Norwegian HADEF subsidiary LM Maskin AS has supplied 100 hoists and trolleys, 12 winches and one overhead crane and other equipment to Statoil’s North Sea Kristin offshore platform.

“Once the platform begins service, there is no room for cranes, so everything needed for lifting must already be on the platform,” said Maskin technical salesman Roar Kalvsjøhagen.

The 3t overhead crane, installed in a workshop, is because it features rack-and-pinion gearing for cross travel and long travel. The rack keeps the trolley and bridge in position during high seas – though the crane cannot operate during rough weather.

The 3.2t crane uses two falls of chain to double its original 1.6t capacity. The design helps minimise headroom (820mm) by using lighter-duty (and smaller) components. The crane manages 2.4m of hook travel. It has a 5m span and 13m travel length.

Chain hoists used offshore must be lubricated daily offshore to help guard against rust. Kristin’s pneumatic hoists, some of which are stored for long periods, are picked up every three months and operated for a few seconds to keep the vane oil from hardening. The crane was installed in December 2004.

The twelve 2t-capacity winches, mounted in the platform legs, will be used for anchor chain maintenance. The winches are specced for three-phase, 690V electricity supply. “There is more and more 690V three-phase over the last few years,” he said.

Small components of the hoists need extra attention as well. All small screws, washers and nuts, all identification plates and some protection covers are made of AISI 316/A4 stainless steel.

Metal parts must all undergo special surface treatment prior to painting.