EL-
Don't think that I don't feel for you, I have had the same thing happen to me. I had a new 8hp Merc stolen out of my apartment after I had saved for years to get it. It had 2 hours on it and being a poor student, I had no insurance.

Since you are locked into a lease, you might call a couple of the marinas over there and ask if there is some kind of concealed alarm system you could wire up. You can't be the first person this has happened to. It may even help out on your insurance costs.

Another thought is with all of the storage facilities popping up all over the place, maybe there is one close to your favorite launch area that you could keep it in a locked garage. I don't know how much they run a month, but it may give you peace of mind and you could sleep at night. It might be well worth the money for awhile til you can get into another, more secure area. That may help on the insurance premiums also.
The only way that you can really keep them from stealing it again is for them not to be able to see it.