What About That Thing? (More Amp Hours, Part 1)

Posted by John

Part way up the mizzen mast, just below the spreaders, is a curious “L” bracket thing. It was on the boat when we bought it.

phone photo L bracket

No one has ever questioned it, but I can imagine somebody wondering what it is. It’s a mount for a wind generator, and we’re finally putting one up there to supplement the electrical power produced by the solar panels.

To me, when someone mentions wind generator, I immediately think of a small, wind-powered turbine used to generate electricity. I probably first became aware of such a device in the 1970’s when I noticed ads for them appearing in certain magazines. I had a friend at the time who looked at the picture and the price, and said he could build one for nothing from junk he had laying around. I told him I bet he couldn’t. We moved on to the next thing, but I’ve remembered the exchange ever since.

Preparing for mast and rigging removal
Preparing for mast and rigging removal

More recently, I’ve learned that not everyone conjures up the same image. If you mention the term “Wind Generator” to some people, and then point out the bracket located behind the mainsail, they might, without a lot of thought, jump immediately to the conclusion that it is a device that somehow fills in for the natural wind in its absence. Like a fan—a wind maker—aimed at the sail to push the boat along. I can see why they might make that assumption even though something about it doesn’t seem quite right. Newton even made up a law about it.

Our main source of day-to-day electrical power is the solar panels mounted over the cockpit. When we use the boat for a week or two on summer vacation, whatever power we use onboard at night is usually easily replaced the next day by the solar panels. I suppose it helps that summer nights are short, and we usually sleep through the dark part. But soon we will be moving onto the boat full time, and power demand will increase. The thought of sailing down the coast at night, potentially in fog, with lights, radio, radar and whatever else turned on, concerns me with the unrealistic demand that might put on the solar panels the following day. I’d rather not have to rely solely on the engine’s alternator when the solar panels aren’t enough. With that in mind, we put a wind turbine generator on the wish list. Installation should be easy because the mount is already there.

When we bought our boat it also had a tow generator mounted on the stern rail. The concept is similar to a wind generator, except that in place of turbine blades attached to the generator’s rotating shaft, there is a long rope with a propeller on the other end. While underway, the rope and propeller are dragged behind the boat, it all winds up and turns the shaft of the generator. As long as the boat is moving at normal cruising speed, and a large fish doesn’t mistake the towed propeller for food, it will produce power day and night. We never found the propeller that was supposedly on the boat somewhere, and the actual generator was so corroded and frozen up, I gave up trying to salvage it.

I personally like the idea of a prop shaft generator. I’ve seen pictures of them on cruising boats, but never talked to anyone who actually uses one. It’s a lot like the tow generator except that instead of dragging a propeller on a rope, you use the one you already have in the boat. An alternator is driven by belt from the freely spinning propeller shaft when the boat is moving under sail (doesn’t work with feathering props). When I hear our shaft turning, I can’t help but think of free energy going to waste. We have enough space in the bilge. I know it’s been done on a Westsail 42 before.

When I asked a marine installer if he’d ever seen a shaft generator, he said he couldn’t recommend it, saying that keeping the necessary tension on the belt puts sideways stress on the shaft coupling and transmission, and can cause excessive wear and misalignment. Last year, when we replaced our stuffing box and cutlass bearing, I momentarily considered putting it all back together with a pulley and belt around the shaft, just in case we decided to try a shaft generator in the future. But I didn’t do it, and we’re not planning to pull the shaft out again anytime soon.

Looking around online, I’ve seen many variations on the towing or shaft generator idea for getting electrical power from boat motion. But in actuality, we spend a lot more time with the boat not moving, than when it is. We want power when anchored, too. Just because the wind isn’t being used to push us along doesn’t mean it shouldn’t be working for us in the form of generating electricity. A wind generator installed on the existing unused mount was therefore the choice for a means to supplement the solar panels. However, the decision was not made without consideration for noise, vibration, and wildly spinning blades snagging lines and ripping sails.

