den ap­par­ent- wind change. If you have a nim­ble boat and the waves are slower, it might work to head up as the wind shifts aft. But for us, the real les­son about sail­ing in large rollers is to steer more or less straight and use our body weight and sail trim to ad­just to ap­par­ent-wind changes. Q

As the ap­par­ent wind shifts aft, we ease the sails to match. When the ap­par­ent wind shifts for­ward, we over­trim a lit­tle. Wait a few more sec­onds un­til the ap­par­ent breeze comes back, re­fill­ing the sails.

: PHOTO STEVE ROSS When faced with large seas at the This­tle Mid­win­ters West, the au­thor learned first­hand the ef­fect of un­ex­pected ap­par­ent-wind changes, and how best to sail through them.

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