SEATTLE Sailing Club Fearful Symmetry J 80, Быстрый старт, Страница: 19 / 34

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J-80 Tuning Guide (cont.)
With 10 to 12 knots of breeze the mainsail is flattened slightly by bending the mast through
main sheet and backstay. Mainsheet is tightened so that the top telltale stands behind the sail
for 20% of the time. Harder sheet enables the boat to take more height. The boom should still
be in the middle of the boat but the outhaul should now be all the way out to the black band
and the Cunningham should be adjusted so that most of the wrinkles in the luff, but not all,
should disappear. This is maximum power trim, if your crew is light you will be over powered
soon, if you are heavy you will be able to hold this trim longer. Depending on the weight of the
crew full power situation should be met at around 12-14 knots of wind. To minimize the healing
moment and to increase speed with this wind strength more back stay is needed, and the
traveler should be lowered to the center line.
The mainsheet should be used so that the mains top telltale is not stalled. This will reduce
speed in these wind strengths. The mainsheet is the most dynamic trim function and should be
trimmed continuously with every puff and lull. The backstay is also a very important trim
function in medium to heavy breezes. Through the fact that in the gusts the back stay flattens
both the mainsail and the jib so that the boat stays flat and fast. But for example in a situation
where extra height is needed (say for instance rounding the leeward mark with a boat to lee)
easing the backstay will close the leach and the boat will sail high without loosing drive.
Through playing the backstay mainsail trim can be prioritized between extra speed or extra
height. With about 16 knots the Cunningham can be tightened so hard that all the wrinkles
disappear in the luff of the main. Draft is moved forwards and the leach is opened even more.
In winds over 20 knots the main should be completely flat and the sails lower third should do
all the work. Out hall, Cunningham and kicker should be on all the way. The kicker makes the
mast bend in the lower third making the mainsail even flatter. The traveler should be 15
centimeters below the center line. How much power the mainsail gives is regulated by the
backstay. Don't be afraid to put a little bit of extra on. In gusty winds the playing of the back
stay is not quick enough to keep the boat on it's feet without the traveler being dumped at the
same time. The traveler should be eased so that the boat finds it's balance, especially in big
waves (which are often found at these wind strengths). With the right trim the boat should be
leaping over the waves. If the boat feels heavy or wants to gripe to weather it is a sign that the
mainsail has too much power´.
When the mainsail is properly trimmed, i.e. flat and with an open leach the boat should feel
well balanced and easy to steer.
Jib Trim
Three functions control the jib; sheet, lead position and halyard tension. The sheet works on
twist and how flat the sail should be sheeted. The jib should have the same angle attack up the
entire height of the luff and the leach should match the mainsails shape. The lead position
dictates the depth of the jib in the lower third and the amount of power the leach produces.
Fast trim - flat water: The lead position should be aft so that the lower part of the jib is flat and
the middle batten is parallel with the center line. Power trim - waves: Lead position moved
forwards to give a deeper bottom third and close the leach slightly. Halyard tension controls
draft position, mainly in the top. Slight amount of halyard tension in light and medium winds
gives the sail it's designed form. In stronger winds it helps with more halyard tension to twist
the jib open, and helps the draft from slipping backwards.