I like the salvage
claim idea, of course that has to apply to every (unmanned) boat that gets rescued, and for a settlement to be agreed (to release the boat / claim) to include not only a cash figure but also a waiver on any future damages claim......and for those that are insured would also top up the coffers (even if they settled on less than full commercial
- or only at beer
donation level, or actual beer!)......or how about doing the rescuing end of the work only via a limited company (or a sister charity?) that has no assets of it's own (only leased / borrowed from the parent Charity) - so they can go broke in the face of a claim, which should put off a few folks (and lawyers!) looking to sue.