Mainsail Trim Light Air Medium Heavy

Top Batten

Top Leech Telltale

Outhaul

Backstay

Cunningham

Traveler

Vang

Weather Helm

Prebend

Rake

Outcome Shape

Poked to leeward, open twist. Any chop requires more twist.

Parallel to the boom and even poked to windward in

flat waterOpen twist to depower sail.

Flowing 100 percent of the time to keep laminar flow and

acceleration

Stalled 50-70 percent of the time to promote pointing

Flowing all the time in order to never stall and overpower main

Moderately eased. Possibly tighten in VERY light air to

promote stack up

Tighten to design draft location, loosen in waves

Tight. Lower telltale should always flow

Minimal. If rig is very loose use a little to keep rig from bouncing

Aggressively played in reaction to helm pressure

Maximum on. Watch mainsail luff for diagonal

over bend wrinkles

OffUse to keep draft in design

location

Use to keep draft in design location or further forward. As backstay reaches max

cunningham should be max

Upwind, well above center. Car position is less important than where the boom is - should be

centerline

Boom position still dictates, but due to tighter leech tension traveler is often near centerline or just

slightly above

Lower and lower as sail gets more and more

overpowered

Upwind no tension, down wind little of no tension so as to not

hook leech

Once twist is set for upwind, snug vang.

Downwind use vang to control leech tension

Upwind use to control leech after twist depower has been exhausted. Tight vang also flattens lower

mainsail and allows sheet to act as traveler.

Downwind use vang to control power/twist.

Neutral Neutral to slight tug Slight tug with more in puffs

Matched prebend to sails designed shape

Moderate so that backstay has immediate effect

Minimum so that max backstay doesn’t overbend

main

Max Rake Median

On most boats you want minimum rake in these conditions. Some boat benefit from rake due to

Upwind deep shape, draft aft, twist slightly open and boom on

centerline

Upwind designed draft, little or no twist for max

pointing, tightest possible angle of attack. Downwind

- very powered up

Flat as can be achieved with draft moving forward as sail overpowers. Twist opens to depower, then

shifts to open AoA and no twist

Base Mainsail Set Up - www.galeforcesailing.com - Got questions? Call kb at 202-549-1032