Lodown,
Its a good question. Complicated answer though. In training levels there is some sim work but its real basic stuff. There are no real "off the showroom floor" ships so its hard to come up with generic models for sims which would 'feel' anything like the real thing but its an ongoing debate.
Marine Pilots (the folks who pilot ships in and out of most ports / canals etc) use sims to practice tight / slow manouvers and emergency recovery manouvers for thier particular local conditions.
Sims are used to test a port or a confined area if there are intentions to push the margins, eg: to find out if 'x' size / type vessel can safely navigate at or thru 'x' location. We would ask a training org to write a sim for the port in question, then introduce the vessel characteristics we need and when its all ready, we'll play with it using different weather / sea conditions to see what works and what doesn't so we can whip up an SOP or use it to convince authourities to let us give it a bash.
Of course, sims are also used to test ship designs and mods.
But as far as jo bloggs the deck officer goes, not much sim time compared to aviation.