I would like to think that if you can sail in it, then Savonius will not be optimal solution. Savonius is good only at low winds and when wind direction changes a lot, that is where it is strong, but certainly it is inefficient and that starts to matter when there is more wind which could be harvested much better with some 2 or 3 blade rotor type.
Those huge industrial wind turbines have savonius kind of rotors at top of them, those make emergency power and who knows what else, but that is where those are good, also if one needs fan for ventilation there savonius and other similar ones are good, every design has it's place and most of bad press comes when wrong product is used to wrong job.
As for Savonius being cutting edge, well, it was invented at 1922 by one Finnish guy, similar kind of things have been sketched and tested as early as 1616 according to Wiki page.
Anyway that has not much use to you, just thing that are nice to know.
This might be useful for you, mostly one graph at realtively early on document, it shows efficiency curves of different wind turbines, so you can see how different wind strength are where different designs do work, choice between 2 and 3 blade design should be easier with that, imo.
http://www.2004ewec.info/files/23_14...ucmenet_01.pdf