Yes, agree. I did take the OP to mean that they had run out of water (or were worried that they shortly would) but I accept that you could read it that they just wanted to tack. And in that case they would indeed have no right to ask to tack if racing.
That is true, but much abused. Boats merely in a bad position often call for water. You have to give way, and complain later.
Other boats and commercial shipping are very much obstructions. The fact that they move is nothing to do with it, apart from the obligations of colregs. Tactics need to be modified to take them into account. Failure to spot the arrival of a tanker when racing in Cowes can ruin your race. A sailing cruiser is no different apart from size. You can’t assume they'll get out of your way. How many more boats could they have to avoid? Better by far to stick to the letter of colregs. Everyone knows where they are then. It would be good manners for cruising sailors to avoid obvious start areas by changing course early. But other than that, for Gods sake stand on if that is your right. Or we'll all get in a mess.Surely the racer had the option to drop back and cross jimmys stern ? In which case putting the engine on was a courtesy, but not something required to prevent the racer going aground as that option was always available, and failure to take it would be the race skippers own choice and own fault.
Be different if he had screwed up and got himself into a pickle hecouldnt get out of but it doesn't appear to be the case. The problem the race skipper was calling for water for was so he wouldnt lose time or position, in which case, tough shit
I would have thought part of racing is to to take into account other traffic and sail your course to avoid and go round them, treating them as moving obstructions the racer can have no control over.
