"And have you SEEN what water spray does to a capacitative touch screen?"
Have you seen what spray does to anything electronic? Thats why they electronic kit is protected from the elements.
I work for a company which makes ship control systems and we have a combination of touch screen and physical controls
Modern ship control systems are a bit more than port/starboard/aft/forward. They are more like aircraft fly by wire systems where you tell it where you want to go and it works out the optimum path. While in theory you could do this using pushbutton technology (which are also prone to ocean spray), it would not allow the optimal control of your system.