Hello Julian,
Ship Simulator Professional is derived from Ship Simulator 2006, not 2008. It had indeed a serial interface.
Ship Simulator Pro 2008 has not been distributed and is in fact the original Nautis software, derived from 2008 with rather large improvements in the software, but still with the 2008 arcade parameters of the ship dynamics. I imagine you were part of the initial group of testers/moderators (or some family member perhaps?). Adding a bow thruster to a ship is rather easy, but the 2008 water resistances of the ships are not aligned, as if the water viscosity was not only specific to each ship but also much too high. Because of this, masses, mass moments of inertia and thrusts are inconsistent to achieve the guessed ship movements.
Nevertheless, it was eventually assumed that the core program was good enough to be developed and later marketed to become a first rate bridge simulator, no longer as a game. That is why there was no Ship Simulator Pro 2008, and it evolved under the name Nautis after major changes as you can imagine, but not so much graphically due to the video cards limitations at that time.
Simultaneously, Ship Simulator Extremes was developed, while sharing evidently common development features, but focused on the gameplay (de gustibus non disputandum est), adjusting and testing/checking the hydrodynamics of the ships as a model, but disallowing any possibility to compete with Nautis : No wind forces, no tidal streams, no elaborate shallow waters effects, no.. no.. no... no serial I/O. Schade.
As you see, there are not many possibilities to implement an NMEA interface to SSE, buying VStep Nautis (easy and not cheap but worth its price) is one, deriving by yourself an NMEA interface from the multiplayer connection if such thing is possible (I think so, but it would be uneasy).
There is also vShip (http://marinesimulation.com/vship/), who boasts "unmatched visual realism" and "advanced physics simulation", "NMEA, AIS, ECDIS, GPX compatible", perhaps pricey and limited, eventually other simulators.
If your question is about some nautical happening demo, you should investigate the issue with VStep, I can imagine that advertising Nautis with a boat/nautical equipment could be solved satisfactorily.
Anyway, good luck
Luc
