Question 1

A vessel is engaged in underwater operations (e.g. survey or salvage diving) and displays the shapes for "restricted in ability to manoeuvre," with an additional shape indicating which side an obstruction lies. What additional shape might be shown, and what does it mean?

Accepted Answer

Two black balls or two diamonds in a vertical line, displayed on the side on which another vessel may pass — indicating an obstruction exists on the opposite side, so vessels should pass on the side where the balls/diamonds are NOT displayed only after assessing the safe side as indicated Rule 27(d) allows a vessel restricted in her ability to manoeuvre while engaged in operations creating an obstruction to show additional shapes (two balls or two diamonds) indicating the side on which the obstruction lies and/or the safe passing side — important information for vessels navigating close by.

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.