Three important lessons have emerged from the investigation into the capsize of the tug Adonis at Gladstone, Qld on 11 June 2011 says Australia’s Transport Safety Bureau, ATSB: Masters of tugs, regardless of size, need to be actively aware of the signs that a tug might be in danger of capsizing and what to do to lessen this danger; In multiple tug operations, masters need to plan the passage and consider the speed of the passage and when it is time to release the towline; It is also essential that masters communicate frequently throughout the passage bring any concerns about speed to the other master’s attention.
On 11 June the harbour tug Adonis, which had four persons on board, was engaged in an operation with a second tug, Wolli, to move an Australian registered unmanned steel flattop dumb barge (Chrysus) in the port of Gladstone, Queensland. Adonis capsized during the operation. Three of the four persons on board escaped but the fourth drowned in the wheelhouse.
The tug’s crew were not able to release the towline using the towing hook’s quick release arrangement before the tug capsized.
The ATSB found that while the masters of the two tugs were aware of the risk of capsize, neither of them realised that Adonis had entered a classic capsize scenario when it moved abaft of the barge’s port bow before the barge had begun to slow down. The barge’s speed was not reduced in time to allow Adonis’s master to regain control of the tug and manoeuvre it back into a safe position ahead of the barge. The tug’s crew were not able to release the towline using the towing hook’s quick release arrangement before the tug capsized.
Investigations into the accident found that the retrospective fitting of a set of ‘H’ bitts to the tug aft of the towing hook had a detrimental effect on the tug’s manoeuvrability. The fitting of the ‘H’ bitts and a towing winch also resulted in Adonis being unstable when undertaking towing operations over the stern. This fact was never identified by the tug’s owners because the tug’s stability was not recalculated after the fitting of the additional equipment.
Sea Swift, the owners of Adonis, have produced new procedures covering the quick release arrangements on its tugs and enhanced the training and familiarisation of its crews with these arrangements. The company has also reviewed all of its tugs’ towing and quick release arrangements and introduced regular testing of the equipment. They have also implemented a program to review all stability data for tugs purchased overseas. Sea Swift has also employed an experienced training manager to review and monitor the company’s health and safety practices. A review of Sea Swift’s training assessment for new masters has extended the period of training to include mentoring and supernumerary runs with other masters to develop a greater understanding of towing requirements.
Podcast: The Case of the Toppling Tug