Its a favourite tactic, for ribs in "unsecure" storage, to just cut the engines off complete with a chunk of transom, and leave the boat wrecked. That's more your targeting gang, rather than the local tealeaf.
There was / is a similar spate of thefts around the South Coast Southampton - Hastings area on an almost industrial scale.
It was said to be a well known Eastern European gang, indeed the police on ' Project Kraken ' asked for a lookout for a certain car and reg no, this was thought to be the gangs' recce operative sizing up targets.