SHIP DIRFTING OFFSHORE BEST PRACTICE. LOCATION, TRAFFIC, WEATHER AND MORE

Published: 21 February 2023

When ports are congested and there is no suitable anchorage available, ships may need to drift offshore while waiting for a berth.  In recent years it seems that ports have become more congested and so there has been an increased number of ships drifting offshore.  This drifting, which may seem straightforward, can involve risks.

In this article the loss prevention team set out the best practice guidelines for ships when they need to drift offshore.

LOCATION

When selecting a location to drift, these areas should be avoided:

• Traditional traffic routes
• Harbour limits
• Areas where restrictions may apply e.g. particularly sensitive sea areas or fish farms
• Offshore oil and gas fields
• Fishing grounds
• Traffic Separation Schemes and inshore traffic zones
• Any other areas with navigational warnings e.g. naval gunnery exercise areas or areas where there are pipelaying activities

Passage plans set out the proposed route from berth to berth but they should also set out defined areas where drifting can be safely undertaken, bearing in mind the areas to avoid as set out above. These safe drifting areas should be set out in the passage plan and clearly marked on the chart.

If the ship is drifting within a state’s territorial waters then the ship may also need to alert the local authorities of their position.  There may also be other declaration formalities when a ship is within territorial waters, such as the need to seal off the bonded stores to avoid custom fines.  The ship’s local agents should be consulted to advise if any such requirements exist.

NAVIGATION

When a vessel is drifting, the master may consider that the vessel is ‘Not Under Command’, in accordance with the description contained in COLREGs Rule 3 “General Definitions” and display two all-round red lights or two balls or similar shapes in a vertical line in accordance with Rule 27 “Vessels Not Under Command or Restricted in Their Ability to Manoeuvre”.

Rule 3 states:

“The term “vessel not under command” means a vessel which through some exceptional circumstance is unable to manoeuvre as required by these Rules and is therefore unable to keep out of the way of another vessel”.

if a vessel has shut down the main engine(s), this would not ordinarily be an “exceptional circumstance”, rather, the vessel for the purposes of COLREGs compliance, remains a power driven vessel that is underway, just not making way, and is obliged to show the lights required by Rule 23 – “Power-Driven Vessels Underway”, i.e. the usual navigational lights; masthead, side and stern lights.

Passage planning should address drifting, considering the guidance in this article, and Britannia’s Loss Prevention Insight: “Safe Passage Planning – An Overview for the Maritime Sector”.

TRAFFIC

When drifting, as the vessel is underway, just not making way, a full navigational watch on the bridge should be kept at all times.  This will include maintaining a careful lookout by visual and all available other means, along with assessing the risk of collision, and taking action to avoid collision when necessary.

Although  not specifically addressed in the COLREGs, good seamanship would dictate that a vessel underway and making way should pass around a vessel that is obviously stopped and not making way. However, the vessel that is drifting should be mindful of the requirement to start their engine if necessary so as to manoeuvre the vessel clear in the event of a potential collision or close quarters situation developing.

MACHINERY

It may be necessary for a drifting vessel to move promptly due to increased rate of drift or proximity to land or in order to take action to avoid a collision or risk of collision.  Therefore, propelling machinery and steering gear should be maintained at a suitable state of readiness at all times. It is recommended that any maintenance that would make the main engine and/or the steering gear unavailable is not undertaken when drifting. Whether the engine room can be left unmanned while drifting should be decided by the chief engineer in close consultation with the master taking into account, as minimum, the influential conditions highlighted in this guidance. If unmanned, a minimum notice period for the duty engineer should be agreed.

WEATHER AND ENVIRONMENT

A close watch should be kept on the weather, monitoring the weather forecasts and also the effects of tide and currents on the movement of the vessel. The drifting position should consider these so that the vessel has adequate sea room and will not close on the shore or other danger. Usually the vessel will periodically need to reposition after a period of drifting to maintain an adequate margin of safety away from the shore or other potential navigational hazards. In the offshore industry, where vessels often drift in the vicinity of offshore installations, the action of drifting and then slowly steaming and repositioning is known as “laying and dodging”, or simply “dodging”.

In the event that weather conditions are forecast to deteriorate, the drifting location should be evaluated and it may be necessary to move further away from the coast and any navigational hazards, to provide a greater margin of safety.

Depending on the vessel’s stability condition, the weather conditions and in particular the height of and period of encounter with the swell may mean the vessel will roll heavily when drifting and lying with the swell on the beam. Such a situation may be uncomfortable for the crew, detrimental to the cargo stow and its securings, and may even cause fuel to spill via vents from almost full fuel tanks. Therefore the circumstances when drifting should be continually monitored, and there may be situations where drifting is not suitable, and rather the vessel should slow steam to minimise vessel movements.

If a vessel finds itself in difficulty, due to, for example, machinery failure, procedures as per the emergency guidance manual should be carefully followed, however, any assistance required from third parties, such as tugs, should be promptly summoned, as far too many vessels have grounded due to delays in calling for assistance.

PIRACY AND ARMED ROBBERY

The risk of piracy and robbery whilst on the high seas is very real in many areas and so when evaluating the risks associated with a particular location selected to drift, it is worthwhile consulting the ICC / IMB Piracy and Armed Robbery Maps, for number, nature and location of attacks. While many such incidents occur close to shore, there have been pirate boardings several hundred nautical miles from the coast.

Where a risk of piracy and/or armed robbery exists, compliance with, so far as is practicable, the provisions recommend in the latest editions of Best Management Practices and Best Management Practices – West Africa, and Global Counter Piracy Guidance for Companies, Masters and Seafarers, as well as on the Maritime Security Charts published by the United Kingdom Hydrographic Office is recommended. Careful consideration should be given, however, to ensure that when illuminating decks and over the side, that navigation lights remain clearly visible.

Where voluntary anti-piracy reporting arrangements are in place, vessels are recommended to participate and report accordingly, further guidance can be found here.

Members requiring any further assistance with this topic can contact the Loss Prevention department at lossprevention@tindallriley.com

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