If you are planing on doing this at the
dock, I'd be inclined to hire someone familiar with polishing
fuel and tank
cleaning. The downside of DYI is contaminating your marina and surrounding waters which shouldn't cost more than $3-400K to clean up plus all the miriad of
government oversight, local, state and feds. If you are in an 'environmentally sensitive' area double the cost and if there is a Seminole Indian settlement within 100 miles, it will become an Environmental Justice Site and the cost just doubled again. Good luck with your tank
cleaning project!! Phil