Navigation Safe Practices

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navigation safe practice

Collisions and groundings are a result of unsafe practices. Let look at the why collisions occur and how they can be prevented by implementing safe practices.

Collisions in Fog

The majority of collision claims seem to occur in fog or reduced visibility. Statistical analyses of these have shown that:

restricted visibility collision
  • The collision occurs during the watch of the second officer, (no explanation for this except perhaps fatigue?)
  • Both ships were proceeding at speeds that would not be considered safe
  • Neither ship was keeping a proper radar watch and
  • Collision often involved a misunderstanding as to what has been agreed during a VHF exchange between the two ships.

Many collisions worldwide occur this way. Difficult to understand is the fact that these causes have been highlighted continuously to no effect!

Rule 19 of the Collision Regulations governs the conduct of vessels in restricted visibility when vessels are not in sight of one another.

  • It states that every vessel should proceed at a safe speed with engines on standby.
  • It requires a vessel which detects another vessel by radar alone, to determine if a close quarters situation exists and to take avoiding action in ample time, particularly avoiding an alteration of course to port or an alteration which is directly towards another ship.
  • Rule 19 also states that on hearing a fog signal forward of the beam, or if close quarters cannot be avoided by an alteration of course alon then, if necessary, the ship should take off all her way.

In another case there was a head-on collision off the eastern coast of Honshu Island with both ships proceeding at full speed in fog. Ship A attempting to pass ship B starboard to starboard was under the control of a second officer; the master was below,

Use of VHF

The first collision occurred in the entrance to the River Plate. The entered ship was inward bound from Brazil and the other ship was outward bound from Montevideo for Brazil. The entered ship alleged that there had been exchanges on the VHF between the two ships well before the collision and that an agreement had been reached that, unusually, they would pass starboard to starboard but the other ship turned too late and the ships collided. The other ship denied that there was any special agreement and argued that therefore the ships should have passed port to port as usual.

The other ship alleged that just before the collision the ship ‘A’ strangely made a sudden turn to port, contrary to regulations, and the other ship tried to avoid her by turning to starboard in accordance with the regulations but the entered ship ploughed into the other ship’s port bow almost perpendicularly. Neither ship reduced speed. Neither master was on the bridge. An over reliance seems to have been placed on contact over the VHF radio and there may have been language difficulties. AVOID USE OF VHF unless both ships have clearly identified each other and unless there is a need for a discussion within pilotage waters.

The other collision occurred in the entrance to Felixstowe. The entered ferry was completing her regular service from Zeebrugge to Felixstowe and ran into an outward-bound Sip panish ship north and east of the Fort Buoy. Before the Spanish ship reached the Grisle Buoy her radar screen became distorted with interference and was there severe after useless. Her other radar was out of action. Instead of anchoring, the pilot and master decided to continue, effectively blind, in dense fog. The pilot had asked Harwich Port Control to tell him when he was passing the North Shelf Buoy.

At that time the entered ferry was in the vicinity of the North West Buoy and overheard the conversation. The master of the ferry assumed that the Spanish ship would be swinging to starboard rather wide and might get onto the Wrong side of the channel. He alleged that he kept as far over to the starboard side of the channel as he could, increasing speed to get out of the way of the Spanish ship, but the Spanish ship strayed too far over to the wrong side of the channel and the ferry struck the stem of the Spanish ship at an angle of about 12°, in the vicinity of the Fort Buoy.

The English Court held that the primary cause of the collision was the presence of the Spanish ship on the wrong side of the channel but the extent of the damage was caused by the ferry’s increase of speed and the court found that both ships were equally at fault. Subsequently, an amicable settlement was reached at two thirds/one third in favour of the ferry. Courts will normally penalise a ship, which increases speed in an emergency. The other ship should clearly have attempted to anchor when her radar failed rather than attempt to navigate blind in a difficult and narrow channel.

Collisions in Heavy Rain

A collision occurred in the Sunda Strait between Java and Sumatra when two vessels were navigating between reefs in dense rain and restricted visibility. The ship ‘A’ first observed the other ship on radar at about 4 miles to starboard. The master, concerned that he was passing too close to an island on the starboard side, assumed that the oncoming ship was on a near reciprocal course to his own and that he would help the other ship by altering course to port. Having altered 10° to port, he then called the other ship on VHF but without response. The target located on the ARPA radar was then lost in clutter. The master began sounding fog signals and made a further 20° alteration of course to port. The lookout spotted the other ship very shortly before the collision when the lights of the other ship appeared fine on the starboard bow, whereupon the master ordered hard to port. A collision could not be avoided and the ship ‘A’ struck the port side of the other ship.

