tel: +44 (0)23 8045 6205

j70 tuning guide

Base Settings: Are the starting point for all rig settings and are used between 12 - 16kts. It is always a good idea to adjust all rig settings back to base at the end of a days sailing otherwise it is easy to forget or lose the reference point.


Forestay Length: Pull the forestay tight against the mast and mark it where it meets the top of the white band at the goosneck. (Use a permanent marker). alternatively if the mast is hoisted take the Jib halyard to the same band and then swing it out to the forestay and mark that point. Base forestay length is measured from the mark on the forestay to the centre of the pin at deck level.


Jib Cars: As supplied by the manufacturer with holes numbered from 1 going Backwards


Cap shrouds, D1s and D2s: Base settings measured with Loos PT2M rig tension guage. Light and Heavy settings achieved by adjusting bottlescrews on or off from the BASE settings.


Tips: With the swept back spreader rig it is important not to over tension the cap shrouds or the mast will compress and fall off at the top.


Hints: The aim with D1s and D2s: adjust until the mast is straight sideways when sailing upwind. Mark all the bottlescrews so that it is clear the correct way to turn if you want to tighten or loosen the rig!


Wind strength 6 - 12 kts 12 - 16 kts BASE 16 - 20 kts 20kts +
Windrard Jib
50mm in 50mm in - clew
near cabin top
25mm in 0mm
Cap shrouds - 3 turns 25  - Loos PT2M + 2 turns + 4 turns
D1s (lowers) - 2 turns 15 - Loos PT2M + 1 turn + 4 turns
Forestay - 3 turns 1.43m + 3 turns + 5 turns
tight ease 15 cm tight tight
Boom Centreline centreline/start
to play traveller
play traveller play traveller
from loose to
1/3 on at 10 kts
1/3rd on at 10 kts
to maximum
at 16 kts
Maximum Maximum
Off Off 1/3 on at 20kts full on
Jib Cars 6 showing 5 showing from back 5 showing 4 showing
Slack Take up slack tension then tighten fully at upper end of
wind range
tight on
Jib luff tension Horizontal
creases just showing
Horizontal creases removed Tight Tight
Vang (upwind) Slack Take up slack Just tight  > tighten
fully at upper end of
wind range
Just tight  > tighten
fully at upper end
of wind range
Main foot
At middle of foot 100mm from
At middle of foot 20mm from boom At middle of foot tight against
At middle of foot
tight against
Main foot
At max depth 50mm from boom At max depth
100mm from boom
At max depth
100mm from boom
full on
General comments:   Fit backstay flipper to clear mainsail leech in light winds. 
Keep boom on centreline as long as possible.  get onto
back stay early.  Jib halyard tension and sheeting
position quite critical. Make sure mainsail is always
hoisted to band - mark halyard.  


Unit 19 Hamble Yacht Services
Port Hamble
Southampton, SO31 4NN
+44 (0)23 8045 6205