Comprehensive statistical material shows that grounding under power is the most frequent accident for ships calling at ports and terminals. In order to minimize the probability of such grounding under power, emergency steering is crucial.Many of the severe tanker accidents could have been avoided by the use of adequate tug escort able to perform such emergency steering.It is acknowledged that tug escort is the single most effective mean to reduce risk of ship groundings during passages through confined waters.The Oil Companies International Marine Forum (OCIMF) has published Recommendations for Ship’s Fittings with Reference to Tugs and other High Load Operations. These recommendations address the fact that in order to withstand the steering pull from the towline of a high performance escort tug, vessels require sufficiently solid ‘strong points’.IMO has issued guidelines for a ship’s own manoeuvrability (IMO 751-10/10 zigzag). Seen in relation to DNVs Tug Escort Class Notification these are standards for the necessary capabilities of an escort tug.
IMPORTANT NOTE FOR TANKERS WITH LOA 250 MTRS OR MOREFor Bosphorus strait, Istanbul Traffic Control Station permits only 1 (one) tanker with LOA 250 meters or more to transit Bosphorus Strait between 05.30 and 07.30 hours. The first one on turn is chosen for transit. Tankers waiting in turn are only permitted to transit if they take an escort tug boat for passage, otherwise they are instructed to wait at the outside of Bosphorus until next daylight.