The Power of the Sun.

Thanks, just what I wanted. There is no boat yet, but there could be, if I find the time.

Suggest trying to google "solar insolation map world" or substitute your location for world. Lots of good info available.

You could try out this site.

eosweb.larc.nasa.gov./sse

I may be wrong, but I don't think solar intensity matters a great deal for sizing PV panels. If it's sunny, a 75 watt PV panel will put out about 75 watts. Doesn't make a huge difference where/when. There are some nuances due to temperature, etc that will effect power output, and those can be seen in the curves for a particular PV panel.

If you are calculating heat from a solar hot water panel, then where/when will probably make more of a difference.

Google PV panel sizing calculation, or something like that and see what you find.

Here is just one place to get information and help on sizing your PV system:

http://www.backwoodssolar.com/

Over on the left side of the page, use the pull down menu's and click to find good info.

Good luck.