The Chittagong Port Authority’s (CPA) outer anchorage is very congested with vessels arriving at the anchorage for lighterage operations before entering the river. Entering the river can in itself be challenging due to strong currents especially during the monsoon season (June to November) when the weather conditions can deteriorate with little or no advance warning.
The Club refers to a recent incident happened at “A” anchorage, which is the northernmost anchorage designated for vessels with a draft of over 10 metres. The anchorage area is surrounded by shallower waters restricting the area available to such vessels. This is also coupled with high traffic density and strong local currents.
Following analysis of the incident and with the assistance of Coast to Coast P&I Services Ltd., Bangladesh, the Gard recommends:
Clearance from other vessels when anchoring
When anchoring close to other vessels in the vicinity, consider the time it will take before making contact with another vessel should your vessel drag anchor. This calculation is as critical as the swinging circle as it will determine how frequently the OOW should monitor the vessels position. Estimating the time required before making contact or running aground for different ground speed during dragging of anchor is an important part of the anchor watch for this particular anchorage.
Main engine readiness
When anchoring in congested anchorages, the state of readiness of the main engines is important. We have seen from a number of incidents that the main engine often comes into operation too late to avoid a collision or grounding. The usual dragging line at Chittagong anchorage is reportedly 160oto 340oand drift can be 8 knots or higher during spring tides. The tidal effect can be more pronounced when freshets are expected. Freshets are caused by the normal velocity of flow of an ebb tide augmented by the flow of an additional volume of water draining into the river from the catchment areas. In such situations the vessel cannot rely on the anchor’s holding capacity only. Vessels with 49,184 tons displacement with 9 shackles with a high holding power anchor, in depths of 12.4 metres are known to have had to place their engines on slow ahead (8.0 knots) to be able to hold their position during a spring ebb tide.
A number of vessels calling Chittagong need to lighter before being able to enter the port due to draft restrictions. Lighter vessels which come alongside the mother vessels are tied to the mother vessel using the lighter vessel’s mooring lines. Sufficient fendering must be in place between the two vessels to avoid any hull damage to either of the vessels during lighterage operations. Lighter vessel are known to have fendering arrangements consisting of old mooring ropes wrapped around wooden spars or second hand tyres. If the master is of the view that the fendering is inadequate, he should refuse the lightering vessel permission to come along side. Alternatively, the master should also consider using the vessel’s own fenders.