Avoiding a collision or a close quarter situation with other vessels or any other hazards to navigation is the most critical activity conducted at sea. Upon the watchkeeper's diligence rests the safety and security of the ship, the entire crew, the cargo, and the environment.
It is a demanding activity, requires support, encouragement, motivation, self-discipline and
a high standard of professionalism.
Collision might be defined when a ship strikes to or being struck by another ship, whether underway, anchored, or moored. To prevent disaster, watchkeeping officers must always comply with the International Regulations for Preventing Collisions at Sea. Compliance not only concerns the conduct of vessels in sight of one another but also under restricted visibility conditions. Under the steering and sailing rules, they must display the correct lights and shapes and make use of appropriate sound signals in poor visibility.
Furthermore, when a vessel becomes disabled, she must display correct lights and shapes to alert other traffic regarding her status of "Not Under Command." However, a vessel drifting close to a port with her engines deliberately slow down is not, for example, a
"vessel not under command" as defined by Rule 3(f) of the COLREGS.
Caution should always be observed when approaching other vessels. Vessels may not be
displaying their correct lights or shapes, or indeed their signals could be poorly positioned and
obscured by the ship's structure when approached from specific directions. In sea areas where
traffic flow is regulated, such as port approaches and traffic separation schemes, it may be
possible to anticipate movements from certain ship types. In these circumstances it is prudent
to allow extra sea room, as long as it is safe to do so.
In general, early and positive action should always be taken to avoid a close-quarters situation,
and once an action has been taken, the O.O.W. should always check to make sure that the action
taken is having the desired effect.
V.H.F. radio should not be used for collision avoidance purposes. Valuable time can be wasted
attempting to make contact, since identification may be difficult, and once a connection has
been made misunderstandings may arise.
In clear weather, the risk of collision can be detected early by taking frequent compass bearings
of an approaching vessel to ascertain whether the bearing is steady and the vessel is on
a collision course. However, care must be taken when approaching huge ships, ships
undertow, or ships at close range. An appreciable bearing change may be evident under these
circumstances, but in fact, a risk of collision may remain.
In restricted visibility, the conduct of vessels is specifically covered by the International Regulations
for Preventing Collisions at Sea. In these conditions, radar and, in particular, electronic radar
plotting can be effectively used for assessing the risk of collision. The O.O.W. should take the
opportunity to carry out radar plotting and observation practice in clear visibility whenever
possible.
The Master and all watchkeeping officers must be fully conversant with the latest edition and amendments of the International Regulations for Preventing Collisions at Sea.
The O.O.W. is to take frequent and accurate compass bearings of approaching ships to detect the risk of collision early. Such risk may sometimes exist when an appreciable bearing change is evident, particularly when approaching a large vessel or a tow or when approaching a ship at close range. He is to take early and positive action following the applicable Collision Regulations and confirm that such action has the desired effect.
Full use is to be made of radar and ARPA in assessing if the risk of collision exists. O.O.W. must not become complacent and rely solely on information from ARPAs. On ocean passages, there should be no need for vessels to pass at close quarters, and early and prompt action must always be taken.
For vessels using ECDIS, the O.O.W. must be aware that vessels not acquired and tracked by ARPA will not appear on the ARPA overlay on the ECDIS display. It is for this reason that ECDIS alone should not be used as a collision avoidance tool.
Maintaining a safe speed
Every vessel is required to proceed at a safe speed at all times in any condition of visibility so that she can take proper and effective action to avoid collision and be stopped within an appropriate distance. When determining a safe speed, rule 6 of the Collision Regulations must be referred.
Key factors to take into account are visibility, traffic density, and vessel maneuverability.
- The state of visibility: Despite operational radar, a visual lookout is always required by the Collision Regulations. If the visibility is significantly reduced, the ability of the lookout is hampered. While all ships carry radar, Rule 6 makes it clear that radar has many limitations and constraints. Accordingly, a great deal of reliance must therefore still be placed on the lookout.
- Traffic density: In coastal waters, it can be expected that the traffic density will increase, whether it be other commercial traffic, fishing boats, yachts, or other craft. The ability to maneuver and take proper and effective action can be restricted in such cases. If the vessel is going too fast, alteration, of course, to avoid one close quarter situation may result in another close quarter or even a collision. Therefore, masters and O.O.W.s are to pay attention to the actual density and anticipated density when taking into account a safe speed.
- Manoeuvrability: If stopping distances and turning circles are not taken into account, the vessel can easily find itself in a situation where a close quarter situation, a collision, or even a grounding is unavoidable. As a result, the vessel's maneuvering characteristics must be taken into account when determining a safe speed. The maneuverability varies a great deal between vessel types and drafts. A large, fully laden ship may have a stopping distance well above a mile with a huge radius turning circle, while a small vessel with twin screws can stop within a much shorter distance and turn almost within her length. Accordingly, a safe speed, taking only maneuverability into account, will differ greatly between vessel types.
- Other factors include the prevailing weather conditions, the proximity of navigational hazards, the effect of background lights, the draft in relation to the water and the various limitations and constraints of radar equipment.
Therefore, to determine a safe speed, all of the above factors must be taken into consideration. It is impossible to give figures here as every situation is different, and ship types vary in design and propulsion. However, the Master has to ensure that he and his deck officers are fully aware of the safe speed for his ship which will always be dependent on the prevailing circumstances and conditions.
Caution must be exercised when navigating in regions where high-speed craft (e.g., hydrofoils and hovercrafts) are operating. While these crafts can maneuver quickly, they are still required to comply with the Collision Regulations. Accordingly, the Master and O.O.W. on a conventional ship sighting a high-speed craft must never assume because of the additional maneuverability that these crafts will give way. Both the high-speed craft and conventional craft should act according to the Collision Regulations. Only by obeying the regulations will the risk of collision be removed.
Surveys and Gathering Information
At the earliest opportunity after a collision, the damaged vessels will be
surveyed. The surveyors appointed on behalf of each owner
will conduct joint surveys of both vessels on a without prejudice basis, usually
accompanied by the vessel's class surveyor.
Where there has been serious
damage, the hull and P&I insurers of each vessel will probably also arrange a
further survey to establish the speed of the ship and the angle of collision.
Lawyers may be sent to the vessels to interview crew and other witnesses and
to inspect logbooks, charts and other records.
Insurance claim
Almost any collision between two ships will involve insurers, given the near-certainty of some measure of damage requiring repair. There are two slightly
surprising aspects to conventional collision insurance; one is that under its running
down clause, a vessel's hull policy covers liability to third parties and the
other is that cover only extends to three-quarters of the liability, the other quarter
being borne by the vessel's P&I club.
Nowadays, the proportion of risk borne by the hull insurers can vary from all to nothing, with the balance usually being covered by the P&I club. The P&I club will typically also include other consequential
loss and damage resulting from a collision including personal injury, pollution,
wreck removal and damage to cargo on board the vessel entered with the club.
Because of the club's liabilities' potential scale, it will usually take the lead
role in dealing with a serious collision.
Further reading: Collision accident handling checklist
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