Sorry you were a victim. I'm lucky, naive, or both.
I looked at locks when I bought a spare tire carrier and didn't get one
because none of them looked capable of stopping a thief, only of being a
nuisance to me.
I have a lock on the trailer coupling handle that looks pretty sturdy. It
also keeps the handle from releasing, which gives me comfort when towing the
trailer.
One tip that has been helpful to me: I always use the same tow vehicle, so I
have a fanny pack for the boat ignition key, trailer lock/trailer hitch key,
spare handkerchief and wallet. The wallet is designed for a fishing
license - it has a lace to hang around your neck, several window pockets
(fishing, boat, trailer license) a zipper pouch for change, and a billfold.
I keep it in the tow vehicle except when boating, then I put my car keys in
it and stow it under the instrument panel of my boat.
I keep an assortment of change and bills in the wallet, since I don't always
have much money with me. If anything happens, I'll have change for a phone
call and soda pop, and a few bucks for a sandwich.
Keeping the car keys in the pack while boating prevents the chance of
getting the electronic lock/alarm on the car key ring from getting wet. I
usually wade into knee deep water to launch/recover, and once had the keys
in my swim shorts while water skiing.

"Gary Warner" wrote in message
...

I once had my boat broken into and another time had the jack
stolen off my trailer. Both of these occurred at a public boat ramp
in the Boston area. But each happened when I left things there
overnight. A very stupid decision on my part...but I did not
have a garage or land (just an apartment).

ANYWAY, so now we're building our trailer and getting
ready to (HOPEFULLY!) start using this boat soon. I'm
quite certain we will never leave the boat anywhere
by itself. But the trailer is a different situation.

Do others have stories and/or products they use to
insure that the trailer is not messed with? I know
of the devices that go into the ball socket. It
trailer theft common?

Ok, more specific question: We just made the spare
tire holder. The tire currently is just on there with
two lug nuts. It would be SO easy for someone to
take it. I could use a cable and lock it to the frame.

Has anyone use locking lug nuts?

Anyway, not too concise - sorry. Just thinking out loud
so any comments or suggestions welcome.

Thanks,
Gary