In line with the Nationwide Transportation Security Board (NTSB), an uncrewed basic cargo vessel sank on March 6, 2022, throughout a towing operation close to the Magallanes Financial institution, roughly 25 nautical miles northwest of Santo Domingo Cay, Bahamas. The incident occurred whereas the vessel was being relocated underneath tow. No accidents had been reported.
What Occurred
On March 3, a towing vessel departed the Port of Miami, initiating a four-day useless ship tow of a basic cargo vessel certain for a shipyard in Haiti. The towed vessel had been laid up for 2 years and was in visibly poor situation on account of an absence of upkeep. It was linked astern utilizing a 2-inch wire rope tow line roughly 1,000 ft lengthy, hooked up to a Spectra bridle and chafing gear routed by way of deck fittings.
By midnight on March 6, the tow was progressing at 4.2 knots in sea situations close to the operational limits outlined within the authorised tow plan—winds of 24–30 knots and waves of seven–9 ft. At 0035, the towing vessel’s mate reported listening to a loud noise adopted by elevated pace, indicating that the towline had parted.
The crew noticed that the cargo vessel’s port anchor chain had deployed, and the ship was sitting decrease on the stern. Regardless of tough situations, they resecured the tow by reconnecting to the remaining portion of the bridle and continued slowly underneath tow. By dawn, the towed vessel appeared trimmed additional by the strict.
At 07:20, the mate boarded the cargo vessel and found the engine room was flooded above the principle engine. Makes an attempt to dewater utilizing a transportable pump had been unsuccessful. By 15:00, the ship started to record to starboard, prompting the crew to arrange for its imminent sinking.
At roughly 15:20, the mate departed the vessel. The towing crew launched the complete size of the tow wire earlier than chopping it to take care of distance. At 16:20, the ship sank stern first in 3,300 ft of water, taking the towline and bridle.
Why It Occurred
The NTSB decided that the possible explanation for the incident was uncontrolled flooding of the engine room from an unidentified level beneath the waterline. Contributing components included the poor materials situation of the vessel, the deployment of the port anchor, and elevated hydrodynamic drag from the vessel’s deeper draft. Mixed with dynamic loading in heavy seas and excessive winds, these components positioned extreme stress on the towline system.
Actions Taken
The tow plan had specified operational limits for sea state and wind situations. Whereas these situations had been approached however not exceeded, the crew adopted procedures by trying to resecure the tow and deploying dewatering gear—ultimate actions concerned safely distancing the towing vessel earlier than the tow was severed.
Classes Realized
Vessels scheduled for useless ship tows ought to endure thorough situation assessments to determine vulnerabilities, notably beneath the waterline.
Towline preparations should account for dynamic masses in marginal sea situations.
Pre-deployment of emergency gear, resembling dewatering pumps, is crucial, however their capability ought to match worst-case situations.
Steady analysis of vessel situation throughout tow operations is crucial, particularly after line failures or surprising vessel behaviour.
Operational limits in tow plans must be handled conservatively when the vessel situation is questionable.
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Supply: NTSB
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