Bundles and towed installation

Bundles and towed installation

13

The carrier must accommodate the flowlines and other items in a suitably spaced arrangement. It must be possible to assemble the different elements so no two flowlines are too close together, preventing the spacers from being fitted. The spacers are bolted on rather than welded (because this would cause stress raisers on the flowline). The carrier should provide around 70 mm (3 in) clearance to allow for trawl gear impact dents without the inside face touching the flowlines. The wall thickness must withstand all the stresses during towing and operation.

BUNDLECARRIERPIPE

BUNDLE CARRIER PIPE

ƒ What happens if centre of gravity is not directly below centre of buoyancy? ƒ Carrier rotates ƒ Towheads rotate ƒ Problems with laydown in the field

C of B

C of G

The centroid of the contents must be on the central axis to prevent rotation during tow. Here, we have a heavy-walled pipe shifting the centre of gravity to the right.

BALLASTCHAINS