I'm changing my boat insurance and the new company require an anti-theft device to be fitted even though my boat is stored in a locked garage.  I quite liked that this has an audible alarm, so if anyone breaks into the garage and is fiddling with it I'll hear them, or the dog will.  Also when at the boat ramp this lock can be left on the trailer while using it, whereas if I use a wheel clamp it has to be removed from the trailer before going to get the boat.  Or am I better off just sticking to an SAS wheel clamp and accepting it's going to take a few minutes to get it on or off?