Hi Myles,
I have to say I'm with you on regen. Basically I'd want a boat with an LWL that allowed cruise at 6 knots or more and personally I'd rather have a folding prop for most situations, other than say long tacks crossing oceans, in which case I think a regen prop is worthwhile.
In terms of turning a bigger prop for regen I've often wondered about the Gori Overdrive prop for experimentation. My only experience of these is crossing Biscay last year in my friend's Discovery 58. Basically you have a choice of different pitch as Nigel Calder explains:
http://www.sailmagazine.com/diy/engines/two-speed-propeller/
My favourite solution is solar and were solar cloth sails, biminis, and spray dodgers more affordable they would be my priorities. But to me fixed solar is to me affordable and the best current solution.
And here's the rub in my case. My small 60W (2 x30 in series) solar 'array' gives on average, at my 55 North Latitude, 5 West in the summer months, 2.5 times panel rating = 150Wh per day, which is just about enough to run my 4 G router. Max I've seen is 5 x panel rating in summer and worst about 1 x, using an MPPT of course.
As some of you know I opted for minimal batteries (2 in series) in part due to cost but also due to lack of space and wanting weight in the right area and still being able to get access to my stern PSS shaft seal. So with less batteries and solar than most the logical solution was a small backup generator. I opted for the 1kVA Honda as the 2kVA was half as much again in cost and the rated outputs (they use the same engine just at different rpm) are 900W vs 1600W. Also as I have max 1,100W of chargers for my propulsion lithium bank it made sense to buy the smaller one especially as I only need about 1000W battery power to cruise at 4 knots in calm conditions.
Anyway my point is, to match my solar harvest per day I need only run my generator for only 10 minutes or so. To me that's not so inconvenient and the little Honda with light use has likely (from experience using Honda engines of all kinds) will last 20 years and the costs over time compared to batteries, solar and wind is negligible. Of course that's economic logic and there are reasons to look to renewables for boats simply because of the silence and simplicity of e.g. solar.
John R
