Not all AB endorsements have requirements on the size or route of the vessels the service is from. The requirements are as follows:
AB-Unlimited: 3 years on Great Lakes or “at sea” (near coastal/oceans) 46 USC 7307
AB-Limited: 18 months on vessels at least 100 GRT 46 USC 7308
AB-Special: 12 months 46 USC 7309
AB-OSV: 6 months 46 USC 7310
The 65’ requirement was for AB-MODU, and since AB-MODU is not authorized in the CFR or US Code, we are no longer issuing them.
STCW RFPNW has some requirements that may effect your ability to get an STCW certification, and thus ability to work as AB: at least 50% of the 6 months for RFPNW have to be on vessels at least 200 GRT, and all assessments have to be done on vessels over 100 GRT.
The AB course at Young Memorial takes the place of the Coast Guard exam at the REC. You still have to meet the sea time above, but you won’t take an exam from the Coast Guard. Make sure your time is good before you take the course, it’s only good for one year.