Air X
I put an Air-X on our last boat and only used it for a season before we sold the boat. The Air-X puts out a lot of amps if the wind is 15 knots or better. We cruised the Bahamas and the wind seemed to always be 20 or better. Lots of free amp-hours.It made a bit of noise, but you get used to it. It was on the stern of the boat and we slept in the aft berth. In a storm with 30-35 knot winds it was nice to turn the switch off and slow it down. If left on in a big blow, the batteries fully charge and the unit will cycle on and off. It uses a little current to apply the brake and this causes the battery to go accept a charge after 4 or 5 minutes and it turns the generator back on for 30 seconds and on and on.I notice that you have the 420. On ours the diesel genset does a good job of batteries, hot water, etc. As long as the boom is on the 420, you will have to mount the wind generator way off the back of the boat. We have davits there and didn't want to build an arch to do everything.Bill