Not to muddy the waters but, the latest ABYC Standards includes a major rewrite to E-11 and it has this to say about RCBOs, RCDs, GFCIs, etc.:
11.11 GROUND FAULT PROTECTION – AC SYSTEMS
11.11.1 An Equipment
Leakage Circuit Interrupter (ELCI) shall be installed with or in addition to the
main shore power disconnect circuit breaker(s) or at the additional overcurrent protection as required by E-
188.8.131.52.3 whichever is closer to the shore power connection.
184.108.40.206 This device shall meet the requirements of UL 1053 Standard for Safety
Sensing and Relaying Equipment and the requirements of UL 943 Ground Fault Circuit Interrupters with the
exception of trip level and trip time. Trip level shall be a maximum of 30mA. The trip time shall be a
maximum of 100ms.
NOTE: Trip levels of less than 30ma and times of less than 100ms may result in nuisance trips in
220.127.116.11 The ELCI shall be readily accessible.
11.11.2 If installed, a ground fault protector (GFP) shall only be used to protect equipment.
NOTE: A ground fault circuit interrupter (GFCI) may be used on single
phase AC circuits to provide
additional protection for personnel and equipment.
11.11.3 GFCI breakers shall meet the requirements of Underwriters Laboratories standard UL 943,
Ground Fault Circuit Interrupters, and the requirements of UL 489, Molded Case Circuit Protectors for Circuit
11.11.4 GFCI breakers may be installed as panelboard feeder breakers to protect all associated
circuits or in individual branch circuits.
11.11.5 Single-pole GFCI breakers shall only be used if:
18.104.22.168 the single
phase 120 volt system has a polarity indicator, or
22.214.171.124 the system uses either a transformer, or
126.96.36.199 the system is 120/240 volts.
11.11.6 GFCI receptacle devices shall meet the requirements of Underwriters Laboratories' standard UL
943, Ground Fault Circuit Interrupters, and the requirements of UL 498, Electrical Attachment Plugs and
11.11.7 GFCI receptacle devices may be installed as part of a convenience outlet installation
single outlet applications or in multiple feed through installations. (See E-188.8.131.52)
As has been mentioned, the EU has required whole vessel RCDs/RCBOs for several years. The US is simply catching up.