Bundles and towed installation

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Bundles and towed installation

This Orcaflex animation shows how the bundle ‘flies’ through the water column due to the effect of the drag chains. Orcaflex has a special feature which allows the modelling of bundle chains as attachments to the line (the bundle). In this model, the tow and trail heads are modelled as 3D buoys. The first animation shows the overall arrangement.

ORCAFLEXANIMATION CONTROLLEDDEPTHTOW

ORCAFLEX ANIMATION– CONTROLLED DEPTH TOW

The second animation shows a close up of the bundle as it moves off the seabed, flies along and then lies back on the seabed as the tugs slow down.

BULKHEADS

BULKHEADS

ƒ Thickness sized to:

Cold Restrained Hot

ƒ Accommodate thermal expansion seen in service

ƒ Calculate hydrostatic end forces ƒ Need to consider many cases ƒ Line 1 hot with lines 2 and 3 cold ƒ Startup from cold ƒ Ensure freedom from leakage ƒ ~300 mm (12 in) thick ƒ Usually machined from forged castings

Hot

FE stress in Britannia bulkhead

It is necessary to undertake an FEA of the bulkhead to check for regions of high stress, particularly where the flowlines pierce the plate. Here, the flowline flares out into a radiussed chamfer in the same manner as a flange.