Ship sim extremes and the proffesional one are not focused on realism.
Shipsim is just a arcady creation that they could make out of their pro sim with almost no effort.
Their pro one is focused on full mission bridge simulation, Training young officers how to handle and command a ship, where the controls are at, and how to operate, NOT how to sail a ship. (and yes I have used both of them and Kongsbergs simulator, which is similair)
They do not give a realistic representation. As of now, I do not know a game with advanced hydrodynamics. WoWs gave it their swing wich gives a bit of a feeling. I have to try the vbs one yet, their vids are promising, but I do not expect much.
Ship sim is very dead at the moment. No support what soever. servers are down. no one active on the forum. World ship simulator is super arcady, nautissim is close to ship sim (thats the vstep pro one) and not for sale for private people.
You can give the people at
http://www.transas.com/products/simulation a try. I have heard they helped people in the past. but have your $$$$.$$ ready (yes four infront atleast)
For the rest? we only can hope,
(I am a Naval Architect, with experience on ships)