This was yet another collision, which took place primarily because of neither ship properly, observing collision regulations, particularly with regard to manoeuvring in restricted visibility. Both ships were travelling at excessive speed and the ship ‘A’ made small alterations to port based on assumptions and thereafter took evasive action. This is in direct contravention to the Collision Regulations (Regulations 18 and 19). The entered ship should have reduced her speed drastically in the conditions prevailing and should have maintained her course until the course and speed of the other ship had been ascertained, or until she had been sighted visually. A reduction in speed can often be more useful in preventing collision than a change of course.

Collisions – Keep to starboard and misuse of VHF

Rule 9 of the Collision Regulations, which deals with navigation in narrow channels, reads in part:

A vessel proceeding along the course of a narrow channel or fairway shall keep as near to the outer limit of the channel or fairway, which lies on her starboard side as, is safe and practicable.

However, collisions commonly occur in narrow channels when one or both ships are found on the wrong side of the channel. This is surprising as narrow channels are often areas of compulsory pilotage.

Recently a collision occurred in the River Parana off San Nicolas. The ship ‘A’ was proceeding up river at a speed of ten knots, keeping to the starboard side of the channel. The other ship had just left San Nicolas to proceed to sea. (San Nicolas is positioned on the starboard side of the channel for ships travelling down river.) On board the other ship were a harbour pilot and river pilot and once clear of the port, it was necessary to drop the harbour pilot. Engines were stopped and the ship positioned so that the pilot ladder was in the lee of the wind. A turn to port was necessary, but the ship drifted on to the wrong side of the channel.

There was clear visibility and the master and pilot on ship ‘A’ could see the danger ahead. However, instead of reducing speed or even stopping, he altered course to port to pass the other ship on her starboard side. This decision was allegedly communicated to the other ship on VHF. What was actually agreed between the two pilots remains in dispute, but as soon as the harbour pilot was away, the engines on the other ship were put ahead and the helm to starboard. The collision was inevitable.

This type of incident is common. The use of VHF to agree the manner of passing, particularly an alteration of course to port in order to pass starboard to starboard is dangerous. Warnings have been issued about the use of VHF to agree a manoeuvre., which is contrary to the Collision Regulations. it is stressed again that it is much safer to reduce speed or even stop to let the other ship ‘get out of the way’, than to alter course to port.

If the Collision Regulations had been followed, this is another collision, which would have been avoided.

Collisions — timely actions

The deplorable fact is that the Collision Regulations are disregarded all too frequently. The structure of the Collision Regulations is designed to ensure that, whenever possible, ships will not reach a close-quarters situation in which there is risk of collision and in which decisions have to be taken without time for proper thought.” So said the leading English admiralty judge, in collision case last year. He went on to say:

“Manoeuvres taken to avoid a close-quarters situation should be taken at a time when the responsible officer does not have to make a quick decision or a decision based on inadequate information. Those manoeuvres should be such as to be readily apparent to the other ship. The errors of navigation, which I regard as the most serious, are those errors, which are made by an officer who has time to think. At such a time there is no excuse for failure to comply with the Collision Regulations.

Likewise there is no excuse for a master who accepts low standards and bad practices in his ship, particularly on the bridge or in the engine room. When a ship is being navigated in reduced visibility, the master should ensure that he is alerted in good time if other ships are known to be in the vicinity and a close-quarters situation may develop. The master must also ensure that the officer on watch is keeping an efficient radar watch by observation and plotting of contacts. He should positively discourage distractions such as R/T conversations and any reluctance to reduce speed or, if necessary, to stop the ship. It is very probable that the use of VHF radio for conversation between these ships was a contributory cause of this collision, if only because it distracted the officers on watch from paying careful attention to their radar. I must repeat, in the hope that it will achieve some publicity, what I have said on previous occasions, that any attempt to use VHF to agree the manner of passing is fraught with the danger of misunderstanding. Marine superintendents would be well advised to prohibit such use of VHF radio and to instruct their officers to comply with the Collision Regulations.”

Collisions – Low standard of Watchkeeping

In one case, a ship ‘A’ collided with a tug and barge at night in good visibility, off Houston, Texas. The tug and barge were showing proper lights for ships restricted in their ability to manoeuvre. Therefore, the ship ‘A’ was the give-way ship. The ship was under the control of the second officer who had only just joined the ship and was standing his first navigational watch when the ship was leaving Houston. Traffic in these waters is dense and there are many oil plaforms. He mistook the tug and barge for a platform, with the tug standing by.

