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Thread: Weather/Tactics Discussion (Part 3)

  1. #1
    Join Date
    Sep 2007

    Default Weather/Tactics Discussion (Part 3)


    West of the Gulf of the Farallones lies the “WINDY REACH.” In late June, early July, the EPAC High is centered 80% of the time north of 28N and west of 133W. Between the EPAC High, and Low pressure inland over Southern CA/Arizona flows a cool NWerly breeze from 310 m called the WINDY REACH.

    Crossing the WINDY REACH, we steer for a critical waypoint I like to call "Pt. A." This mythical Pt. A lies somewhere on a north/south line along longitude 130W. The reason Pt.A is such a critical point is that in a typical year, Pt. A lies on or near the SE RIDGE or lobe of the EPAC High. Once you cross this RIDGE of lighter winds, barometric pressure stops its slow rise, the wind comes aft and builds, and the NE Trades fill in south of 29N x135W.

    To paraphrase Stan Honey,

    "As you left the Coast you made your decision where you wanted to cross the RIDGE (130W), you sailed there, and now you have to live with it for four or five days. If you are too far to the north, you will be slowly destroyed by the yachts to the south of you, and there is nothing that you can do about it..."

    Stan goes on to say: "The central question concerning course selection is: how close to sail to the High, or how many extra miles to sail to get farther from the High. In years when the Pacific High is weak or weakening (<1026 mb) and positioned well south, there can be strikingly more wind to the south. This condition can persist for the entire middle third of the race. Occasionally, however, the Pacific High will be strong or strengthening (>1032 mb), and located far to the north. In these conditions, it IS possible to be too far south. The boats that sail closer to the high will not only get more wind, but will sail the shorter distance.

    If you are racing a light displacement boat, it is likely worth sailing extra miles to the south to cross the WINDY REACH on a broader point of sail. Then after crossing the RIDGE, a ULDB may well have more wind to the south to mitigate the extra miles sailed.

    On the other hand, a heavier displacement boat that reaches hull speed sooner may not need to reach to the south to find a better wind angle and/or more wind. The average speed of a displacement hull will likely not pay for extra distance sailed to the south.

    Thus the axiom has grown over the years that for the SHTP, heavier displacement boats can sail closer to the EPAC High and plod down the Rhumb Line at hull speed, sailing minimum extra miles, while the ULDB's burn up the ocean further south, sailing several hundred miles more.

    Whether this axiom is true depends, like most everything else in this race, on the location of the center of the EPAC High.

    Crossing the WINDY REACH, the barometer will slowly rise from approximately 1015 mb. near San Francisco to near or slightly above 1020 mb. at Pt. A. It is best to maintain a distance of at least 7-8 millibars from the center of a moderate strength EPAC High (1026-1032 mb.) In other words, if the EPAC High center is forecast to be 1028 millibars at position 38N x 145W, a safe place to cross Pt.A would be near the 1020 or 1021 isobar. probably near 33N to 34N.

    Keep in mind the center of the EPAC High can bounce around many hundreds of miles in just a few hours. Usually this change in position of the jello like EPAC High predominantly varies in an E/W direction, more than N/S.

    Depending on the position of the High, and its circling isobars, Pt. A could be crossed as far south as 27N x 130W in an abnormal Transpac year like 1979 and 1980, especially if the High is weak and well to the south.

    Or as far north as 34Nx 130W if the High is strong and anchored well to the north and east, offshore of British Columbia.

    Generally, Pt. A sits somewhere in the vicinity of 31-33N x 130W. You do not have to sail directly through Pt. A. It is only a reference point to aim for. If you happen to see a buoy marked "A" near 32x130 as I once did, you might want to think about catching up on sleep.

    Crossing the WINDY REACH in rough conditions, as well as ship's leeway, there is a surface current up to 1 knot flowing North to South to add to computations.

    In 25 knots of NW wind, you might be sailing at a speed of 6-7 knots to the SW. But also making 1.5 knots of leeway and drift to the south. For the first three days of the SHTP, I add in 10-12 steering degrees, or 35 miles/day, of southerly set.

    Just before the sun sets on the first night of the SHTP, somewhere abeam the Farallone Islands, it is time to take stock as to what sail combination will be best to wear entering the WINDY REACH. Although a half moon will be overhead this year at the start, after dark in rising wind and seas is not a good time to be experimenting with sail combinations and steering adjustments.

