Marine pollution is a global challenge and mineral-based product spills, such as heavy oil, marine diesel oil, lube oil and hydraulic oil, not only pose a fire and safety risk on board vessels, but may cause immense environmental damage if allowed to escape into the sea, says marine services provider Smit Amandla Marine salvage master Captain Ian Carrasco.

“Hydraulic equipment, such as that used in steering gear systems, mooring winches, deck cranes and controllable pitch propellers to name a few, which uses hydraulic oil as a noncompressible transport medium within a closed circuit to operate the equipment under pressure, is used extensively on vessels.”

Provided the hydraulic oil remains in a closed system on board with no leaks from pipe work, flanges and pump motors, the risk of pollution is mitigated, Carrasco notes.

He stresses that it is imperative for engineers on ships to ensure that mineral-based oil products are contained in a closed environment to prevent unwanted pollution.

Hydraulic oil, if not stored in dedicated tanks on board ships, is stored in 210 ℓ capacity drums, which need to be securely fastened and carefully transported to and from the quayside to prevent spillage.

He explains that hydraulic oil is a refined petroleum product and, if allowed to escape into the sea, will enter the water column and harm sea and bird life, as it does not break down easily.

However, environment-friendly hydraulic oils which are less harmful to the marine environment, are available at a higher cost.

Carrasco, who is an experienced Master Mariner, reveals that shipboard pollution in the maritime industry is regulated by the International Convention for the Prevention of Pollution from Ships (Marpol 1973, as modified by the 1978 and 1997 protocols), to which South Africa is a signatory.

“The maritime industry is well regulated for all types of pollution and heavy fines are levied against those ships that do not comply with the regulations set out by the Marpol Annexes 1 to 6.”

Carrasco notes there are many substandard ship operators that manage their vessels on a limited budget.

Worldwide, State port control authorities, such as the South African Maritime Safety Authority, are required to inspect and detain ships that do not comply with international standards and prevent them from departing port until the deficiencies are corrected.

“Not all ships can be inspected and there are those that slip through the net. In these instances, the likelihood of an incident occurring is significantly increased if the ship is old and there has been insufficient maintenance, for example on machinery, which plays a considerable part in incidents occuring,” he emphasises.

Carrasco states that all accidents are preventable, but notes that human error plays a significant role in the many instances of ships running aground worldwide each year. “The maritime industry does its best to regulate and maintain high safety standards.”

High standards are set for crew competence under the International Convention on Standards of Training, Certification and Watchkeeping for Seafarers and the design and strength of ships, which should be built according to internationally recognised Classification Society standards, such as Lloyds Class, Bureau Veritas and the American Bureau of Standards.

He points out that, of the many ships that run aground worldwide each year, some do so on South Africa’s coastline, which is notorious for huge seas and ‘freak’ waves that have been reported in adverse winter weather conditions, emanating from the Deep South.

A recent example of a ship running aground is the incident on May 12, in which long-line fishing vessel Eihatsu Maru ran aground at Clifton’s First Beach, in Cape Town. It was refloated by Smit Amandla Marine on May 18, successfully avoiding marine pollution from onboard pollutants by ensuring a fast response time and a fuel removal operation prior to the refloating, says Carrasco.

“The longer a vessel remains aground without assistance from specialised salvage companies, the bigger the threat of pollution to the marine environment.

“The chances of refloating a grounded ship successfully diminish with each passing hour, owing to environmental forces, such as sea swell, currents, tidal effects and reduced water depth, impacting on the structural integrity of the ship.”

Carrasco points out that when a vessel runs aground, the first priority is to get the non- essential crew safely ashore. The next consideration, depending on the circumstances, is to remove the bunker oil as there is a risk that the fuel tanks could become breached on refloating, especially if the sea bed is rock or coral. On the many groundings that have occurred, engine spaces have become flooded. The polluted water often contains heavy oil, diesel oil and hydraulic oils that escape from fuel tanks, machinery and equipment to the surface of the water.

“This oily water mixture has to be pumped or skimmed off the surface by the salvage team and pumped to reception facilities. The oily mixture should be contained on board to prevent the consequences of any unwanted spillage to the marine environment.

“To remove oil from the oily water interface is a labour intensive and costly process,” Carrasco stresses, referring to the Seli 1 vessel that ran aground off the Milnerton coastline, in Cape Town, in 2009.

“The wreck was not removed and authori- ties are still trying to clean up the escaping oil on the beaches as the vessel is breaking up through wave action,” he adds.

The cost of removing a stranded vessel, together with all the marine pollutants and cargo, from the coastline by cutting it up is prohibitive, owing to the extent of the specialised work, the equipment required and the high risks involved, Carrasco emphasises.

To subscribe to Engineering News's print magazine email subscriptions@creamermedia.co.za or buy now.