Your examiner asks you to describe the lights required for a power-driven vessel of 50 metres in length underway at night. Include arcs of visibility.

A. A power-driven vessel of 50m must show: a forward masthead light (225 degrees, white) at a height giving a visible horizon of at least 6nm; a second masthead light abaft and higher (225 degrees, white); sidelights — green (starboard, 112.5 degrees) and red (port, 112.5 degrees); and a sternlight (135 degrees, white). All visible at the minimum range required by Annex I. The two masthead lights are required for vessels of 50m and over.

B. A 50m vessel shows one masthead light, sidelights and sternlight. A second masthead light is only required for vessels over 150 metres.

C. A 50m vessel shows sidelights only at night. Masthead lights are shown only when at anchor or making way in a TSS.

D. A 50m vessel displays the same lights as a 20m vessel — there is no difference in light requirements between vessels of 12m and 150m.

A. The tidal height at the time of transit to confirm sufficient under-keel clearance

B. The yacht's fuel consumption for that leg

C. The colour of the seabed shown on the chart

D. Only the distance to the next waypoint

A. Switch the ECDIS to standby mode and navigate by GPS position alone

B. Ignore it — ECDIS alarms are frequently false and can be left running

C. Assess the situation against the planned route and charted depths, take action to maintain safe water, and inform the Master if there is any doubt

D. Acknowledge and silence the alarm immediately so it does not distract the helmsman