My concentric pole concept wouldn't have had this problem. Just sayin'

 

My concentric pole concept wouldn't have had this problem. Just sayin'

Even if I accidentally drilled a hole in the bucket???

 

Even if I accidentally drilled a hole in the bucket???

Yup

 

Yup

I get the idea of concentric poles with a weight at the bottom and a float at the top, but if I punctured the float it's going down at least 3 feet - the height of the lighthouse. Unless I don't get the idea. Perhaps the problem you're talking about - the one I wouldn't have - is that it wouldn't sink out of sight.

I'm averse to the pond bottom having anything to do with keeping the lighthouse vertical. I can't see it, can't touch it, or change it. It's a big unknown.

I'm either going to get a new bucket and give this another go, or maybe do another floatation scheme. Like an "X" about 6 feet across with smaller floats at each tip, but I would want to come up with something where those 4 floats wouldn't be very noticeable. Suggest something.

 

How about this? A fake rock well cover (36"x36"x9", 12 lbs), a 1-gal water bottle strapped under the rock at each corner. A weight, like 1 brick, suspended several feet under the thing, and attached with 4 tethers at each corner. The tethers would be adjustable in length at their attach points, so I could adjust the length of each to attain vertical alignment of the lighthouse. The lighthouse would mount to a small circular platform at the center of the rock. I think I would have to experiment to find the center of mass and/or floatation and mount the lighthouse there. That would be my course alignment adjustment; adjusting the length of the tethers would be the fine adjustment. I'd have to drill a hole in the rock so it's trapped air would not add to the float power.