Newbuild ASD tug enhances towage, reduces emissions

Portland Harbour Authority has advanced its towage capabilities in southern England with the addition of a newbuild azimuth stern drive (ASD) tugboat from Damen Shipyards.

Wyke Castle joined the small operating fleet in Portland Port in April 2025 after its construction by Damen at its shipyard in Changde, China, to an ASD 2111 design.

This 198-gt, 21-m tug has a beam of 10 m and two Caterpillar main engines connected to selective catalytic reduction (SCR) units to minimise NOx emissions and comply with IMO Tier III standards. Wyke Castle has a top speed of around 12 knots, and 50 tonnes of bollard pull. It was one of the first ASD 2111 tugs brought into service after Damen introduced the new design.

According to Portland Harbour assistant harbour master Dan Taylor, this newbuild tug was required to lower emissions while keeping three tugs available in the port ready to support large naval and merchant ships in challenging environmental conditions.

This new tug also reduces emissions in the harbour. “Damen’s own SCR system fits into a smaller package, resulting in 75% less NOx. depending on operations, we can get an 82% reduction of NOx on each engine,” he tells International Tug & Salvage.  

“The nature of our operations and distant voyages puts the SCR through its paces.”

To make room for Wyke Castle, Portland Harbour sold 2006-built, 329-gt Rufus Castle. The 28-m tugboat was renamed Excalibur and is now operating in Brindisi, Italy, according to automatic identification system information.

Wyke Castle has a winch below the wheelhouse with access for towage over the bow or stern, plus a small deck crane for equipment handling and a Furuno radar and navigation suite.

Portland Harbour operates two other tugboats, 2019-built ASD vessel Rupert Best and 1993-built ASD tug Maiden Castle, which will work alongside Wyke Castle on ship towage and manoeuvring, Mr Taylor explains.

Rupert Best has an overall length of 22 m, a beam of 11 m and a bollard pull of 50 tonnes. It was built by Sanmar Shipyards in Turkey to a Robert Allan design. Maiden Castle is a 31-m tug with a beam of 10 m and a bollard pull of 55 tonnes.

Ships requiring assistance from one of these tugboats need to provide six hours’ notice to Portland Harbour, and if two tugs are required, shipowners must give 12 hours’ notice.

Portland Harbour welcomes a diverse range of vessels, including cruise ships and naval auxiliary ships. The weather and sea conditions can be challenging, with tidal flows and wave heights of 4 m regularly recorded in the bay.

To man this fleet, Portland Harbour has four tug masters plus one on standby, four engineers and two marine officers, and there is a pool of casual crew that can be called in, says Mr Taylor.

Training is undertaken at simulator centres in Cosham and Portsmouth, UK, with courses run by Seaways Global, including tug master and engineering studies.

Portland Port was privatised and taken over by the Langham Group in 1996, and the Portland Harbour Authority later took over as the statutory harbour authority in 1998. Portland Port is responsible for the dock estate and business.

Portland Harbour offers a range of marine services including cargo handling, vessel berthing and logistics support. Pilotage is supported by a team of maritime pilots and two Interceptor 42 class transfer vessels, 2007-built Culverwell and 2009-built Rodwell, each with an overall length of 13 m, a top speed of 25 knots and an ORC 121 fast pilot vessel built by Goodchild Marine.