Running down or 3/4ths collision liability clause (RDC). Under the Institute Time Clauses (Hulls) 1983 it is agreed that if the insured vessel is to blame for a collision with another vessel, underwriters undertake to pay three-fourths of the damage sustained by the other vessel up to a maximum of three fourths of the value of the insured vessel mentioned in the policy.
Reversible laytime. "Reversible" means an option given to the charterer to add together the time allowed for loading and discharging. Until this total time expires, no demurrage becomes payable. When the option is exercised the effect is the same as if a total time was specified to cover both operations.
Reachable on arrival. (See also Always accessible.) In the Charterparty Laytime Definitions 1980, this expression is defined as meaning that "... the Charterer undertakes that when the ship arrives at the port there will be a loading) discharging berth for her to which she can proceed without delay".
Rotation number. This is given to a ship by port authorities, especially by Customs authorities, to indicate the ship's turn to berth for loading and/or discharging. It is based on the ship's arrival and reporting by the master or agent to the port authorities. In chartering, the term would then be related to the clearance of the ship and whether the ship can give a Notice of Readiness.