<Peter wrote: ....While bow/stern thrusters and electronic navigation systems have helped, running a 70-footer is not trivial........> We have a good friend that operates his liveaboard 96' tug, Lakota, almost daily with his crew. The crew consist of Becky, his wife, and Veronica, their 3 month old baby. No bow/stern thruster and little of the new fangled electronics. They are soon running down to Trinidad, ~500 miles, to tow an old 3 masted sailing ship back to turn it into a dive site in the BVI. Take a look at it http://tinyurl.com/25rdrx It all depends on what you are used to and how much experience you have as to what is small, big, bigger and "too big". In some case you will begin to fall under various regulations of staffing levels whether it is a private use boat or commercial before you reach the limits of ones own abilities. I have run without any crew sailboats to 71 ft and power to 80. No big thing, IMHO. Planning and think ahead proactive actions are required. As always YMMV.... Cheers Dave & Nancy Swan Song Roughwater 58 Caribbean Cruise '07