The cradle runs on 5 rails.Its hauled by a double drum winch,one line hauls up the others hauls back down.1'' line 8 parts on the main 7/8'' on the haulback 6 parts .The vessel is measured by some very talent ship guys to get the hull shape right .blocking is then set to conform to the hull.The cradle is lowered to acomadate the the vessels draught ,its floated in blocks adjusted and winched up.Usually they are repaired and relaunched,this boat was a deralict in danger of sinking.The company I was working for was awarded a contract by the government to decommission and dispose of this once proud ship.Lots of hazmat work and a bunch of plasma and torch work.