Smit International has purchased two 28m ‘Rotor Tugs’ for use in Zeebrugge to join the fleet of tugs serving the new towage contract in the port (MJ –Towlines December 2011).

The pair will be the first ‘Rotor Tugs’ to be acquired by Smit and were almost certainly selected for their unique ability to apply all of their massive 86 tons bollard pull in any direction, making them ideal for shiphandling work in confined situations.

The tugs purchased are the RT Samba and RT Tango, originally completed by the ASL Shipyard in Singapore some months ago for German owners as the Exact and Midlum respectively. Both vessels are now on route to Europe under their own power after being dry docked, repainted and renamed in the ASL yard. The tugs left Singapore in late December as the Smit Kiwi and Smit Emoe in the hands of Transport & Offshore Service (TOS) delivery crews for the 12,700 nautical mile delivery voyage.

Smit Kiwi and Smit Emoe were built to the RT80-28 design under the supervision of KST BV of Rotterdam. The tugs are 28m in length overall and 12m beam with a draft of approximately 5.95m. Germanicher Lloyd classification includes notations for Hull to Ice Class E and fire fighting to FiFi1 standard, with self protection spray and foam.

A unique triple unit propulsion system comprises three ABC 8DZC main engines of 1,766 kW each (total 7,100 bhp), driving three Schottel azimuthing propulsion units, incorporating SRP1215 with variable pitch propellers. On trials the tugs achieved a bollard pull of over 86 tons towing both ahead and astern. The maximum speed of the RT80-28 is 12 knots ahead and astern and with the ability to side step at 7 knots.

Two identical Plimsoll towing winches are installed, one on the fore deck and one aft. Both winches have a maximum brake holding load of 200 tons and can accommodate 250m of 70mm synthetic towline or 450m of 56mm steel wire rope. The forward winch incorporates the anchor windlass and two warping heads. A deck crane with a capacity of 10 t/m is installed on the aft deck.
The tugs are classed for unmanned machinery spaces (UMS) and all engines and relevant machinery can be started and stopped and monitored from the wheelhouse. An alarm and monitoring system by Alphatechnique enables the crew to monitor the ship systems remotely. All three engine/propulsion unit controls can be operated individually or by means of a ‘Master Pilot’ system that enables the tugmaster to control all three thrusters with a single controller. The configuration of three azimuth thrusters gives the ‘Rotor Tug’ full power in any direction and spectacular manoeuvrability. It is claimed that the triple unit propulsion system installed offers a high degree of redundancy. If one engine fails, the tug is still able to operate at a useful 66% power with the two remaining engines.

Source: maritimejournal.com