Schottel celebrates ten vessel order

When considering US-designed tugs, built in US-owned shipyards for US owners it is easy to overlook that major and minor components are sourced on a global basis. European manufacturers are particularly active here and Schottel typifies the theme with ten US-built and owned terminal and escort tugs benefitting from its Rudderpropellers along with Vulkan’s Safeguard Basic driveline protection system.

The ten vessels are under construction at Gulf Island Fabrication in the US, the first three Mark E Kuebler, Ted C Litton and Connelly M now delivered to Bay Houston Towing Co. Each of the Robert Allan Ltd-designed Z-Tech 30-80 tugs are equipped with Schottel Rudderpropellers type SRP 510 FP along with the Vulkan system designed to issue early warnings when intervention in the propulsion drive train is required.

Propulsion is via Caterpillar main engines providing performance figures of 13kn and 81.5tbp and 100t steering force at 10kn in escort mode. Safeguard Basic, developed by Vulkan Couplings has a key role in the system, detecting torque loadings as a function of the twist angle via torque-transmitting components such as composite shafts. Data is analysed and evaluated using pre-set warnings and alarms. With an interface to Schottel’s control system, optical warnings and audible alarms indicate when intervention is required by the master with a response time of around 80ms.

The system has ABS approval as both monitoring and safety equipment and can be supplied as an integrated Schottel/Vulkan system or refitted to vessels already with Schottel Rudderpropellers.

Propeller nozzles are now virtually universal as an integral component with both fixed shaft-line propellers and azimuthing thrusters on tugs. Their design is critical however in extracting maximum focused thrust while also providing maximum efficiency and Schottel has introduced a new high-performance nozzle, the SDC40.

The nozzle sets “new standards in terms of compact design and free-running efficiency”, it also stands out with its optimally designed propeller geometries and comes equipped with Schottel’s patented ProAnode as standard and available for all Schottel Rudderpropellers. Optimised by means of CFD the nozzle is characterised by its small outer diameter and suited for conversions with limited installation space and offers improved free-running efficiency during transits at higher speed.

By Peter Barker