13 Towed Object
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Statutory Documents - IMO Publications and Documents - Circulars - Maritime Safety Committee - MSC/Circular.884 – Guidelines for Safe Ocean Towing – (Adopted on 21 December 1998) - Annex - Draft Guidelines for Safe Ocean Towing - 13 Towed Object

13 Towed Object

  13.1 Every towed object, whether manned or not, should be assessed and provided with a confirmation of its fitness to be towed, covering all below mentioned requirements.

  13.2 The towed object should have adequate intact stability in all the loaded and ballast conditions expected during the voyage. Compliance with any applicable damage stability criteria should be verified, if not unreasonable due to special conditions. Such damage stability should be demonstrated to the extent the towed object may have been previously documented to.

  13.3 Prior to sailing, the watertight and weathertight integrity should be confirmed by an inspection of the closing arrangements for all hatches, valves, airpipes, and other openings through which water might enter the towed object and affect its stability. It should also be confirmed that any watertight doors or other closing arrangements within the hull are securely closed and that any portable closing plates are in place.

  13.4 Towed objects should be at a suitable draught and suitably trimmed for the intended voyage, commensurate with the stability condition demonstrated in accordance with section 13.2.

  13.5 It should be documented that the towed object has adequate structural integrity in relation to the cargo loads, the design environmental conditions and other foreseen loads during the voyage. Where applicable, reference should be made to the towed object's loading manual.

  13.6 The cargo securing arrangements (ref. section 6.1) and weather protection for the cargo, equipment and stores carried on the towed object should be carefully examined to ensure that they are adequate for the voyage. Where applicable, reference should be made to the towed object's cargo securing manual.

  13.7 Where applicable, a bridle should normally be used for connection of the main towing wire rope to the towed object. Chains should be used in way of chafing areas such as fairleads.

  13.8 All connection parts (e.g. each leg of a bridle) should have a documented minimum breaking load (MBL) exceeding the breaking load of the towing arrangement.

  13.9 Towline attachments should be designed to resist the towline pull from any likely direction, with use of fairleads if necessary. The design and arrangement of the towing fittings should take into account both normal and emergency conditions.

  13.10 The ultimate strength of any towline attachment (bracket or bollard and their foundation) should not be less than 1.3 times the minimum breaking load of the towing arrangement which is to be attached.

  13.11 Fairleads should be designed to accommodate the chafing chain and should be shaped so as to prevent excessive bending stress in the chain links.

  13.12 A bridle recovery system should be fitted on the towed object, strong enough to be utilised after towline breakage, in case the bridle is planned to be used again during the towage.

  13.13 Emergency towing equipment should be provided in case of bridle failure or inability to recover the bridle. This equipment should preferably be fitted at the bow of the towed object and should consist of a spare bridle or towing pennant fitted with a floating rope and buoy allowing it to be picked up without any significant hazard.

  13.14 Towed objects should exhibit the navigation lights, shapes and, if manned, make the sound signals required by the International Regulations for Preventing Collisions at Sea, 1972, as amended. Due consideration should be given to the reliability of the lights and sound signals and their ability to function for the duration of the voyage. When practicable, a duplicate system of lights should be provided.

  13.15 Boarding facilities should be rigged on each side of the towed object.

  13.16 When appropriate, the rudder should be secured in the amidships position and measures taken to prevent the propeller shaft from turning.

  13.17 Life-saving appliances in the form of lifejackets and life buoys shall be provided whenever personnel are likely to be on board the towed object even if only for short periods. When personnel are expected to remain on board for longer periods of time, liferafts should also be provided. If the freeboard is more than 4.5 m, liferaft davits should be provided, unless rendered impractical due to the design or conditions of the towed object.

Whenever the towed object is continually manned, the riding-crew should be provided with adequate supplies of food and water, cooking and sanitary facilities, radio equipment, including means of communication with the towing vessel, distress signals, life-saving and fire-fighting appliances.

  13.18 Towed objects should be equipped with an anchor, suitable for holding the towed object in severe weather conditions, that is securely attached to a chain cable or wire and is arranged for release in an emergency by persons on, or boarding the towed object, unless rendered impractical due to the design or conditions of the towed object.

  13.19 To reduce the risk of pollution, the amount of oil carried on the towed object should be limited to what is required for the safety of the towed object and/or towing vessel and for their normal operations, provided no risk to the environment will result from the removal of oil from the towed object.


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