The first thing is to put out a mayday. This may be your only chance to get a message out. There is immediate danger to life and/or property so the mayday is appropiate. At this point the mayday should be informational and include position speed and direction of travel. State your intentions (check for leaks, etc) and let someone know when your next contact will be. Don't be late getting back to your contact - they will be sending help if they do not hear from you. i don't think it matters if there is a gale, 300 miles out, or 10 miles out - the danger is aparant and real so the mayday is the way to go.