Twiflex VKSD-FL Spring-Applied Brakes for Vessel Mooring Winches
Twiflex Ltd., along with their partner Intertech b.v., recently supplied brakes to a major offshore winch manufacturer based in the Netherlands for use on ship-to-ship mooring winches. The brakes are used on the winches to limit tension in the towing cable and are required to slip briefly if the peak loading condition is exceeded.
Twiflex VKSD-FL (floating) spring-applied, hydraulically-released brakes were supplied, each rated at 119 KN braking force for a 2mm pad air gap. The brakes were designed to produce over 2 million cycles (spring fatigue life) and feature a unique ‘parked-off’ system (i.e. they can be adjusted under hydraulic pressure so that when pressure is removed there is no stored energy making the unit completely safe during pad changes or maintenance).
During towing operations, if the tow cable tension is greater than 30 tons, due to the action of the waves between the two vessels, the brakes slip to protect the winch and cable. If the load is below 30 tons the cable is reeled in. The operation repeats itself (in bad weather) several times until the ship is alongside.
Each of the two onboard winches utilize VKSD-FL brakes acting on a 1500m dia. x 40mm thick extended drum flange (stainless steel) with a total braking capacity available of 234 kNm. The brakes are actively controlled and monitored by the customer’s hydraulic system which regulates back pressure to ensure the desired torque is achieved.
All equipment was supplied fully prepared for marine use (EN plate) with external surfaces painted to ISO 12944-5 : 2007 – C5 in signal red RAL3001 to meet the customer’s specification.