‘Second generation’ towing pins popular
WK Hydraulics BV of the Netherlands drew upon more than 37 years of experience in the field of hydraulic steering gear systems and hydraulic applications when designing its new ‘second generation’ towing pins.
The company started supplying towing pin/stopper systems in the late nineties, focusing on small to medium size tugs and workboats and providing dedicated functionality for limited space in the aft peaks of vessels with bollard pulls up to 80 tonnes.
In 2010, the new management of WK Hydraulics took the opportunity to start a total redesign of the company’s ‘3 in a row’ concept. The main goals for the new design were to deliver a construction which met the load specifications of Bureau Veritas and/or Lloyds Register and provide a towing pin assembly with a calculated and proven capacity of 50 tonnes SWL, using the finite element methods. The construction and painting concept would produce pins suitable for the harsh conditions at sea.
WK has subsequently re-designed existing concepts such as the two self-closing pins (SWL 35 and 50 tonnes) with the chain/wire stopper (75 tonnes SWL) and engineered a 75 and 100 tonnes SWL towing pin assembly with a 100 and 125 tonnes SWL chain/wire stopper.
The towing pin assemblies from the ‘second generation’ are designed to be suitable for vessels with bollard pulls up to 100 tonnes, at a stroke of 400mm (50 tonnes SWL) and up to 600mm (100 tonnes SWL). The wire/chain stopper has a 75 tonnes SWL at a stroke of 400mm for the smaller assemblies and 125 tonnes at 600mm for the largest assembly.
In order to meet the regulations of Bureau Veritas and Lloyds LRS, WK calculated the applicable stress and safety factors as specified in the Rules of Bureau Veritas for Harbour Tugs (2.1), resulting in the maximum force on the towing pins and stoppers having a safety factor of two to the SWL.
Since the towing pin assembly is hydraulically operated, the system has to be connected to an existing, or stand alone, hydraulic power pack.
Recent customers for the ‘second generation’ pins include Delta Marine, Iskes Towage & Salvage, Boskalis, ST Marine, Stemat, Van Wijngaarden Marine Services and Bhagwan Marine. Damen Shipyards Hardinxveld and Neptune Shipyards modified their ship designs to WK Hydraulics asemblies and are therefore their ‘preferred supplier’ for towing pin assemblies.
