Upwind trim analysis (2005, Schwenk)

UPWIND SAIL TRIM TUTORIAL

Mr. Mike Parramore snapped these photos during Jet frostbiting last week (Feb, 2005). They show a few things that are difficult to describe, but much easier to see in pictures. Virtually everything that I am about to say is borrowed unashamedly from real sailors like Greg Fisher or Greg Koski … but I hope that you find this helpful.

Both boats in the foreground (McKennas, 1140; Johnson/Cotell 1081) are flying early 2000 vintage Doyle/Koski mains on DM-1 rigs. Both boats have Doyle jibs.

trim analysis2 trim analysis1
McKennas:
1. Acceleration form: they are coming off the line using exceptionally fine form. Weight together; their boom is cocked up somewhat, indicating that they do not have yet trimmed down the main and they have a slight heel on. For acceleration in these conditions, this is perfect. Once up to speed, the boat should flatten, the mainsheet in a few clicks, and they should probably hike a touch – they would then be in full-on upwind mode.
2. Jib tension: note the slight crows feet coming in horizontally from the leading edge of the jib – this is is a way to read the amount of forestay sag. Appropriate sag (per the experts) is indicated by a bit of crows feet.
3. Overall: weight nicely together and forward for flat water. Perhaps a bit low in the groove?
Johnson/Cotell:
1. Acceleration form: they are in the backwash from the McKennas, but perhaps a bit too tight, a bit too flat?
2. Jib tension: only wrinkles I can see are those that are running out in all directions from the tack. No horizontal wrinkles would seem to indicate too much forestay tension.
3. Overall: weight also nicely together and forward. Tiller properly in front of the body, and overall looking stable and comfortable. Jib telltales showing perfectly in the acceleration groove.

 

 

trim analysis3

The two boats together, same day, different race. The main sets here are virtually identical – both with horizontal wrinkles running a bit more than a third of the way back. Fisher would say a bit more Cunningham: Koski would set it pretty much like this, I think. Neither shows “overbend” – that would be a longer crease running from about the spreaders back toward the clew. The booms here are just about even – indicating similar levels of mainsheet tension. One gets the sense again, however, that jibstay on 1081 is tighter – perhaps a touch too tight.

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