Hi Steve,
I have two 105 Watt solar panels fitted on an arch over the rear. The arch is mounted on the pushpit rather than having a replacement pushpit built or fitting a purpose built arch directly to the deck. This was a more or less standard part made by a local (to me in St. Cyprien, France) supplier. I was dubious about the strength and stiffness of this but it was a low cost alternative and so far has performed all right. It is a bit wobbly and I have not been in any force 12's yet however.
Two 105 Watt solar panels plus a wind generator made me completely autonomous doing continuous cruising in the Med in summer.
It is not enough for crossing the Atlantic in January if, like me, you consume about 6 amps per hour continuously. This is :
- Nav and auto-pilot running full time consisting of : Garmin 4008 chart plotter, Garmin GHP12 auto-pilot, Garmin tri-data unit, VHF.
We had to turn the fridge off. There is nothing to keep cold after the first week anyway.
We had to run the motor for at least one hour every day after the first couple of days. This is very unsatisfactory as motor charging is very inefficient and costly in diesel. I don't have a "smart" charger and the diesel only charges significantly during the first hour. After that, charging falls away to a trickle no matter what the battery amp-hour level.
This is also true for the solar panels to a certain extent. The regulator switched the charging off when the voltage indicator showed around 13 volts but the amp-hour indicator showed that the batteries were still at -70 Amp-hours. The only way to get it to switch on again was to draw down the battery by switching the fridge on. This dropped the voltage and the charger would switch on again for a while. I have not worked out any other way to get round this yet.
For trans-atlantic useage, I would consider a water generator like a Wattsea. I haven't worked out yet how to mount one with the very nice but in some ways impractical wide swim platform.