An encounter between a yacht and a large passenger vessel, where navigation lights were difficult to distinguish amongst other deck lights.
What the Reporter told us:
My yacht was under sail progressing in a southerly direction. I saw the lights of another vessel off my starboard bow. At some distance, I made out what I thought was a green light and believed that the other vessel was a cross channel ferry heading north, well clear of my vessel. As we closed, it became clear that what I had thought was a green light was in fact blue, but another green light became visible, so I continued to believe this was a ferry heading north and clear of my vessel. However, the relative tracks didn’t seem to make sense if I was seeing a starboard navigation light. Eventually, the vessel crossed my track about a mile ahead – it was a cruise liner going from west to east. I should, therefore, have been able to see the port navigation light but, even with hindsight, I could not convince myself there was a red light in amongst the multitude of other lights visible on the cruise liner. This is a common issue with cruise liners – and this one is no worse than some others.
On this occasion, there was no harm as the other vessel was a safe distance ahead and we were the stand-on vessel. However, because we only saw what seemed to be a green navigation light and, therefore, misinterpreted the situation, had my vessel been under power, we would not have known that we were the give way vessel until very much closer, and then only because the track wasn’t making sense, not because we identified the red port navigation light.
The Collision Regulations specify the minimum visibility of navigation lights. However, the impact of other bright lights simply obscuring the navigation lights, (as was the case when the vessel was 1 mile ahead), or being positively misleading (as was the case initially when the only coloured lights I could see were green), is not appreciated. Vessels should ensure that their navigation lights are bright enough to be seen against the background of all their other lights, and avoid using coloured deck lights where this can cause confusion.
Very bright deck working lights obscuring navigation lights are often an issue on fishing boats as well.
The Maritime Advisory Board highlighted the importance of taking a series of compass bearings in order to determine whether a risk of collision exists. Navigation light visibility – irrespective of other lighting – must comply with COLREGS Annex 1.
In addition, they queried why classification societies permit these designs where visibility is obscured. Technology exists whereby deck lighting may be adequately shaded – permitting safe movement on board yet not obscuring regulatory lights.
The quality of light bulbs used is another possible consideration. Take LED for example – are approved suppliers holding the introduction of these back due to a lack of any requirement in COLREGS?