200746 Near misses on deep water route

	MARS Report 200746

It is regularly observed by our shore radar that small and medium sized vessels with drafts of less than seven metres continue, wrongly, to use the deep-water (DW) route that is established along the outer sea approaches to the port. This route is exclusively meant for very large vessels drawing up to 17.8 metres and is clearly marked on all relevant large-scale navigational charts. Further, we recently observed a near collision on our radar due to failure to observe Colregs on the part of a small vessel 'A' (blue below) that was navigating on an easterly heading in the DW route. Vessel 'B' (brown) was on her starboard side, steering a northerly course and there was risk of collision with 'A'. However, 'A' did not take any action despite clearly being the give-way vessel, perhaps due to the mistaken notion that as she was following a DW route, she had right of way. When 'B' took unilateral evasive action by going full round to starboard, we measured a CPA of 0.2 nm, which could have been less due to radar limitations and the long range.
We also see with alarming regularity, that northbound coastal vessels (yellow) crossing the DW route take no action to avoid impeding deep-draft vessels (red) that can navigate only within the DW channel. These cannot reduce their speed below a certain minimum when inbound due to tight limits of their tidal window.

Editor's note

A survey published by The Nautical Institute in July 2003 revealed an alarming tendency among ships' officers to believe, mistakenly, that when following a traffic lane or even a deep water route, they would expect a crossing vessel on their starboard side to give way. Masters and trainers have to ensure this misunderstanding is eliminated.

Colregs Rule 18 (d) (i) states: 'Any vessel other than a vessel not under command or a vessel restricted in her ability to manoeuvre shall, if the circumstances of the case admit, avoid impeding the safe passage of a vessel constrained by her draft, exhibiting the signals in Rule 28.'

In MARS 200732, a vessel was reportedly fined by the coastguard for exceeding the size limit for the use of an inshore traffic lane in the North Sea. It can be expected that ships violating DW routes may also be similarly penalised, and the navigating officer may face further interrogation by the PSC, the flag state authorities and the government that issued his or her certificate of competency/licence.