Right- and Left-hand Traffic - Vessels and Aircraft

Vessels and Aircraft

Generally, all water traffic keeps to the right, under the International Regulations for Preventing Collisions at Sea. This is historically because, before the use of a rudder, the boat was steered by a steering oar (or steer-board), which was located on the right-hand side, hence the starboard side of the boat. The helmsman used his right hand to operate the steer-board while standing in the middle of the boat and looking ahead. Traditionally, boats would also moor with the left hand side to the quay to prevent damage to the steering oar, and this was referred to as larboard (loading side), later replaced by port to prevent confusion from the similar sounding words. By keeping to the right, boats pass "port-to-port", protecting the steering oar. When modern style rudders fixed to the stern were developed, the helmsman was moved amidships (on the centreline), and when steering wheels replaced tillers this generally remained the same. Many motor yachts and other small craft are RHD, but some boats, typically smaller pleasure craft and wooden speedboats are built LHD, to give a better view of approaching and passing traffic.

However, there are exceptions to RHT when passing through bridges, normally indicated at each archway.

The rule of the road at sea is that powered vessels give way to sailing vessels; but as between two powered vessels, if they are crossing the rule is to give way to the starboard, while if they are head on each must navigate to starboard so as to pass port-to-port. q.v. The upshot is that the vessel attempting to pass on the wrong side must give way.

For aircraft and vessels, the US Federal Aviation Regulations provide for passing on the right, both in the air, and on water.

In aeroplanes with side-by-side seating, the pilot-in-command sits on the left, with the first officer, navigator or front seat passenger on the right. In most cases the controls are duplicated, Larger aircraft tend to have duplicate instruments on the right side as well, and in commercial airliners the first officer is just as likely to fly the aircraft from the right while the captain handles other tasks from the left. Helicopters generally place the pilot on the right, though examples exist with the pilot on the left.