Abandoned vessels can pose a threat to the environment, which I think is a major point. If they go adrift, they can pose a navigational hazard to deep-sea vessels and can cause the port to be shut down to avoid a bigger accident, as was described in the BC Ferries case.
It's great that we're looking at derelict vessels, but it all starts with preventing vessels from becoming derelicts. If we look at British Columbia, it's predominantly in the registration systems and the insurance requirements for vessels, from small recreational vessels to the larger vessels. Even the larger government vessels, BC Ferries or chip barges, are being sold to owners who don't have the means to support them but can pick them up, and then the previous owner basically absolves himself from responsibility and the new owner can't fulfill the requirements.