Stavanger, Tuesday
Hi Mark.
Finding the best rig for a given hull is both easy and difficult. It is easy because most boats will move about in a fashion whatever rig you fit, but difficult if you are aiming for the best performance as a combination of speed, handling, safety and economy.
On the 20th. November David T wrote here:
"...The sail should be built with cambered panels, for sure, to get sufficient drive. The planform of Peregrine's sail, based on the well-tested Hasler/McCleod design principles, is easy to understand and to make, for your first venture into junk rig, and if made with deeply cambered panels, up to 10% camber, will work well. But if you are able to put in a little more work into the understanding and building of a fanned planform sail, I feel that it would pay dividends...."
Of course I agree with what David says about camber. I have experienced the same. However, I’m sceptical to the hint that the fanned sail is an improvement over a fully cambered HM style sail (except for looks if you prefer them). So far I haven’t seen any evidence that the fanned sail has proven to be better with respect to speed and handling. When David participated with his Tystie in the first JR rally in Stavanger, in 2004 (light winds, F2-F3), Tystie was not performing that well. I won’t compare her against my light and generously rigged Johanna. Instead I will focus on Samson. Samson is a 49’ schooner (a stretched Samson C-Deuce). Her 23tons, acres of wetted surface and 3-blade, fixed propeller are driven by only a 107sqm sailarea, divided on two cambered panel HM style sails. Still Samson went noticeably better than Tystie and could tack around without needing the engine. So what if there had been more wind? Forget it; from a mid F4 Samson will walk away from anyone.
Conclusion: My armchair hunch is that there will not be much difference in performance if you fitted two sister boats with the same sail area of cambered junk sails, one being the HM type and one being fanned. They both would easily walk away from a third boat fitted with a flat sail.
Arne
PS: I suggest you look up the reports from the rallies in 2004 (NL44, p.18 and p.22) and 2008 (NL52, p6 and p.30). The gorgeous photo of Samson (thanks to Peter Manning) in NL52 p.30 should say more than words.