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Sail & Rigging - Optimal sail plan / racing
13 November 2023 - 20:45
Join Date: 01 December 2019
Posts: 21

Optimal sail plan / racing

Hi all,

We've started to do a bit of racing, but feels like our PHRF rating (69 for our Swan 47, for Northern California) is assuming we are much faster than what we can do.

Started to wonder if my genoa is a bit too small for the weather. It seems the sail plan calls for a #2 genoa for all the way till 19-26kts of apparent wind. I'm ususally using a smaller headsail in that wind.

- do you find this sail plan accurate?

- What size Genoa do you use in 13-20kts of apparent wind and what do you use in 20-25kt apparent wind?

Trying to understand if I can change something... Unfortunately my smaller genoa is much better than the larger ones, so I end up taking the smaller / better shaped genoa vs the bigger but older genoa. But I seem to be slower than competiton


15 November 2023 - 22:29
Join Date: 17 November 2016
Posts: 28

We need all the horsepower we can get from our headsails. We use our full-hoist 3Di #1 up to 22 knots apparent and our furling #1 up to 25 knots apparent. Our #2 is smaller than 135% and is quite slow in anyting under 20 knots.

Douglas - Swan 47 - Till


#1 3Di

30 November 2023 - 18:13
Join Date: 01 December 2019
Posts: 21

Thank you so much this is very helpful.
I think I'm flying a job too small :)

I just need to get a good quality #1.


11 December 2023 - 14:56
Join Date: 16 October 2011
Posts: 5

Headsail area is an interesting debate: at some point a Genoa too small for the conditions can not deliver the required power. In my opinion, beside talking about surface it is also very important refer to specific sail shape differences. 

Original S&S Sail Plan on the upper left corner feature a box including a number of Headsails for a comprehensive Racing Inventory: as many as 7 pieces plus one optional Light Reacher for Offshore races.

Please see below Image 1.

At the times they were all built Cross-cut paneled in Dacron cloth, with a quite limited range. Sailmaking technology has grown fast in the last few decades: I’d like to give two different Headsail shape samples, built with different materials. 

1 – Genoa 1, LPG 150%. Powerful cross-sectional shape, effective up to AWS 17 kts. Fully trimmed-on at lower range, Lead forward to make enough speed that is crucial before heating-up. Main traveler a few degrees high to have Mainsail Foot in the centerline. Maybe at the upper end the lead position moved aft allowing for more upper Leech twist: an effective de-powering trim combined to low-stretch material to avoid too much heeling component, maintaining Max drive force. See below Image 2  

This paneled Genoa made in NorLam-Ultra Dyneema laminate: mostly 6oz except being 8oz in the Head and lower Leech Clew portions, light also in all corner patch layers. A similar layout built in woven Dacron for this wide range would be much heavier together with a shape growing fuller at higher range that is not a good thing. Anyway, compared to an original Cross-cut panel layout, this Tri-Radial structure at least is keeping the shape at the right place, without shifting back pretty soon, to become more curved aft than in the front: very poor drive force with a greater heeling component. 

2 – Genoa 2, LPG 140%. Completely different shape, less deep, much straighter in the back and twisted. Breeze is on, there is no need to search for power, rather to let it escape when a stronger puff is coming. See below Image 3.

This shape can be effective from 15 TWS, or even less in flat water, up to 25 knots and above, with one reef in the Mainsail as soon as helm balance call for it. 

This 3Di structure made in Aramid/Dyneema mélange has a very long lifetime. In absence of any stretch, a small Lead position change can allow different setting should the wind speed change either way. 

Beside my comments, I think these two shapes will be effective obviously in very different conditions. Since this thread has been started talking about a lack of power with a too small Headsail, in presence of other larger Headsails with some kind of performance issues, I just wanted to show how much different shape Headsail can be made, though not necessarily with lots of area difference. 

In case of a single Headsail inventory, I would find a compromise in between: enough power to wake-up in the light pressure, but made strong enough to survive well in an extremely wide range. 

1 - S&S Original Sail Inventory, now simplified (in grey)

2 - Genoa #1

3 - Genoa #2

11 December 2023 - 15:02
Join Date: 16 October 2011
Posts: 5

Below, on board VANESSA (Swan 47 #69) a Genoa shape featuring both power and straighter back sectional shape, a good compromise for a single Headsial "All Round" inventory. 

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