Well yeah, they were only minutes away at the point they lost power, there was very little time to do anything at all, that's why I asked. Personally I can't really imagine anyone holding it against them for using the 'signal that's for other ships' 'incorrectly' or 'against protocol' in such a situation. I think the comments speculating that the horn is either purely or in some way (e.g. solenoid) dependent on electricity is more likely the answer. I think a reasonable human in that situation who knows what's going on (that's why I mentioned that they apparently were able to radio/however they mayday that there's an issue) is going to do whatever they can, including use the horn wrong.