Adsteam Shotley is virtually identical to the previous three tugs of this type delivered to Adsteam. The tug has an overall length of 24.55m, a beam of 11.49m and maximum draft of 5.40m. Substantial fendering is fitted, with particular attention being given to the bow and ‘shoulders’ where most heavy contacts take place while working in the ‘push-pull’ mode. Fendering and the carefully designed ‘clearance’ built into the superstructure and funnels is essential in a port such as Felixstowe where the majority of work is handling containerships with a large flare at bow and stern.

Power for propulsion is generated by two Caterpillar 3516B TA HD/D main engines producing a total of 5,592 brake horsepower at 1,600 rev/min to drive a pair of Rolls-Royce propulsion units. Unlike previous tugs of this type, the azimuthing propulsion units incorporate a ‘built in’ slipping clutch unit, obviating the need for a separate proprietary unit mounted in the driveline. On trials the tug achieved a bollard pull of approximately 69 tons ahead and 64.0 tons towing astern with an almost identical free running speed of 13.1 knots ahead and 13.0 knots astern. The high degree of agility demonstrated by the vessel, and its handling characteristics going astern and during shiphandling, are impressive.

As with all vessels of this design, Adsteam Shotley is a very quiet tug, benefiting from resiliently mounted engines, flexible drive couplings, heavily lagged silencers and sound proofing insulation in the floors and ceilings.

Adsteam Shotley tows over the bow when shiphandling from a hydraulically driven, split drum, Kraaijeveld winch and combined anchor-windlass on the foredeck. The two-speed winch has a line pull of 18 tons at 11 m/min and a brake holding load of 150 tons. A ‘brake force’ limiter is fitted in the hydraulic system of this vessel allowing the winch drum to ‘render’ at a preset load but no provision is made to ‘recover’ automatically. No deck machinery has been fitted aft and the only provision to tow astern is the mounting of a substantial, centrally located towing post.

A typical Damen style wheelhouse has a single control position at the forward end for the tugmaster, seated between the two main units of a ‘split’ console, with the propulsion unit/engine speed controllers on each side of the console in the usual way. The winch controls are also located and easily accessible on the left console. A full outfit of navigational and communications equipment includes two Furnuno FR-1505 Mk III radars, GP-90 GPS and FE-700 Echosounder. Two Sailor RT 4822 VHF (with DSC) and one Sailor RT 4800 radios are fitted, along with a Furuno Navtex NX-500 and two Jotron TR-20 VHF GMDSS approved handsets.

Adsteam Shotley is a welcome addition to the local four tug fleet.

By JACK GASTON