    In a normal year, or 50% of the time, the NW GRADIENT wind will blow 20-30 knots during the WINDY REACH. A reefed or deeply reefed main is often the best choice. As is a small, or reefed headsail. Familiarity with one's boat pays dividends: The key is having an almost neutral helm. Severe weather helm will soon overwhelm an autopilot, or put the windvane into a state of rebellion.

    With a 310m True Wind Direction (TWD), and a boat speed of 6-7 knots, the Apparent Wind Direction (AWD) on a course steered of 225m will be about 75 degrees from the bow. Or a Close Reach/Beam Reach point of sail.

    In 25 knots of wind, for best neutral helm, the working sail area will be concentrated forward. A #4 jib, staysail, and double reefed main was the standard combination WILDFLOWER carried crossing the WINDY REACH. In the 1978 SHTP between 0300 and 0900 hours on the first night/second day, I dropped the main altogether in 30 knots of wind, and carried on under #4 and and working staysail.

    The windward jib sheet can be led around to the leeward rail for an outboard lead that opens the slot. And provides a safety backup.

    Unused working and storm sails, less spinnakers, can be securely lashed to the weather rail. Sails lashed to the weather rail help divert water on deck from gushing aft into the cockpit.

    Before dark the first night on the WINDY REACH I recommend making sure all gear that can be washed overboard by a breaking wave coming from the starboard beam is well secured: safety lines on solar panels, a safety line on the above deck tiller pilot, and a line securing the windvane sail to the boat. Also, if you carry cockpit weather cloths, the leeward (port side) weather cloth should be removed. And the windward (starboard side) weather cloth secured with breakaway ties on its bottom edge.

    Loose halyards are best tied off from the mast to prevent distracting slapping and chafe during the night.

    All loose sheets, halyards, and reefing lines should be well stowed so their tails don't wash overboard and tangle in the prop or rudder. Through hulls closed and pressure water systems turned off. A hospital urinal serves as a pee bucket, and can be emptied out the companionway hatch.

    The computer is either well secured with lid closed, or stowed out of Harm's Way altogether. And an assortment of flashlites are readily available. Including a bright spotlite for illuminating sails if oncoming commercial traffic is in the area. Ambient illumination in the cabin is provided by several glow sticks. Foam ear plugs help reduce the cacophony of sounds, but are removed at regular intervals to listen for ?. If it is really rough, I wear a bicycle helmet, or double watch caps for head protection if thrown across the cabin.

    If you are sleeping to weather, a full length lee cloth 12" high above the bunk cushion, is the only thing short of seat belts that will keep you in the bunk. Alternatively, resting on spinnnaker bags, pillows or a bean bag on the cabin sole is at the least point of motion, and provides ready access to the AIS and cockpit.

    Handy wipes, wash cloths, and a thermos of hot water help keep facial salt encrustation at bay. At night, KGO talk radio, AM 810, can be listened to almost halfway to Hawaii.

    As it begins to get dark he first night, I like to identify boats in the vicinity, enter their bearing and distance on my plotting sheet, and note their running light configuration.

    Commercial shipping from Panama to Asia crosses the fleet at right angles during the WINDY REACH. Mysteriously, it seems if there is a ship in sight on the horizon, there is a 50% chance it is on a collision course.

    On deck, a tether should be snugged to windward with no slack that could potentially launch the skipper across the cockpit. Just being clipped to the jackline is not sufficient in breaking seas: take a couple of wraps around a weather winch.

    The WINDY REACH, the first third of the SHTP, can be exhilirating if prepared mentally and physically. Or terrifying if breaking seas are ripping gear from the boat, the cockpit is filling, and the cabin is in disarray.

    If a repair or sail change is in order, consider bearing off downwind to an AWA of 165 to lessen the impact of wind and seas while on deck.

    After 36 hours at sea, the wind and seas will slowly begin coming aft, the motion will steady, and maybe it's time to shake out a reef. Just don't forget the reef ties.

    GAME PLAN for the WINDY REACH: Chose Pt.A based on future best estimate of position of EPAC High and the isobars on its southern perimeter.
    Secure all loose gear and line. Keep tether taut if rough. Stay warm. Keep the boat balanced with neutral helm.

    Next up: SLOTCARS
    Last edited by sleddog; 05-24-2010 at 06:56 AM.

  2. #2
    Join Date
    Apr 2010
    San Diego, CA


    This is fantastic!

    Now I just need to draw some lines and "A" buoys on a chart to be able to follow...

    Thanks a lot!


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