Question 1

A vessel restricted in her ability to manoeuvre (e.g. engaged in dredging or underwater operations) displays a ball, diamond, ball in a vertical line by day. What does this combination represent, and why does it matter to nearby traffic?

Accepted Answer

It is the day shape prescribed by Rule 27 for a vessel restricted in her ability to manoeuvre — such a vessel, due to the nature of her work, has limited ability to deviate from her course, so other vessels should keep clear and avoid impeding her, with extra care if the vessel also shows additional shapes indicating an obstructed side Rule 27 prescribes the ball-diamond-ball combination for vessels restricted in their ability to manoeuvre — recognising this shape helps other vessels understand that this vessel cannot readily get out of the way and should generally be given priority/sea room.

Question 2

Rule 5 (Look-out) requires every vessel at all times to maintain a proper look-out by sight and hearing, as well as by all available means appropriate in the prevailing circumstances and conditions — and this duty applies even when the vessel is at anchor in a busy anchorage.

Accepted Answer

True True. Rule 5 applies 'at all times' and to 'every vessel'. A vessel at anchor in a busy anchorage still needs an effective look-out to detect drifting vessels, dragging anchors, or approaching traffic that may pose a risk of collision or contact.

Question 3

Under Rule 6 (Safe Speed), a vessel fitted with a fully operational radar and ARPA never needs to reduce speed in restricted visibility, because the equipment guarantees early detection of other vessels.

Accepted Answer

False False. Rule 6 explicitly lists radar capability as one factor to consider, but also requires accounting for the state of visibility, traffic density, manoeuvrability, and the limitations of radar (range scale, sea/rain clutter, blind sectors). Even a vessel with excellent radar must proceed at a speed that allows proper and effective action to avoid collision and to be stopped within a distance appropriate to the prevailing circumstances.