The second officer should have been able to distinguish easily between a tug towing and a supply-boat standing by. He did not plot the tug and barge, neither on the radar nor by taking visual bearings. if he had done so, he would have noticed that the bearing of the other vessel was not changing. Since he was navigating in a buoyed channel, this would have alerted him to the fact that he was approaching another vessel underway, rather than passing a platform. The master should have stayed on the bridge to evaluate the second officer’s watchkeeping ability before allowing him to take control in such a difficult area. If the master was too tired to do so, one must question whether the ship was properly manned.

In another case, a container ship, on passage from Busan to Kobe, collided with a Japanese fishing boat. The visibility was four miles and the container ship was the give-way vessel because the fishing boat was on her starboard bow and was displaying the proper day shapes for a fishing boat. The second officer, who was on watch. perhaps noticed the fishing boat too late and failed to alter course or to reduce speed.

In all the cases reported the officer who was on watch in each case, failed to apply the Collision Regulations or, indeed the principles of good seamanship.

Grounding: Act – Don’t “wait and see”

The dangers of a “wait and see” policy when at anchor in impending heavy weather often cause major stranding and occasionally, total loss. The potentially disastrous consequences of following such a policy are graphically illustrated by another incident recorded recently.

In this incident, a ro-ro cargo ship had anchored in Cadiz Bay prior to bunkering at the Rota naval base. The designated anchorage for Rota is very exposed, there being no shelter from the southern semicircle and the manoeuvring room is limited. A weather forecast indicated that southwesterly winds of 35-40 knots, gusting to 60 knots in thunderstorms, were expected. in accordance with the owner’s standing orders, the main engines were brought to immediate notice. Subsequently, with gusts of 70 knots being experienced, the watch officer determined that the ship was dragging and attempts were made to weigh the anchor. The ship was yawing badly and main engines were used as required to relieve the weight on the cable. With the cable shortened to two shackles, the ship swung beam on to the wind as the stern grounded.

With the anchor finally aweigh, attempts were made to manoeuvre clear and depart the anchorage, these being complicated by the presence, in close proximity, of another ship, which was also dragging her anchor. These attempts proved unsuccessful and it was subsequently ascertained that the ship had grounded over almost her full length on a rocky shoal, half a mile from the beach.

This incident was solely attributable to the master’s failure to take early and appropriate precautions for the safety of his ship following a severe weather forecast when at anchor. In addition to bringing the main engines to immediate notice, he should have taken into account the exposed nature of the anchorage and the restricted manoeuvring room. Additionally, the ship was known to yaw badly when at anchor in heavy weather, which may significantly have diminished the anchor’s holding power.

Had the master considered these factors, this incident may have been avoided. The prudent course of action would have been to weigh anchor and proceed to sea before the weather deteriorated significantly. In the event, when the ship started to drag her anchor, the difficulties in weighing anchor in the prevailing conditions, exacerbated by the heavy yawing and the close proximity to shoal water, resulted in her grounding aft before the situation could be retrieved, despite the immediate availability of main engines.

It is recommended that their bridge procedures require the masters to take early and positive action under such circumstances and never to adopt a ‘wait and see” approach.

Radar Watchkeeping

When a collision occurs in fog, heavy rain or reduced visibility, a major contributing factor is failure of one or both ships’ navigators to use their radar properly. Some navigators fail to plot an approaching ship, some fail to look at the radar at all, and others do not understand the use of the clutter control.

Two collision claims and one case involving a ship striking a buoy cost the Club $3.4 million. Although, if the navigators had used their radars properly, these claims would have been avoided.

In the first incident, two tankers were navigating on reciprocal courses, in visibility, which was reduced by wind blown sand. Each ship detected the of by radar at twelve miles. Neither navigator plotted the other ship’s approach, but assumed that they were approaching each other end on. With the aim of avoiding a close quarter situation; each navigator made a course alteration, one, 5° to starboard, the other, 5° to port. Sometime later, each navigator became aware that the approaching ship was still ‘end on’ so each navigator again made the same course alteration (5° to starboard and 5° to port). This happened a third time, and even then, neither navigator plotted the approaching ship on his radar. Inevitably, the two ships
collided in what was a classic radar assisted collision.

The Collision Regulations are clear in their instructions; Rule 19 (vessels not in sight of one another) states that an alteration to port should be avoided, while Rule 14 (vessels in sight of one another) instructs vessels, which are end on, or nearly end on, to alter course to starboard Had both navigators complied with the Regulations and made a bold alteration of course to starboard, there would not have been a collision.

The second incident involved a reefer ship and a VLCC navigating in a heavy rain squall. The reefer was the give way ship, having the other ship approaching on her starboard bow However, the ships were not in sight of one another. Both ships were travelling at their full sea speed, on automatic pilot. The navigator on the reefer was busy in the chart room and had posted a lookout (there being no radar in the chart room). To assist the lookout, he put the radar onto long range and set the clutter control to the 75% setting. Periodically, he left the chart room to look at the radar. On the VLCC, the navigator was alone on the bridge. The collision occurred when both ships suddenly appeared out of the rain and ran into each other. Neither navigator had detected the other approaching ship.

