J-105 Tuning Guidelines

Our base settings are at 10 to 12 knots of wind, in the ocean, tensions measured with a LOOS RT-10M Rod Gauge. Basic setup consists of maximum headstay length with the jib tack as low as possible. To achieve this the lower end of the turnbuckle must be screwed in as far as possible and use the shortest shackle possible on the tack. If you can’t screw the upper end of the turnbuckle out far enough to get a maximum length headstay you may have to add a toggle at the top.

The base position for the jib lead is set so that the centerline of the sheave is 15′ 2″ from the tack pin.

True Wind Speed Cap Shrouds D1 – Lowers D2 – Intermediates Jib Lead
0-6 Knots -3 -2 -6 Forward 2 Holes
0-6 Knots / Flat -1 -1 -6 Forward 1 Hole
6-9 Knots -1 1/2 -1 -3 Forward 1 Hole
6-9 Knots / Flat Base -1/2 -3 Base
10-12 35 4 14 15′ 2″
10-12 Knots / Flat +1 + 1/2 +1/2 Back 1 Hole
13-15 Knots +1 +1 +1 Back 1 Hole
13-15 Knots / Flat +1 1/2 +2 +1 1/2 Back 1 Hole
16-20 Knots +1 1/2 +3 +3 Back 1 Hole
16-20 Flat +2 +4 +3 Back 2 Holes
20+ +2 1/2 +5 +4 Back 2 Holes
20+ / Flat +3 +5 +4 Back 2 Holes