Did fuel switch cause Houston collision?

Malcolm Latarche
Malcolm Latarche

21 June 2016


Earlier this month the US maritime safety authority the National Transportation Safety Board (NTSB) issued an interim report into the collision in March 2015 in the Houston Ship Channel between the bulker Conti Peridot and the chemical tanker Carla Maersk that resulted in a major spill of the hazardous chemical methyl tert-butyl ether. The accident occurred in dense fog and resulted in some $8.2m damages to the two vessels as well as a safety alert to local residents. The report says the collision occurred after the pilot on the Conti Peridot was unable to control the heading fluctuations that the bulk carrier was experiencing during the transit. As a result, the Conti Peridot crossed the channel into the path of the Carla Maersk. The NTSB determined that the probable cause of the collision was the inability of the pilot on the Conti Peridot to respond appropriately to hydrodynamic forces after meeting another vessel during restricted visibility, and his lack of communication with other vessels about this handling difficulty. Contributing to the circumstances that resulted in the collision was the inadequate bridge resource management between the master and the pilot on the Conti Peridot. The report (which is subject to revision) does not mention any other major issues and recommends that the owner of the bulker informs its personnel of the circumstances of the accident and requires training and audit procedures to ensure that bridge resource management is practiced during all operations and for the Houston Pilots Association to inform its members about the need for effective bridge resource management and timely communication between pilots when circumstances could impact the safety of vessel operations. However, it seems that the pilots believe that other factors were at play and the real cause of the incident was a loss of power on the Conti Peridot due to a switch over to low-sulphur fuel. According to a regional newspaper the Houston Chronicle, the pilots will be contesting the report and quotes the pilot on the bulker as saying the ship was known to be difficult to handle under the normal circumstances and had handled sluggishly during the transit – and that he lost speed just before the collision, even though he had ordered more turns on the propeller. The pilot blames a switch to ultra low sulphur fuel for the engines for the loss of power. The issue of loss of power during fuel switchovers is a well known hazard and one that the USCG has issued a number of safety alerts over. The most recent issued in late 2015 recommended that as part of the master pilot information exchange, vessel owners should discuss the vessel's manoeuvring characteristics, including any change in RPM associated with ultra low sulphur fuel oil and shipowners should also determine if the use of ultra low sulphur fuel oil necessitates amendments to the pilot card. The USCG is apparently investigating a number of loss of power incidents in the Houston Ship Channel where the number of collisions doubled from seven in 2014 to 14 last year. In addition, over the last three years around 60 vessels per year have reported loss of power in the Houston Ship Channel. It is for the US authorities to determine the true cause of the incident and to ascertain if the fuel switch over did indeed contribute to the incident but the fact that it has been raised as such by the pilots involved would suggest that more attention needs to be paid to the issue by all vessels needing to switch fuels in any part of the globe.