When a large new vessel is put to sea, it is usually equipped with a tunnel thruster that acts as a side propeller system to enhance manoeuvrability at berth and in open waters.

Tunnel thrusters, sometimes called bow thrusters, provide captains with increased control and can help to quickly turn a ship around.
Brunvoll AS is a global manufacturer of seaworthy motion systems with headquarters in Molde, Norway. The company has supplied more than 8000 complete side propeller systems mounted on more than 5000 different cruise ships, supply boats and navy vessels.
Machining of the side propellers, which are manufactured from nickel-aluminium bronze alloy, is conducted by the company mostly unmanned and at night. This demands a highly accurate and dependable machining process and cutting tools. Here, the versatility of Dormer’s Red Shark tap allows it to be used at different torque levels, such as when threading the propeller at the attachment to the rotor. To ensure optimal productivity and safety, the unmanned machines are slowed to a cutting speed of 25 m/min (the ideal cutting speed in the nickel-aluminium bronze is 35 m/min). However, in tests, Brunvoll ran the Red Shark up to 50 m/min – exactly double the required rate.
The Red Shark is one of several material-specific taps available from Dormer Pramet. Each tap features a colour ring on the tool shank denoting material suitability, promoting quick and easy tool selection. Dormer Pramet is set to add more tools to its assortment of Shark Line taps. This includes a range of yellow-ring taps for structural, carbon and low-alloy steels, and blue ring for stainless steels.
For further information www.dormerpramet.com