Wind Generator placement ???

SimonV · #1 (**permalink**) 10-15-2010

I have my radar mounted at the back of the boat on a pole that is also my o/b motor crane. what I would like to do is mount the wind generator over the radar dome, rather than put a second pole on the port side. Would this cause any problems to the radar, the cable is shielded

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Bene505 · #2 (**permalink**) 10-15-2010

Wind generators create a lot of vibration, not sure I'd want one shaking my radar.

Also, that seems to be really high up. It's going to add a lot of heeling when you're out sailing.

But what do I know, I'm still installing our wind generator.

Regards,
Brad

PBzeer · #3 (**permalink**) 10-15-2010

Like Brad, I would be concerned about the vibration. Placing the wind gen on the other side would add symmetry, visually and physically.

SimonV · #4 (**permalink**) 10-15-2010

Hey Brad, the generator weighs 13lbs and I guess 4lbs for the extra s/s short pole to put it over the radar. Also it may impact on the movement of the wind vane.

sailingdog · #5 (**permalink**) 10-15-2010

Aside from the vibration issue, which isn't good for the radome, how tall is the pole that you'd be mounting the wind gen on and how would you attach it to the radar pole. I can't see of any way of securing a second post that above the radome that wouldn't interfere with the radome's operation, since it appears the radome is mounted atop the existing pole, rather than on a bracket attached to the side of the existing pole.

What might make more sense, is replacing the existing pole with a taller one and then mounting the wind gen on top of it, and mounting the radome on a mast-mount on the forward side of the pole, low enough that it is clear of the blades.

SimonV · #6 (**permalink**) 10-15-2010

Quote:

Originally Posted by sailingdog

Aside from the vibration issue, which isn't good for the radome, how tall is the pole that you'd be mounting the wind gen on and how would you attach it to the radar pole. I can't see of any way of securing a second post that above the radome that wouldn't interfere with the radome's operation, since it appears the radome is mounted atop the existing pole, rather than on a bracket attached to the side of the existing pole.

What might make more sense, is replacing the existing pole with a taller one and then mounting the wind gen on top of it, and mounting the radome on a mast-mount on the forward side of the pole, low enough that it is clear of the blades.

Hi Dan, that is what I would like to do but leaving the radar where it is and having a new section of 3' x 2" S/S tube welded to the existing pole and bent like a J .

sailingdog · #7 (**permalink**) 10-15-2010

I think going with a single piece pole would be better. Welds are more likely to fail due to corrosion issues than a single piece pole would be.

Bene505 · #8 (**permalink**) 10-15-2010

Quote:

Originally Posted by SimonV

Hey Brad, the generator weighs 13lbs and I guess 4lbs for the extra s/s short pole to put it over the radar. Also it may impact on the movement of the wind vane.

It's not the weight, it's the wind area. When spinning, the blades have the wind resistance of the entire swept area of the blades. So if it has a 3.5 foot blade radius ([edit] 7 foot diameter), the wind resistance would be the same as a sheet of plywood. That's a lot to have 17 feet above the water. Even without the vibration and the welds that Dan mentions, it makes more sense to use a separate (and shorter) pole.

If you do use a separate & shorter pole, it will likely interfere with the vane on a narrow wind angle. This may be a good case for one of those annoying, noisy-but small wind generators mounted at just the right height.

Maybe it makes sense to back-up a bit on your requirements. Are you looking for charging mostly at anchor or while underway? Have you thought about putting solar atop your bimini? And there are more basic things like making an energy budget.

Regards,
Brad

sailingdog · #9 (**permalink**) 10-15-2010

Brad—

a 3.5' radius is a 7' diameter..

A 6' diameter windgen has 28.27 sq. ft of effective surface area, a 7' diameter windgen has 38.48 sq. ft. of effective surface area.

Keeping the windgen high enough so the blades are not a hazard to the captain and crew is a very good idea. You can get chopped up pretty badly in higher winds by the blades.

Bene505 · #10 (**permalink**) 10-15-2010

Quote:

Originally Posted by sailingdog

Brad—

a 3.5' radius is a 7' diameter..

A 6' diameter windgen has 28.27 sq. ft of effective surface area, a 7' diameter windgen has 38.48 sq. ft. of effective surface area.

Keeping the windgen high enough so the blades are not a hazard to the captain and crew is a very good idea. You can get chopped up pretty badly in higher winds by the blades.

Yes, make that 7 foot diameter. And "almost as big as a sheet of plywood".

I'm not advocating anything lower than what you can reach up to, to tie off the blades.

Regards,
Brad