Jib adjustment is critical to having a good upwind angle, as well as good boat speed for given wind conditions. On how the barber works we recommend this in-depth study, today we are going to see instead how to read the threads on the sail and adjust the sheet tension.
Jib adjustment – Watch out for the windward marker threads.
On the jib or genoa we will find at least two sets of fillets on the sail, near the luff, one set at the top, and one at the bottom. The ones at the bottom are mainly used to tell if we have the right sheet tension: when they are all parallel the “trim” of the sail is the correct one, but if they fall downward it means we have caulked the sheet too much. If they point upward we have fucked too little.
Adjusting the bow – Understanding when to let go
The series of threads at the top will give us similar indications, but will also tell us whether the sheet point is in the correct position. If the point is too far back at the top of the sail, a hint of foiled bubble may be created with the fillets pointing upward, at which point the carriage position will need to be advanced toward the bow until the right balance is found, also depending on the wind speed and strength. Sheet and jib carriage should be adjusted to match.
Finally, we also often have windward marker fillets, usually 1-2 at the top of the sail, placed in the leech. If these leech threads come out stretched correctly the trimm is right, if they hide it means the adjustment is not perfect and a few cm of sheet should be left.