Thistle Spring Coaching/Tuning Session

Paul Kreitler

Saturday, April 11th, Skip Dieball of Quantum Sails Toledo came to Leatherlips YC to run a coaching/tuning seminar for the Thistles.  Approximately 30-sailors converged on the club house around 10 AM for an excellent presentation on Thistle sailing while enjoying hot coffee and bagels from Panera Bread.  For an hour and forty-five minutes, Skip covered a wide range of topics ranging from boat set up to sailing the Thistle flat and fast.  He spent a lot of time discussing the dynamic bending of the Thistle (and other boats) mast and how this dynamic bend influences sail design.  He talked about how important mast set up is on land, but how you can’t really tell if a mast is set up correctly until you’re on the water.  He showed a number of photographs of Thistles with either too much dynamic bend or too little to demonstrate how the mast set up effects the sail shape on the water.  Skip also mentioned that it is very difficult to see the nuances of the sail shape from inside the boat and that pictures from outside are the best analysis tool.

Some points from the talk that I remember:

• Sails are designed to use the dynamic bending of the mast.  So diamond tension is important.  The best starting place is to set up the mast and diamonds according to the tuning guide for your sail cut.  Then, you need to go sailing.  Depending on  the conditions or crew weight, you may need to adjust your diamond tension if the sail doesn’t have the right shape. 
• Indicators on the main that the mast is set up right: Speed wrinkles in the forward third and leach twist two-thirds up the back of the main (just above the numbers).  Speed wrinkles that are too few or too long  indicate too little mast bend.  Speed wrinkles that are too many or too long indicate too much mast bend.  The leach twist location indicates how the top of the mast is bending with crew weight and wind conditions.
• The jib and the main work together.  The jib directs the wind across the back of the main to create lift, so its set up is important.  Follow the sail maker’s tuning guide to properly locate the leads in the boat.  When setup properly, the leach of the jib should be parallel to the luff of the main as you look from the bottom up.  Skip has started using barber haulers in chop to flatten the jib.
• In the words of Mike Ingham, focus on the big lines such as the sheets and vang.  The smaller control lines are less important such as the traveler, outhaul, and cuningham.  They are still important, mind you, but don’t let them become a distraction.
• Utilize the vang upwind in heavier air to induce mast bend and flatten the sail.  The boom can take a lot of vang in the Thistle, just remember to take it off before turning the corners.
• Sail the boat flat with the transom just above the water to reduce the wetted surface.
• Rig your boat in a crew-friendly manner so lines are easy to access and people don’t get hurt.

Following the morning talk, the LYC Learn to Sail program provided a delicious lunch of burritos and brownies in preparation for the afternoon racing.  And we needed the energy.  The temperature had risen to a balmy 50-degrees and the wind had settled to between 15-20 mph from the north.  The combination of cold water, cold air, and high winds kept four of the ten teams on shore for lack of proper gear.  At the skippers meeting, it was decided that no spinnakers would be flown to prevent capsizes.

Race committee John Rupert, Erin Sherer, and Nick McMahon set up a great windward-leeward course between marks 4 and 1.  The wind direction stayed steady out of the north for three great races.  Bob McNitt kindly drove Skip around in a skiff so he could video the races and provide coaching advice to the sailors.  By the time everyone went in, there were no protests, no capsizes, some slightly cold fingers, and some big smiles.

The crew reconvened in the club house for beer and pizza while Skip analyzed the racing video.  It was an incredible teaching tool to see mark roundings and upwind sail trim played back on the screen.  Some things that Skip noted for everyone:

• Some people could use more vang upwind.  Some people, such as myself, could use more downwind.
• At leeward mark roundings, we need to work on entering the turn wide and finishing tight.  All while keeping the boat flat.  The jib shouldn’t come in too quickly or it keeps the bow down.
• We were all a little late when reacting to the puffs coming down the lake.  When the boats heeled over in the puffs, they would slide to leeward.  Skip recommended preemptively adjusting crew weight and sail trim before the puff arrives.

In summary, it was an awesome day in the classroom and on the water.  Many thanks to Skip for setting us out on the right tack!