putting

Our 30-year old aluminum diesel tank has no access or clean-out hatches. It is an 80 gallon built-in ... literally, it extends under cabinetry and (partial) bulkheads. I can see how to cut access hatches in the teak (plywood) sole and make that work well. What I am much less sure about...

I'm thinking of putting my 35' 1983 Ericson Mark 3 on the grid to clean the bottom. Have I anything to worry about other than attaching the ropes etc.? Would appreciate some replies from others who have done this.