46 CFR 184.404: Radars.

(a) A vessel must be fitted with a Federal Communications Commission (FCC) type accepted general marine radar system for surface navigation with a radar screen mounted at the primary operating station if:

(1) The vessel is self-propelled;

(2) The vessel has an oceans, coastwise, limited coastwise, or Great Lakes route; and

(3) The vessel carries more than 49 passengers.

(b) A ferry that carries more than 49 passengers on a rivers route not within one mile of land must be fitted with a FCC Type Accepted general marine radar system for surface navigation with a radar screen mounted at the primary operating station.

(c) The radar and its installation must be suitable for the intended speed and route of the vessel.

(d) A vessel operated on a short restricted route need not be fitted with a radar if the cognizant OCMI determines that a radar is not necessary due to the vessel's route and local weather conditions.