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most definitely useful. in winter it helps about 60-70% with power. we get a lot of wind in the winter. and when it storms at night it can generate a lot of power. in our open field it would be all we needed most of the year. but that is over 100 yards away so wire cables would have to much resistance in them. eventually we will get it another 20 feet higher above the tree line.

oh.
as always I'm considering it for my boat.
I could put one on top of the mast.

they make wind turbines specially for boats :)

oh yeah..
but the word 'marine' is a code for "costs ten times as much"

of course lol...