Jib Sheeting Angles

[Phil Alderson]

Typically what angle from the centerline do people sheet the jib to?

does anyone adjust it in light and windy weather?

[Tim Noyce]

I dont know the angle without looking...

and as far as adjustment, we generally only adjust ours on the clew board. middle hole for light - medium, then sometimes move to the bottom when it is honking to open the leach a bit. Ours sheets to the end of the track (but being such a narrow boat at that point that may not actually be out very far in real terms). We didnt really like the adjustment available using the pegs through the track, so we have a spliced rope attaching to the king post from the car, and so its infinitely adjustable by just varying the splce.

[phil_kirk]

Slippery's jib track is 60cm long. It is about 1.6m back from the snout.  No science behind that though.  The jib car goes the the end of the track we can't adjust the vertical sheeting angle unless we set the jib higher on the luff wire.

All appears to work well and we get good pointing and speed from it.

On E-numbers the track spans from gunnel to gunnel which is a bit longer than slippery's track.
The distance from the snout is about 1.96m.  i suspect the angle will be quite similar to slippery's.  We could limit the angle by a similar method to Tim's and may do so to stop the car mashing the support at the end of the track.

It would be interesting to start a library of key measurements for each boat of the class to act as a library for future designers/builders/modifiers to use as a baseline.

[Phil Alderson]

So from a bit of trig Slippery has a sheeting angle of 10.62 degrees.

It would be good to get key mesurements from a load of boats to give some idea of the variation and of baseline figures.

[phil_kirk]

I not'iced at last year's nationals that Scum Bag's jib car was closer to the centreline but the jib was set with more twist.  I must admit it did look a good fit with the shape of the main at the time.

 Im kae this point because we should be aware that the sheeting angle only fixes the angle of the foot.  The vertical sheeting angle will determine the amount of twist and hence the angle of the sail to the centreline further up the rig.