Larry W4CSC wrote:

However, on ships, to reduce the voltage to ground reducing shock
hazards on 120V power systems, there IS a 60-0-60 system with a
center-tap-grounded power system. I used to serve on old Navy ships
that had this system. Not sure if they still use it on new ships,
now.

There was never a "60-0-60 system" on ships. Nearly every ship generates
3-phase power and for hotel services requiring 120VAC the phase
transformers are wired in wye-delta providing 3 conductors each of 120
volts between any two conductors. The voltage measured to ground would
be either about 87 volts or 70 volts depending on the phase which is
measured against the ship's ground.

When 120/208 power is required the phase transformers are wired in
delta-wye with a 4th neutral conductor connected to physical ground. Any
conductor measured to ground would deliver 120 volts single phase. The
voltage between conductors is 208 volts 3-phase. This is not commonly
supplied to "hotel" services as it is preferable to reduce shock hazard
via the lack of a grounded neutral and to avoid using the hull as a
current carrying ground.

Rick