Crossing at Dusk in Broken Bay
It is 25 minutes after sunset on a clear evening in Broken Bay. You are alone in a 5.2 m open runabout, making about 12 knots on a steady course of due north, returning to a ramp at Palm Beach. Your navigation lights are working: a single all-round white light on a staff and red/green sidelights. Visibility is good but the light is fading. Off your starboard bow, roughly 30 degrees to your right, you see a single white light that appears to be moving slowly and is growing slowly brighter. There is no other traffic nearby and the water is calm. You are not in any marked channel or restricted area.
1. What does the single white light most likely tell you about the other vessel, and what is your obligation as the give-way or stand-on vessel?
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A single white light at night, with no red or green sidelights visible, is consistent with a vessel under 7 m at anchor or a small vessel showing only an all-round white light. Because you see only white and no sidelights, you cannot read its aspect, so you should treat it as a possible stationary or slow-moving hazard rather than assume it is crossing. Under the collision regulations, a vessel underway must keep out of the way of a vessel at anchor. Regardless of the technical stand-on/give-way label, the safest judgement is to treat it as a give-way situation: reduce speed, alter course to pass well clear, and keep watching until you are past. Do not assume the other vessel has seen you.
2. You decide to alter course to starboard and pass astern of the light. What checks should you make before and during the alteration?
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Before altering, look around the full horizon (not just ahead) for other traffic, including small unlit craft, and confirm no one is overtaking you. Check that the alteration is large enough to be obvious to the other vessel - a small nudge is ambiguous and can cause both vessels to turn into each other. Confirm your new course will keep a comfortable margin, and watch the bearing of the white light: if the bearing stays roughly constant while the range closes, you are on a collision course and must alter more. Maintain a safe speed for the conditions (dusk, fading light, single-handed) and keep a continuous lookout, since a small anchored boat may not be lit brightly.
3. As you approach the ramp you see a second vessel showing red and green sidelights and a white masthead light ahead and slightly to port, on a converging course. Who gives way, and why?
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Seeing both sidelights plus a masthead light means you are looking at the other vessel's bow - it is coming roughly head-on or nearly so. In a head-on situation both vessels are required to alter course to starboard and pass port-to-port. So you should turn to starboard; you do not have a stand-on option here. If instead the geometry were a true crossing (you see only a red or only a green sidelight), the vessel seeing the other's red light gives way. The key judgement is to identify the aspect from the lights rather than guess, then act early and obviously.