This incident clearly demonstrates the importance of keeping a radar watch when visibility is reduced by rain and not just when navigating in fog. Indeed, the two ships were far from land, neither expected to meet crossing traffic, and apart from the heavy rainsquall, visibility was excellent. One of the factors in this and the next incident was failure in the correct use of the clutter control.

In the final incident, a supply vessel was standing off a rig in rough seas. As is the practice, the navigator was keeping station with reference to visual points and was not plotting the ship’s position on a chart, when suddenly the ship collided with an unlit but charted buoy. The echo from the buoy had been lost in interference from sea waves (sea clutter).

There are clear lessons to be learnt from all these incidents with failure to plot the approach of another ship being the most important. The first incident demonstrates the danger of navigating in wind blown sand, when visibility may appear to be better than it really is. It highlights the folly of attempting to put a ship, which is fine on the starboard bow further to starboard by altering course to port, while in the second and third incidents the clutter control was the primary cause.

OOW are reminded that the purpose of clutter suppression is to eliminate echo returns from sea waves (which are greatest near the ship) but the clutter control suppresses rain. When the clutter control is applied, the ‘tail’ of an echo is cut off so that only the leading edge is displayed. Echoes from ships and buoys are much stronger than echoes from waves and, even though the strength of these echoes will be reduced, they will still be displayed, even though echoes from waves, and to an extent rain, will not. However, if clutter suppression is set to maximum, then even echoes from large ships may be lost. While if clutter suppression Is set too low, echoes from small buoys can be drowned by echoes from waves or ram. For this reason, it is necessary to vary the setting of the clutter control.

Navigators are reminded of the importance of using the radar in a searching manner that is, changing ranges and adjusting the clutter suppression. The clutter suppression should never be set and then left on one setting.

Navigators are also reminded that whenever visibility is reduced, a radar watch should be maintained, the ship put on to manual steering, and a lookout posted until visibility improves. Approaching targets should be plotted and their true course, speed and ‘closest position of approach’ (CPA) calculated. Masters are strongly recommended to encourage their officers to practise radar plotting during periods of good visibility as this builds user confidence in the equipment.

Transverse thrust

The operation of a propeller is a complex interaction between fluid flow, after-end design and propeller design. The main element of a propeller’s thrust is forwards or backwards. However, every ship’s master knows that a single screw ship fitted with a right-hand turning propeller will have a tendency to turn more readily to port than to starboard when going ahead and will do the opposite when going astern. This effect is referred to as ‘transverse thrust and is thought to originate from fluid passing through the propeller in close proximity to the ship’s hull.

Ship masters do not need to understand the complex hydrodynamics which cause this force, but they do need to understand how the force affects their ship for different conditions of loading and when operating in an open or restricted seaway.

A recent dock damage claim which occurred when an LPG carrier struck and demolished a mooring dolphin would have been avoided if the master had realised that the full astern manoeuvre would cause the stern to swing to port and consequently the bow to starboard.

The ship was manoeuvring to berth with her starboard side alongside. A tug was attached forward and aft and a pilot was on board. The wind was light and variable and a current was running from ahead at about 0.5 knots.

The approach was made at a relatively high speed, parallel and close to the jetty face. As the bow came level with the mid-point of the jetty, engines were put to full astern to reduce the headway and to stop the ship from overshooting. The bow swung immediately to starboard. Transverse thrust, exacerbated by the current, was the cause. Even though the forward tug tried to stop the swing, the ship’s bow struck the mooring dolphin, which was, sited 17.5 metres inshore from the quay edge and therefore protected from contact damage during normal berthing port quarter with a
manoeuvres. Furthermore, the after tug was attached on the port quarter with a very short lead and could do nothing to stop the swing . Had the master realised this would happen, he would have allowed the ship safely to overshoot the berth.

The effect of transverse thrust in a single screw ship should never be underestimated, particularly when manoeuvring in close proximity to structures and when moving astern. Masters should also bear in mind that manoeuvring in shallow water or close to canal or river banks may significantly alter the effect of transverse thrust, either increasing its strength or, in some instances, reversing the anticipated direction. For this reason it is essential to have tugs properly deployed.

There are few opportunities for a master to assess the effects of transverse thrust on his ship, in practice, but occasions may arise when this can be accomplished safety when anchoring or embarking a pilot. Masters should use every opportunity to assess this effect, particularly if they are unfamiliar with the handling characteristics of their ship.


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