Anybody ever try any preventative measures to keep beaver from setting up inside a boathouse?
Ultra sonic?
Security light?
Thanks
Jim

What do you mean?

Is he caching food under the walkways? (very common here)
or
Building a lodge under an overhang?

Not sure if chain link fence would help you.

Could use a lil more info.

Complete lodge inside the boathouse. I have now trapped this same boathouse for the 3rd time in about 6 years. The lake has a rocky shoreline with mainly sand bottom, hard for the beaver to make lodges. The owner floats there dock inside the boathouse for the winter and the beaver set-up against the back of the boathouse. Previously i had used 1x1 wire to close up the back of the boathouse because the beaver would build right up underneath, now they just build up against the wire out into the boathouse.
Have a full feedbed and lodge. Will try and post some pictures.
Everytime I trap them out I completely remove every stick, place is completely cleaned but new beavers seem to move in every couple of years and set-up shop again.
There is power there so I was thinking of trying some sort of deterient, a security light with a motion detector, an ultrasonic device?

That's crazy. I'd love to see some pictures. I've not heard of beaver messing with a boat house.

Beaver get in the boathouses here every year too, under the docks etc. Got one to work on in a few days. Seems like a lot of work, expensive, to try deter them or fencing it off. You can kind of figure where they are going, even on bedrock or see a run, sometimes an opening in the feed. I usually just put cages the bottom as it requires no real finesse, just set them in. Beaver make dens then otter come in and use them for a toilet, which is attractive. LOL.

Leave 'em alone - the poor things - they have "rights" ya' know...
That's just crazy - never seen anything like THAT before!

Ya' might build a new boathouse and save that one for some beaver "seed"...
They can show up in some peculiar places.

Wow, that is a glorious mess! Did those beavers have a building permit? I would love to have an interesting challenging project like this.

After you remove the lodge and feedbed and everything is back to normal, could you build a framework and install insulators for electric fence? You said that you have electricity there. If you use a perimeter or whatever is appropriate for the house and add 3-4 strands of electric fence above water of course, it may prevent the problem. You can build in a switch to control the system,

I have done this successfully for raccoons, geese, deer, dogs, and other critters. I believe that it could be done here to solve the problem. It would require minimal maintenance. If you want to discuss this further, contact me.

Best wishes.

Maybe try a 'beaver float' set, using a 330 BG.

I tried some yote gland lure in some pee on a job. Gave the area a good squirt and the beaver moved out. May work for you.