Allotted work area for the mizzen mast
Allotted work area for the mizzen mast
Our first close look at the "L" bracket
Our first close look at the “L” bracket

Last year, with the boat in the yard and the masts off for nine weeks, we got our first close-up look at the mizzen mount bracket. For ten years we’d gazed up at it, studied it from afar, but never went up to look because we only had one halyard on the mizzen and nobody wanted to be hauled up there without a safety line. When the masts came down, we took the mounting bracket home and cleaned it up and repainted it. After making measurements and comparing online images, we determined that of all the wind generator models we had previously considered, there was only one that would fit the existing bracket. It was the Ampair 100, made in England.


Due to size and shape, any other model of generator would require a different bracket, possibly even in a different location. That would require much more work, time and rethinking of the whole thing.

On the last weekend in June, with the boat scheduled to go back into the water the next week, and the masts going back on a day or so after that, we scrambled to finish up everything that needed doing before launching. This included getting the new wind generator wiring in now, while it was easy. It would be much more difficult if we waited until later, after mast reinstallation.

Pull rope for wind generator wires
Pull rope for wind generator wires

Running the wires was harder than we thought, and would’ve been nearly impossible with the mast stepped on the boat. For a small mast (32 ft), it has a lot of wires crammed into a PVC conduit inside it. The conduit was already jammed with wiring for the radar, AIS antenna, a cockpit floodlight and mast-top emergency strobe. To that, we were adding wiring for another light, a loudhailer, and the future wind generator.

The masts and the boat were in two different boatyards in Port Townsend, at opposite ends of town. Time could be dedicated to either the mast or the boat, but we couldn’t work on both at the same time without packing up our tools and getting in the car. We spent most of a very hot, sun-scorching day trying to pull a 10 gauge, two-conductor cable through a hole below the mounting bracket, into the PVC pipe, and out the bottom of the mast. We gave up, stripped the outer jacket off the cable, and tried again. We gave up again, defeated. Then we set out in search of advice. The advice we found was to use a larger pull rope than the string we had, and use copious amounts of Wire Lube. We also decided to use smaller 12 gauge wire, instead of the 10. I’m not sure which of those things made the biggest difference, but something worked. I’m pretty sure it was the lube.

The difficulty with the wires cost us a day, and prevented us from finishing up the boat itself. We were forced to reschedule our launch time. With Fourth of July vacations being taken, and high demand for the travel lifts, our next opportunity wouldn’t be until July 2nd. At some point I remembered that I actually had a job to go to, and physical deadlines for projects at work. Mentally, I realized, I had already made the transition to cruising.

With the generator wiring finally in place, the masts back on the boat, and three brand new halyards installed on the mizzen, I was already thinking about a future sunny day in Mexico, hauling a wind generator up to the mounting bracket and plugging it into the wires that had been so frustrating to install. But then, we learned that Ampair had been bought by another company, and the Ampair 100 was no longer being made.

The thought of starting over with a different model and different bracket was not only discouraging, but wasn’t going to happen. We had other problems that were more pressing, so the wind generator project was put on hold, along with, ultimately, the idea of being in Mexico by Christmas. We missed our planned late summer departure.

Over the winter we learned of two Ampair 100’s in a warehouse in Renton (near Seattle), at the ABS Alaskan company. We periodically checked the website to make sure they were still available, and thought that if the opportunity came up, and we had some money, we should grab one before they were all gone. The speculation was that the new company, Seamap, primarily involved in deep water oil production technology, would start manufacturing them again, but it was hard to say when, or if, that would be. The more time that passed, the more risky that option seemed to be. So, in late April, we called ABS Alaskan and bought one of the Ampairs.

Our new wind gen out of the box
Our new wind gen out of the box

Down the road, in Part 2, we’ll tell how it all worked out. But first, we have to figure out how to get our unexpectedly heavy wind generator up the mast and onto that “L” bracket thing.