http://www.sejl.dk                     Sail trim

?

SAIL TRIM

These are the sail trim guidelines which work well on Diva boats

SPINNAKER:

  1. BROAD REACHING/DOWNWIND: Do NOT overtrim. "When In Doubt, Let It Out." The spinnaker sheet trimmer is constantly busy. The spinnaker should be just shy of the edge of collapse. You should rescue it from a curl frequently. If the spinnaker is touching the headstay it is DEFINITELY overtrimmed. If easing the sheet causes collapse, then check pole height (Are the clews the same height?) and pole position (Is the center seam parallel to the mast?)
  2. POLE POSITION while BROAD REACHING/DOWNWIND: Pole should be square (90 degrees) to the wind. Check the masthead fly. Keep the center seam parallel to the mast - if the seam slopes to leeward aloft ease the pole forward (& vice versa).
  3. POLE HEIGHT while BROAD REACHING/DOWNWIND: The luff should curl first just above the cross-cut panels. If the pole is too LOW, the TOP WILL BREAK early; if the pole is too HIGH, the BOTTOM WILL BREAK early. The pole is higher in heavy air & lower in lighter air. In very light air when it can barely lift and fill, lower the pole radically. A bottom break is deadly because it will collapse the whole spinnaker.
  4. TRIM while TIGHT REACHING: You are flying the spinnaker like a genoa.
  5. POLE POSITION while TIGHT REACHING: 1-2 feet back from the headstay
  6. POLE HEIGHT while TIGHT REACHING: If you are having trouble carrying the spinnaker, the pole should be low with very tight downhaul. Windward clew (at pole) may be lower than leeward clew. Another school of thought is to try the pole high.

 

GENOA:

  1. RUNNING BACKSTAY TENSION affects fairlead position dramatically. In heavy air & flat water the headstay should be tight for maximum pointing ability. In light air or chop, the headstay should be loose for maximum power. Set the fairleads after you have decided upon windward running backstay tension. Off the wind, the runners should not be very tight.
  2. FAIRLEAD POSITION: The genoa telltails should break evenly along the luff. If the TOP LUFFS before the bottom, move the LEAD FORWARD (increasing leach tension & reducing twist). If the BOTTOM LUFFS before the top, move the LEAD AFT (relaxing tension on the leech, allowing the clew to rise & the sail to twist). In light air the fairleads move forward; in heavy air the fairleads move aft. If the top of the genoa is tight into the top spreader while it is flying away from the lower spreader, move the lead aft to open up the top of the sail, making it possible to trim the genoa closer to the rig.
  3. TRIM: If the WINDWARD TELLTAILS break, TRIM the genoa in or have the helmsman fall off. If the LEEWARD TELLTAILS break, EASE the genoa out or have the helmsman come up. It is deadly slow to sail with the genoa overtrimed (i.e., leeward telltails breaking).
  4. OFF THE WIND (REACHING): Barber-haul by putting a block on the rail at the spot just underneath where the sheet intersects the rail. This will prevent the leach from twisting off. Do NOT overtrim. If the telltales are not drawing try easing the sheet(s) until the leeward telltales start to flutter (meaning that the genoa was overtrimmed); continue easing until the leeward telltales are streaming.

 

MAINSAIL:

  1. Mainsail trim is critical. It affects the helmsman's ability to maneuver the boat. Going to windward (and while maneuvering) in heavy air, a good mainsail trimmer is effectively steering the boat with the helmsman. Under these conditions, an inattentive mainsail trimmer will destroy the performance of the boat along with the helmsman's ability to steer it. Keep at least the top leech telltail streaming.
  2. WINDWARD (general principles): Top batten parallel to the boom. For maximum pointing in flat water, introduce a slight hook (reduced twist); to increase power in chop, let it fall off slightly (more twist). Maximize power, weather helm, and angle of heel by bringing the boom to centerline (but no higher). When the boat is overpowered (the helmsman has too much helm and/or the boat heels more than 30-35 degrees), ease the boom to leeward.
  3. MAST BEND: Tighten the backstay to bend the mast and depower the mainsail. The luff will become looser (tighten the cunningham). It will also be necessary to tighten the mainsheet. A diagonal wrinkle running from the top/middle of the mast down towards the mainsail clew means that the mast is overbent. The checkstay can be tightened to take the bend out of the middle of the mast and remove the wrinkle.
  4. LIGHT/MODERATE air going to WINDWARD: Use the mainsheet to set the top batten parallel to the boom. Use the traveller to place the boom on centerline and (if the helmsman asks) ease the boom to leeward during puffs. The helmsman will probably prefer to use the puffs to take bites to windward without the traveller being eased. The eyelet shelf (outhaul) will be used to control the mainsail depth. The luff tension (cunningham) should be moderate.
  5. HEAVY air going to WINDWARD (defined as the traveller is now totally eased most of the time - what next?): "Vang Sheeting" Use the vang to set the top batten parallel to the boom. Use the mainsheet to control power, weather helm, and heel. The helmsman will probably want the boom eased to leeward during puffs and pulled back up to windward after the puff is over (communication is vital). In extreme conditions, someone should be ready to ease (or dump) the vang if the boat starts to go out of control. The eyelet shelf (outhaul) will probably be maximally tight as will the luff tension (cunningham). Beware of letting the main flog - if the mast pumps we could loose the mast (more disruptive than heeling too much). Try to save the mast from pumping by keeping the leech edge of the battens just drawing.
  6. OFF THE WIND: Use the vang to set the top batten parallel to the boom. Use the mainsheet to ease the sail appropriately as the boat falls off and bring it in as the boat comes up. Keep at least the top leech telltail streaming.. The eyelet shelf will be eased unless it is really heavy air. Aggressive trimming is especially important under starting conditions (before the start, the main will be set up for windward work).
  7. GYBING: In heavy air (especially), it is mandatory that the boom be sheeted in prior to being thrown over. Unlike smaller boats and boats with telephone pole masts, our boat could lose her mast if the boom comes over too hard.

 

Crew Weight:

XS has a narrow beam. We need to sail with a greater angle of heel than the boats with a wider beam. The narrow beam also seemed to make her less sensitive to side-to-side trim. We used to think that our crew did not have to scramble to the rail to keep her level. Then we found out that the narrow beam meant that XS is very sensitive to fore-and-aft trim and a cockpit full of crew was hurting us. We need to keep crew weight amidships and positioned inboard or outboard to maintain the required angle of heel (usually 15-25 degrees, depending upon the windstrength.)

 

(thx to Mark & Co, sailing D39 XS, for the sail trim tips)

 

Rope Guide:

RobShip

http://www.robship.se/?page=tagguiden