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Tornado Tuning with a Carbon Mast

Written by Paul Raymond. Posted in Tornado Sports Tuning Guide

This article was written by Rolf Nilsen and was published at www.blogspot.com

General

Mast rake: outside corner of transom

Pre-bend (carbon): Spreader tips raked so diamonds are 50 mm from luff track (less for heavy crew/lighter wind, more for lighter crew/higher wind); Diamond tension set to 38 on the new (black) Loos gauge (more for heavy wind/light crew).

Windward

Low winds: 0-7 knots
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Twist (leech telltales): Less important than leech shape. I try to keep leech near center line but not hooked above it. Then steer to get tell tales working.
Foot (distance between mainsail and boom): 2-3 inches from boom at max draft point.

Mainsail draft (leeward and windward telltales, draft position, downhaul): Depending on pre-bend, zero to small amount of downhaul, in order to open the leech and keep it from being hooked. 

Mast rotation: Mast tiller pointed at aft end of centerboard trunk opening. I mark a line on the tramp under the mast tiller (which is the mast-base type).

Jib traveler: Almost no wind, traveler is 45 cm from center line. With wind insufficient to lift hull, it is at 35 cm. 

Distance from jib leech to spreader on mast: This will depend on spreader rake, carbon or alu. Generally, an inch off the tip is OK. Touching is too much.

Jib telltales: Flowing.

What to look for in helming and trimming: Steer by jib and main tell tales. Keep weight as far forward as possible. Generally, this means helmsman at or in front of shroud, crew in front of main beam. Possibly sending crew to leeward to help raise the hull when in enough breeze. I make shroud tension higher for lighter wind (typically 25-30 on Loos gauge)...to reduce forestay sag at lower mainsheet loads. 

Medium winds: 7-15 knots 
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Twist (leech telltales): Still less important than leech shape. I try to keep leech near center line but not hooked above it. Then steer to get tell tales working.

Foot (distance between mainsail and boom): 0-1 inch from boom at max draft point.

Mainsail draft (leeward and windward telltales, position, downhaul):

Downhaul off until double trapped & no longer looking for power.

Mast rotation: Once single trapping, we crank it in to 20 cm aft of the centerboard trunk opening.

Jib traveler: 35 cm from centerline

Distance from jib leech to spreader on mast: Typically 0-1 inches.

Jib telltales: Flowing

What to look for in helming and trimming:: Keep weight forward. Steer for waves/puffs. Give crew mainsheet as soon as single trapped. Play mainsheet to keep hull out as much as wind allows. Crew should crouch in to gunwale in lulls. Keep weight forward/near shroud. After double trapping, start small increments of downhaul to smooth out gusts. Crew works mainsheet to control hull height off water. If needing to move more than 1 arm's length, start adding small amounts of downhaul. Note that going too far is bad...boat is flat, requiring excess footing to lift the hull. Easing downhaul doesn't usually work unless main is also eased. 

High winds: 15-25 knots
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Twist (leech telltales):Flicking periodically is ok

Foot (distance between mainsail and boom): 0-1 inch at max draft point. 

Mainsail draft (leeward and windward telltales, position, downhaul):

Windwards will rarely settle in higher breeze. Downhaul set according to 1 arm-length mainsheet control of gusts.

Mast rotation: 30 cm after of board trunk opening.

Jib traveler: 55 cm off centerline minimum.

Distance from jib leech to spreader on mast: 1-2 inches.

Jib telltales: Try to have them flow, but at higher winds the windwards may never settle.

What to look for in helming and trimming: Steer for swell and gusts on the water. Good communication with crew is important (ie. try to avoid overcorrecting by steering up & easing main at the same time). Some gusts will require luffing up to control the boat (try to anticipate these by looking upwind)...but try to resist luffing as a rule and let the mainsheet control hull height where possible. Once this is mastered, hull should rarely touch the water and boat will surge forward in gusts instead of pop up...quite a noticeably different feel when done right.

Downwind

General Spinaker Setup:

Luff tension/distance sprit/mast blocks: I set spin luff to a fist full able to rotate 60-90 degrees....less for light conditions, more for heavier. I do not measure block distance...this changes with mast rake, downhaul and even rotation.

Spi sheeting point: 
Light air we are at the 3rd tramp lace point. 
Med-High wind we are at 4th lacing. 
Very high winds I might try 5th.

Low winds:
Course/helming: Keep sail loosely sheeted & breathing. Steer to keep sail inflated. Crew to leeward and forward. Helmsman forward and inboard, even right at the mast. Consider helmsman taking the spin sheet for better steering/sheeting coordination, particularly in chop water with light air.

Mainsail twist: Eased to get telltales flowing...traveler might be eased off 3-6 inches in very light conditions.Usually I let off the outhaul fully.

Mast rotation: 90 degrees or more...need to stop it flopping either by holding it or running a rotation lock line of some kind.

Downhaul: Completely off...wrinkles in the main are fine.

Jib traveler: Near full outboard (~55 cm or more if possible).

Jib sheeting: Enough to take flutter out and get most tales working.

Spi sheeting: 3rd tramp lacing point until hull can raise with both crew to windward. Eased as much as possible...may need to oversheet briefly if it collapses...then ease back immediately. Steer to keep sail full.

Medium winds:
Course/helming: Keep sail a bit more sheeted but still breathing. Steer to keep sail inflated, go higher to speed up, then head back down. Aim for small changes of steering angles (~5-10 degrees) to keep speed & hull out longer. Crew to leeward until hull can fly with crew to weather. Helmsman forward at shroud. As wind picks up, helm moves aft to rear beam. Crew might trapeze off stern. Steer down in puffs as speed come up (again, only 5-10 degree angle changes to keep hull out...don't get greedy!).

Mainsail twist: More tension on sheet so that tales are flowing once at speed. Traveller centerline. Outhaul eased to get 3-4 inches of max draft at boom.

Mast rotation: Possibly still at 90 degrees, but in buoy racing, we leave it at the upwind setting since it's too easy to forget to reset for the upwind On the finish legs I will sometimes let it go.

Downhaul: Full ease.

Jib traveler: 55 cm.

Jib sheeting: Enough to take flutter out and get most tales working

Spi sheeting: 4th tramp lacing point once hull is lifting. Eased as much as possible...may need to oversheet briefly if it collapses...then ease back immediately. Steer to keep sail full.

Strong winds:
Course/helming: Head slightly higher & hold for speed to come up, then decide to go higher, hold or steer down as needed. Avoid going up until sudden take off point...you will find you overshoot and become vulnerable to gusts. Small steering inputs going down & up are key. 

Mainsail twist: Sheet tension fairly high to keep tales flowing at speed. Traveller center line. Outhaul 0-1 inches of draft.

Mast rotation: Same as upwind.

Downhaul: Same as upwind or eased back a little from that point.

Jib traveler: 55 cm or more.

Jib sheeting: Sheeted to stop flutter/tales flow.

Spi sheeting: 4th tramp lacing point is normal until very high wind. Enough tension to keep it filled as boats speed comes up. Avoid oversheeting and choking the sail. This forces helmsman to drive higher to get speed/hull up...makes boat too vulnerable to gusts. 

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This article was written by Rolf Nilsen and was published on www.blogspot.com