94038 Mis-use of Deep draught Signal

Mis-Use of Deep draught Signal
Report No. 94038

 

At approximately 0500 on a bright summer morning, three vessels were crossing, or about to cross the NE lane of the Traffic Separation Scheme in the vicinity of the F3 buoy. Own vessel was in the lead, heading 2850 speed 19 knots, followed by a a container vessel of about 30,000 tonnes on a course of 2900 and doing 18 knots and a freight ferry en route from Zeebrugge to the Thames on a course of 2950 and speed of 16 knots. In the NE lane, approaching the F3 buoy from the Deep Draught route, was a VLCC on a course of 0550 and with a speed of 15 knots.
Own vessel passed ahead of the tanker at a range of 1 to 1_ miles, the container vessel was about 1_ miles astern of me and the freight ferry 4 miles astern. Watching my ARPA, I noted that the CPA of the tanker and the container vessel was almost nil. I heard the tanker calling the container vessel on channel 16 at a range of 2 miles, there was no reply. The tanker repeated the call at 1.5 miles range, again there was no reply. I was not visually observing the situation astern of me as I was concentrating on the traffic in the SW lane.

On hearing the second message, I looked to see what was happening. The container vessel was altering course to port and by the amount it heeled over it appeared to be a full rudder turn. At the same time the tanker also altered, apparently under full rudder, to starboard. At this stage the VHF burst into life with confused messages about what each vessel should do. The container vessel completed a full round turn to port eventually, it's speed falling to about 4 knots when it had completed 1800 turn (engine stopped as well as use of rudder?) The tanker altered to a course of about 1000 and then altered to port around the almost stopped container vessel to resume it's passage.

There are two disturbing factors about this incident:

1. The container vessel altered to port at close range and the eventual CPA was well under half a mile.

2. An even more disturbing feature was one particular message from the flag of convenience (Marshall Islands Register) tanker. This message was to the effect that "I had three red lights up with a draught of 20 metres – you should have kept clear of me". In this area there is no patch of less than 30 metres of water – the tanker used three red lights as an excuse to ignore the Collision Regulations – a not unusual happening in the area.
The following is a reply to the criticisms of MARS 94038 in the Letters column of SEAWAYS JUNE 1995. This has been sent to me by the originator of the report.

The incident was witnessed at close quarters - at no time was I more than five miles away, initially I passed about two miles away from the tanker involved.
The chart used was Admiralty Chart 323, a copy of the relevant area being enclosed.
The original track of the tanker was along the NW edge of the route as shown. The track of the container vessel was close to the course line shown.
The point at which these tracks crossed was about the 35m sounding shown, outside the designated area of the Deep Water Route.
At this point the nearest shallow water is a 26m patch some mile and a half to the ESE.
From a point about two miles before the intersection of the tracks there is no other shallower water than 30m within a mile of the tanker's track. At a range of two miles the tanker would have been able to alter 300 without coming within a mile of the 26m patch, possibly even more.
I enclose a copy of section 4 of chart 5500. I would continue the quote of Captain Brady to a couple of lines further down the page < Vessels "constrained by their draught" should show the appropriate lights and shapes only when actually so constrained......A vessel navigating with a small underkeel clearance but with adequate space to take avoiding action should not be regarded as being constrained by her draught.> (report author's italics)
It is obvious that my view of the relevance of the "deep draught" signal differs from Captain Brady, I stand by my view that it was being incorrectly displayed.
Notwithstanding that opinion, even if the navigator of the tanker did hold the same view as Captain Brady, the tanker still had the option of slowing down – the close quarters situation would have been apparent for several miles.
All the above takes no account of the additional water due to tide but is looked at using chart datum. This long after the event I regret that I cannot calculate the tides as my memory of times would be insufficiently accurate. However, any tidal height would strengthen my case.
I appreciate the comments by Captain Brady regarding any swell effects – the MARS report did state a "bright summer morning" – I can confirm now that the sea did resemble a mill-pond with no discernible swell - an omission in the original report.
One comment is refuted totally "....but does seem to know that the container vessel had stopped engines". The MARS report is quite clear "...(engine stopped as well as use of rudder?)" – the question mark indicated that this was a surmise and not a fact.
Nothing in this answer does anything to excuse the altering to port of the container vessel when in a close quarters situation.
Overall I still believe the fault was split, the situation could have been eased by the tanker taking action, either alteration of course or speed, that he did not was indicative that he relied on the deep draught lights which were incorrectly displayed. The container vessel was not at fault in maintaining his course and speed but only faulty by his action when it became obvious to him that the tanker was not going to comply with the rules.