Increased Risk of Collision Off Singapore -Passage planning in confined waters
Confined waters mean an area of the sea where the width of the safely navigable waterway is not more than about 2 miles, such as a strait, considering the draft of the vessel and water depth. The Master should assume con of the vessel on the Bridge and increase officer(s) and/or lookout(s) as required. Due to the proximity of shoal water navigation through confined waters is a high-pressure situation where a single error may lead a ship to run aground, collide with other vessel and/or damage a shore structure. After covering many miles at the ocean when a cargo ship finally arrived at a confined it is much of a different scenario.
During confined water navigation water-depth limitations will change considerably the pressure distribution around a moving vessel and will mostly cause an increase of the hydrodynamic forces due to the
ship’s motion through the water. Besides an increase in the
ship’s resistance, water-depth restrictions in general result
in a decrease of her maneuverability, manifesting itself in
the results of standard maneuvers. Besides the effects of the
restricted depth, a ship also has to deal with the vicinity of
banks, the presence of other shipping traffic, currents, speed
restrictions, and so on.
Passage planning in confined water, therefore, needs some careful considerations. For safety in navigation, shipmaster should consider following matters:
Approaching confined water
Presence / Absence of special navigational rules and items to report.
Information from the sailing directions, coast pilot, and so on.
The draft of the vessel and the navigable sea area.
The effect of squat and the need to keep sufficient under keel clearance.
Expected tides and tidal currents.
Weather conditions and countermeasures against restricted visibility.
Use of navigation aids to maintain Continuous monitoring of vessels position, such as setting of Parallel Index line or ARPA Mapping, etc.
Passing time of danger points (Daylight / Night-time)
The traffic density including the presence of fishing and the countermeasures
The vessel's maneuvering ability
Any necessity for adjustment of the vessel's speed.
While under pilotage master-pilot information exchange should include all relevant safety-critical data on the impending passage.
Increased risk of collision during confined water navigation- A brief guideline for Singapore strait
Vessels transiting through or anchoring in, the territorial waters of Singapore, including the
Eastern and Western outer port limit (OPL) anchorages of Singapore, are urged to be especially
careful in the avoidance of collisions with other ships.
Evidence points to an increased risk of collision in this area where there is a large accumulation
of vessels lying at anchor. Cargo vessel often found to be in a situation without no direct fault of own got entwined with another vessel that had dragged anchor.
It is important, therefore, while a vessel is at anchor in these areas a careful anchor watch is
maintained at all times, with the vessel’s engines being kept at short notice of readiness. Bridge
watchkeeper(s) must not be distracted from their duties by other work or duties and must
carefully monitor vessels both underway and at anchor that could pose a threat. If in doubt
regarding another vessels or intentions, the Master must be called immediately, the main
engine put on stand-by and the anchor party called to proceed forward immediately.
Singapore strait traffic
Masters should be aware that the Singapore Port (MPA) has no authority or control of the OPL
anchorages. Caution should be used in selecting a suitable location to anchor, with due regard
to the proximity of other anchored vessels, the strength and direction of prevailing tidal
currents, and the speed and direction of the wind at the time maneuvering take place. Planning
and execution of anchoring should be carried out in full compliance with local and international rules.
Maintain a good lookout and monitoring vessels in the vicinity is, of course, essential at all
anchorages and vessels must not hesitate to take action to avoid a collision, even though a
vessel while at anchor is not classed as being ‘underway’.
Traffic Separation Schemes (TSS) guideline during confined water navigation
TSS’s are frequently monitored by radar coverage by coastguard personnel, (e.g. Dover Strait). With AIS it is easy to identify vessels. Particular emphasis is therefore required regarding compliance with Rule 10 and in particular when crossing the traffic lanes within confined water. The rule requires:
"A vessel shall, so far as practicable, avoid crossing traffic lanes but if obliged to do so, shall cross on a heading as nearly as practicable at right angles to the general direction of traffic flow".
This is strictly enforced and vessel Masters have been fined in Courts for not following the guideline. It is essential that all Deck officers fully understand the requirements of Rule 10.
All passage plans must clearly show that the intention is to cross the lane at right angles or as close to as is practical. This minimizes the time a crossing vessel is in the lane irrespective of the tidal stream and should lead to a clear encounter situation with vessels passing through the main traffic lanes.
The UK MCA has issued MGN 364 which relates to the Dover Straits, however, the general separation scheme principles in Section 2 (Traffic Separation Schemes – Application of Rule 10) are equally applicable to all schemes and should be fully understood by Officers of the Watch.
ShipsBusiness.com is merely an informational site about various aspects of ships operation,maintenance procedure,
prevention of pollution and many safety guideline. The procedures explained here are only indicative,
not exhaustive in nature and one must always be guided by practices of good seamanship. User feedback is
important to update our database. For any comment or suggestions please Contact us Site Use and Privacy - Read our privacy policy and site use information. //Home //Terms and conditions of use
