Right, but this is purpose speced for long-term stationary operation. FPSOs and other ships like that DO operate in that manner. Naval ships do, too. The reason other ships don't is that they're in relatively constant motion, and even those are switching to use shore power and aux power, since they have switched to more expensive fuel (diesel vs. bunker), fuel has gone up in price (what, 3x?), and environmental regulations apply.

Big marine engines are crazy (like 100k horsepower?), but that's not what you would use for this purpose.