Mark E Kuebler was built by Gulf Island Shipyards to an adapted Robert Allan Z-Tech design for escorting large ships in the US Gulf
The first of a series of 10 highly anticipated green escort tugs has been delivered to a US Gulf tug owner by Gulf Island Shipyards. Mark E Kuebler is one of the first escort tugs built to the highest emissions standards in the US.
It was designed by Robert Allan and built to ABS class and US Coast Guard regulations for escorting large ships using terminals on the US Gulf coast. Mark E Kuebler complies with the Environmental Protection Agency (EPA)’s Tier 4 emissions requirements, which restrict sulphur and nitrogen oxides in the exhaust. It was also built for fire-fighting and emergency response duties.
Gulf Island Shipyards built the Z-Tech 30-80 design tug at its shipyard in Galveston, Texas at the end of 2018. Mark E Kuebler has started operations for Bay Houston Towing Co, through its operator G & H Towing Co in Texas.
The original contracts for this series of escort tugs were signed in May 2017. In May 2018, Gulf Island Shipyards renegotiated these contracts, adding two more tugs to the orderbook. Of the 10 on order, five are to be built for Bay Houston Towing Co and another five for Suderman & Young Towing Co.
Mark E Kuebler has an overall length of 29.5 m, moulded beam of 13 m and moulded hull depth of 5 m. Robert Allan said the hull design had evolved from Z-Tech 7500 design for escort tugs. It incorporated the sponsoned hull form from its RAstar series of tugs into the Z-Tech design.
Naval architects then used computer simulations and computational fluid dynamics to adapt the design for higher escort performance. Robert Allan expects this series of 10 tugs to have 100 tonnes of steering force at 10 knots, which is particularly important for escorting large ships.
Mark E Kuebler is classed by ABS with notations for towing, escort and fire-fighting duties. During sea trials it achieved a free running speed of 13 knots and bollard pull of 81.5 tonnes.
Its main propulsion comes from a pair of EPA Tier 4 certified Caterpillar 3516E engines that generate 2,525 kW at 1800 rpm. These drive Schottel SRP 510 fixed pitch Z-drive units with 280-cm diameter propellers.
Electrical plant on this Z-Tech 30-80 tug consists of two John Deere 6068AFM85 diesel generator sets, each with a three-phase power output of 125 kW, 480 V and 60 Hz.
Mark E Kuebler is fitted with a FiFi1 fire-fighting system with two pumps supplied by Fire Fighting Systems with capacity of 6,200 gallons per minute driven by two Caterpillar C18 engines.
Its vessel handling fenders include 41-cm thick double loop soft fenders between the main deck and the knuckle at bow and along the sheer lines of the main deck. Plus, there are 91-cm diameter cylindrical fenders at the main deck level of the bow and 41-cm diameter cylindrical fendering at the stern.
Mark E Kuebler’s accommodation includes a galley and a mess, plus single cabins for the master and chief engineer on the main deck and two double cabins for four crew members on the lower deck. The tug can store 195 m3 of fuel oil and 30.5 m3 of potable water.
Mark E Kuebler particulars
Owner: Bay Houston Towing
Shipbuilder: Gulf Island Shipyards
Designer: Robert Allan
Design: Z-Tech 30-80
Operating area: Texas, US
Bollard pull: 81.5 tonnes
Length, oa: 29.5 m
Beam, moulded: 13 m
Hull depth, moulded: 5 m
Free running speed: 13 knots
Main engines: 2 x CAT 3516E
Propulsion: 2 x Schottel SRP 510FP Z-drive