Level 11: Spinnaker Trim

Crew positions: 

Spinnaker-trimmer (was Genoa-trimmer) with the spinnaker-sheet at the highside chainplates.  Checkstay-trimmer at the leeward secondary winch with winch handle in the winch.  Guy-guy (was Genoa-tailer) at the windward primary winch.  Mast-man#1 at the uphaul winch.  Bow-man is on the windward side of the boat looking back to forecast the wind with the lazy-guy in his hand.  The rest of the crew is positioned to keep the boat level and on its lines (keep the transom out of the water).

Trimming: 

Spinnaker trim is a continuous process that involves three functions.
1)  Set the pole angle.  The primary control for this is the guy.  To get a rough setting of the angle trim the guy until the pole is perpendicular to the apparent wind.  To fine tune the setting, look at the war the spinnaker luff flies as it rises from the end of the pole.  If the luff is leaning off to leeward, ease the pole forward.  If it's billowing out to windward, square the pole back. 
2)  Set the pole height.  The primary control is the uphaul.  The goal is to position the end of the pole so that the tack and clew are level.  In light air try raising the pole a few inches to encourage the clew the rise, encouraging lift.  When running in a strong breeze, drop the pole a few feet and ease it forward to prevent rolling. 
3) Sheet for a curl.  The controls for adjusting the curl are the sheet and guy, working together.  Ease the sheet until the luff of the spinnaker starts to curl to windward.  This shows that the spinnaker is not overtrimmed.  Overtrimming is always slow!!!!
Spinnaker trim requires cycling through the three functions constantly, especially if the apparent wind direction is varying.  The sheet and guy should never be cleated off!   The downhaul must be adjusted as the pole angle and height are adjusted.

See "Understanding Trim", Peter Isler, Sailing World, May 1996 and Chapter 8 of "Racing Crew", Malcolm McKeag & Bill Edgerton, Fernhurst Books, 1995.