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 sheeting |
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 |
| Spinnaker Tack |
tight | ease 15 cm | tight | tight |
| Boom | Centreline | centreline/start to play traveller |
play traveller | play traveller |
| Backstay (upwind) |
from loose to 1/3 on at 10 kts |
1/3rd on at 10 kts to maximum at 16 kts |
Maximum | Maximum |
| Backstay (downwind) |
Off | Off | 1/3 on at 20kts | full on |
| Jib Cars | 6 showing | 5 showing from back | 5 showing | 4 showing |
| Main Cunningham |
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 (upwind) |
At middle of foot 100mm from boom |
At middle of foot 20mm from boom | At middle of foot tight against boom |
At middle of foot tight against boom |
| Main foot (downwind) |
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. |
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Cruising, Racing and
Lightwave Endurance Sails
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