The Royston treatment for Caledonian tugs

With a global presence and history dating back many years, Newcastle upon Tyne-based Royston is an instantly recognisable name in marine engineering, particularly in the tug sector and being an authorised Niigata and Yanmar agent was well placed to carry out work on Caledonian Towage’s tugs Strathdon and Strathdee both of which originate in Japan.

Work was carried out during docking in Peterhead and involved inspection, overhaul and servicing of main and auxiliary engines, associated components and both azimuth thrusters. Royston’s original equipment manufacturer trained teams carried out the work involving dismantling, inspection and engine refurbishment tasks, work including unit inspection of both Niigata main engines, top end overhaul of the auxiliary engines and complete overhaul of the harbour set.

The Z-Peller units were overhauled as per manufacturer guidelines, including inspection and renewal of propeller shaft seals along with inspection and measurement of clearances for both gearboxes. In Royston’s workshop, cylinder heads, fuel injectors and fuel pumps were dismantled, cleaned and inspected for signs of wear or damage with repair and part replacement work carried out where necessary. With the work completed on schedule and following satisfactory sea trials both vessels returned to service with Caledonian Towage.

Strathdon and Strathdee are rare examples of a recognisable design of tug common in the Far East that have found their way in small numbers to European waters. Built in Japan in 2006 by Kanagawa Dockyard, Kobe for Japanese owners as Azuma Maru and Iida Maru respectively they have followed similar careers operating for JP Knight Ltd/Knight Caledonian Ltd then Caledonian Towage Ltd as Keverne and Kintore before taking up their current names in 2014.

Capable of both harbour and offshore towing duties the near-sisters have a length of 32.5m and breadth 11.4m. They are powered by Niigata 6L28HX main engines producing 3,310kW (4,500bhp) in total powering Niigata ZP-31 five-bladed azimuth thrusters in ASD configuration. Yanmar supplied the auxiliary engine and harbour generator and performance figures include 65tbp (ahead) and speed 13kn. Two fire monitors are provided on the bridge deck with 80t brake Marine Hydrotec rope and wire winches installed forward and aft, along with a 3t lift Palfinger crane aft.

By Peter Barker