The company has just commissioned the second of a pair of sister tugs based on sound traditional deep sea towing principles but embodying an impressive inventory of modern technology and equipment. Delivered in August and named ‘Cochise’, this latest vessel is 30.48m in length overall, with a beam of 10.67m and draft of 5.18m. Cochise and sister ship ‘Mikiona’, completed a year earlier, were both built by J M Martinac at their Tacoma shipyard.

The double chine hull form and propulsion machinery was selected with long-range towing and fuel efficiency in mind. Using particular 87,000 barrel, oil barges as the benchmark, Sause Bros aimed for maximum fuel efficiency at a towing speed of 9 knots. The choice of propeller-nozzle design, main engines and winch along with towline and rudder forces, were all designed to meet that criteria. Due to the long periods such vessels spend at sea, considerable effort also went into improving crew comfort by reducing noise and vibration and improving operational efficiency and safety.

Cochise and its sister are powered by a pair of MTU/Detroit 16v-4000 diesel main engines each downrated to 1,875 bhp at 1,600 rpm. Power is transmitted via Reinjtes gearboxes and Mather shaft brakes to three blade skewed propellers. In order to achieve the required shaft line and maximise the water flow to the propellers from the chosen hull form, the propeller shafts are over 11.5m in length. The propellers rotate within Nautican nozzles fitted with stators, and a Nautican quadruple linked rudder system was also chosen. This propulsion system produces a bollard pull of 130,000 lbs (65 US short tons), and a fuel consumption of 3,200 gallons per day whilst towing a loaded barge at 9 knots.

Dedicated tanks can accommodate 125,000 gallons of fuel oil, 10,500 gallons of drinking water and 1,790 gallons of lubricating oil.

Sause are using Norwegian built Rapp Hydema towing winches in a number of their deepsea tugs. The model installed in Cochise is a single drum, hydraulically powered, computer controlled, machine carrying a 3,000 foot, 2 ¼” steel wire towline. Automatic spooling gear is fitted to the main drum, together with a ‘gypsy head’ and an 11 ton capacity tugger winch. Hydraulic power for the winch system is produced by a power pack driven by a dedicated John Deere diesel. The winch can operate in a render and recover mode that allows the tug master to set parameters for line tension and towline length, thus reducing shock loading on the towline and reducing the need for heavy chain bridles. A continuous computerised display of winch and towing data is available in the wheelhouse and ship’s office.

Other deck equipment includes a separate bridle winch with a 1,000 foot wire hawser mounted beneath the main winch, a capstan, four hydraulically operated towing pins, a stern roller in the after rail, and a small towing winch on the foredeck. The latter carries 200 feet of manmade fibre towline to assist when the tug is working alongside its barge.

The wheelhouse aboard Cochise is equipped with navigational and communications to the high standard required for deepsea operation and a small additional high level bridge is also provided for additional visibility when needed. Among the items provided are Furuno radars, AIS, Navtex and Satellite compass, a Trimble GPS, Con/Nav autopilot, Datamarine echosounder and ICOM/SEA radios.