Here's what I found on the Coast Guard site:::
Sea Service Requirements
Reference:
46 CFR
# of Days
Eval INT
Recency – 90 days in the past 3 years on vessels
11.201
OUPV
46 CFR
Near Coastal – 360 days of service, OF WHICH
90 days of service on Ocean or Near Coastal waters.
11.467
Great Lakes - 360 days of service, OF WHICH:
90 days of service on Great Lakes.
11.467
Inland – 360 days of service.
11.467