Page 43: of Offshore Engineer Magazine (Jul/Aug 2020)

42 44

TECH TALK Bearings

Source: SKF

BIG BEARINGS BOOST

OFFSHORE PIPE LAYING s the offshore industry struggles with depressed motion of the ship on the sea). “It requires very complex en- oil pricing for nearly six years running, more gineering because of the uncertainty from the micro motions than ever it is taking a sharp eye to the bottom of the ship,” said Daniel Ortaga, Senior Business Developer line, revitalizing equipment when practical in- at SKF. The challenge for the bearings had nothing to do with stead of buying new. Recently in Norway, SKF speed, as the drums turn at around one-third of a revolution

A helped offshore equipment manufacturer National Oilwell per minute. Instead, the dif?culty was to design bearings that

Varco (NOV) achieve just that by supplying it with a unique could take enormous loads while moving at such slow rotation set of bearings … all told three different types of bearings total- speeds. As well as achieving this, SKF managed to design bear- ing more than 28 tons. ings in standard ISO dimensions, meaning they can be found

Among other things, NOV builds handling and pipe-laying within its catalogue. Strange as it may seem, these are standard equipment for offshore vessels. In a recent upgrade, it needed bearings, the largest ISO-sized bearings that SKF has ever sup- to ensure that the bearings on two cable drums could with- plied. The order comprised six separate bearings in three dif- stand the tough conditions of unspooling pipe into the sea ferent types: spherical roller bearings (SRBs); spherical roller from a pipe-laying vessel. Conditions on pipe-layers are huge- thrust bearings (SRTBs); and self-aligning CARB bearings. ly challenging, as the bearings are under constant load, both The bearings were used on two different cable drums, one radially (from the load itself) and axially (from the continuous large and one small.

JULY/AUGUST 2020 OFFSHORE ENGINEER 43