Durban - Concerns that fast-tracking the training of harbour pilots may have contributed to recent quayside crashes in Durban were unfounded, Transnet said on Friday.

Transnet National Ports Authority chief executive, Richard Vallihu, was speaking on Friday on the sidelines of the launch of Durban's newest tug, the locally built Umbilo. Vallihu said boards of inquiry were scrutinising the two incidents, which together caused millions of rands in damage.

The Mediterranean Shipping Company's vessel, the Benedetta, struck a gantry crane at the container terminal, the Mercury newspaper reported this week, while on April 30, the bulk carrier Julian smacked into a ship loader while berthing at Bulk Connections on the Bluff. Damage in the first incident was estimated at about R100 million.

On both occasions, pilots were aboard the vessels, as is mandatory. But Vallihu pointed out that in the Benedetta crash, "one of the most experienced pilots – he is near retirement" was on duty. The port authority has in recent years made it a priority and invested in training a new generation of harbour professionals, including pilots. And Vallihu said concerns over competency were "not an issue".

On the port authority's support for South African shipbuilders, Vallihu said they would like to see the local industry moving beyond being assemblers – "hewers of wood and drawers of water" – to doing more of the hi-tech work. The control and propulsion systems, on tugs, for example, accounted for more than 50 percent of their value but were imported, he said.

South African technical know-how needed to be harnessed and specialist overseas suppliers needed to come into the country to develop the industry, he said. Umbilo, which is named for the Durban river, was built by Southern African Shipyards for the authority and its home port will be Durban. It is the sixth tug completed by the Bayhead company as part of a R1.4 billion order for nine tugs.

EThekwini mayor Zandile Gumede cracked a bottle of sparkling wine on the Umbilo at a traditional naming ceremony before a floating drydock took it into a harbour channel and began lowering it into the waters. She told guest she was delighted to see a woman among the tug's officers and said the vessel was a symbol of radical economic transformation.

Umbilo was expected to begin duties soon, easing pressure on Durban's existing tug fleet. Vallihu said: "Over the past few years, Durban has seen larger vessels calling at the port. This has put a strain on our marine fleet. Currently the port has a total of eight tugs of which four are old shuttle tugs with only 32 and 38 ton bollard pull power."

The 31 metre-long Umbilo can muster more than 70 ton bollard pull – enough muscle to push or pull the world's biggest ships, said Southern African Shipyards chief operating officer Louis Gontier. The company was expected to deliver the last of the nine tugs in early 2018. The tugs are being built over three and a half years, as part of a wider fleet replacement programme that includes dredging vessels and helicopters.

Gontier said the port authority was getting a "first class product", in quality and price, and said the company "could easily build" the country's next dredger if it were awarded the contract. Royal IHC in the Netherlands supplied the port authority's last dredger. The Mediterranean Shipping Company were contacted for comment on the Benedetta incident but this was not immediately forthcoming.