Sorry Meridian, it didn't work as planned. I have tried the code but the facility neither showing on sea or land.
Originally, I believe the best way to implement this is, the first facility you construct when you build a new base. The airlock is either land or sea type, then using provideBaseFunc from the airlock to distinguished either land or sea facilities.
However, this said, the only undersea base facility I am concentrating on having this distinguishing feature is sea pen.
If you can code the craft to have "Usebasefunc" like the craft will only use the service the hanger provides, this will serve me
all I need. If the coding is not too much. With this, I can make submarine to use only that hanger or subpen. If the craft is transfer between bases, it will only able to use the hanger with Usebasefunc.
I won't ask anything else from you, if you can just give me this feature and solve the vaportrail problem.