I don't know the ABYC code but a GFI, not just a simple breaker, has to be installed within a certain distance of the power inlet and preferably as close to it as possible.
hellosailor is on the right track but there are some details lacking. First of all, a GFI is not installed in the shore power circuit. The correct device is an equipment
interrupter (ELCI), also known as a residual current
device (RCD) and it has these trip thresholds: detected leakage of >30 mAAC with a trip time of <100 mS. A GFCI/GFI will trip when detected leakage >5 mAAC.
Here is the ABYC Standard:
"11.11.1 An Equipment
Leakage Circuit Interrupter (ELCI) or Type A Residual Current Device (RCD) 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-126.96.36.199.3 whichever is closer to the shore power connection."
As far as "compliance" with the ABYC Standards, these are voluntary standards, but boat builders who seek National Marine
Manufacturing Association (NMMA) certification
of their boats must comply with the large majority of the ABYC Standards.
There has been a struggle implementing ELCI installation
in the USA although RCDs have been required in the EU for years. The industry is now producing ELCIs and the latest guidance from ABYC as stated in the preamble to the latest ABYC E-11:
"NOTE: December 2011 Technical Amendment: Based on ABYC’s assessment of the existing technology regarding the Equipment Leakage Circuit Interrupter (ELCI), E-11.11.1 and its subparts carry a recommended compliance date of December 31, 2012."
So, to the OP question: yes, a double pole circuit breaker is required within 10', measured along the conductor, of the shore power inlet. Better yet, install an ELCI for safety's sake. If you operate in fresh water
, ABSOLUTELY install the ELCI.
> Blue Sea Systems p/n 3102100
> Blue Sea Systems p/n 3104