Which category of able seaman is not authorized to be counted as an able seaman on a seagoing tug of over 100 gross tons?

Correct Answer: Option D — Special (OSV)

Under 46 CFR 12.401 and 46 USC 8702, an Able Seaman-Special (OSV) endorsement is restricted to service on offshore support vessels. Consequently, they cannot be counted toward the required percentage of Able Seamen on a seagoing tug.