Look-out.
Every vessel shall at all times maintain a proper look-out by sight and hearing, as well as by all available means appropriate in the prevailing circumstances and conditions so as to make a full appraisal of the situation and of the risk of collision.
This rule looks straightforward enough, but there are several aspects to it.
A typical modern ship with speed of 20Kts covers approximately 620 m per minute, When visibility is about 6 NM and object is large, she sees only 18 minutes of time.
This means lookout quality has to be high and always alert
Good watchkeeping is an art, which needs practice. Judging distance-off and accurately assessing the size and relative courses of other vessels is something, which no amount of instruction or studying of texts can ever teach. It can only be gained from experience.
An autopilot can be a menace or a real help, depending on how it is used.
But when used simply to keep a steady course, additional set of eyes are available for lookout. Person steering the vessel (Helmsman) is not considered as a lookout man. He cannot be both a helmsman and a lookout man.
Most importantly, a ‘proper look-out’ means one, which takes in the whole 360-degree panorama. Crew assisting the OOW must report what they observe or hear.
Not all Bridges allow unrestricted visibility. Many are obscured to the rear and have significant blind spots. These blind spots also apply to Radar detection. If Rule 5 were to be obeyed, it would be prudent to have one person on lookout duty on the bridge wing, to assist the OOW whose view is inhibited by the superstructure. When navigating at night, it is vital to preserve night vision and not be dazzled by your own ship’s instrument or navigation lights. Any prescription spectacles should be worn and kept clean. Sunglasses and/or a peaked cap may cut down glare, especially when looking towards the sun.
“All available means” also include such things as radar and VHF radio, in order that warnings from other vessels and the Coastguard may be received and heeded. Keeping a lookout “by all available means” could also be interpreted as having and using, a decent pair of binoculars and night scopes. However it should be noted that carrying a pair of binoculars on board, is not a requirement under any existing IMO legislation.
Also note that Rule 5 says a lookout should be kept by hearing. It is therefore prudent to try and keep one of the bridge wing doors open (the leeward one is a good bet) if at all possible.
Remember that the intensity and direction of sound is particularly difficult to judge.