ABS Product Type Approval Deepwater Polyester Lines

NEW LEAFLET DEEPROPE

Today, two basic systems are used in deepwater mooring :

Taut-leg moorings

As water depth increases conventional, catenary systems become less and less economical. For permanent systems a cost-effective, synthetic alternative has been developed: Taut Leg Mooring.
In this system each line is strung out directly to the seabed typically at an angle of 45°. As the platform drifts horizontally with wind or current, the lines stretch and this sets up an opposing force. Our DeepRope® Polyester mooring lines have the right restoring characteristics and thus are the preferred choice for this application.
Because of the angle at which the rope arrives at the seabed the anchor will be loaded vertically. Suction piles or special anchors, so-called VLAs (Vertically Loaded Anchors) have to be used.

Insert Catenary mooring

For temporary systems either a polyester taut-leg or a catenary mooring with Dyneema® insert lines are a cost effective alternative for dynamically positioned rigs. 
The choice between these two alternatives is driven by cost of the mooring versus operational limitations.
A DeepRope® Dyneema® insert will transfer mooring forces without changing the catenary. In shallow waters, an all chains system works well but as the water depth increases the weight of the chain becomes excessive and it tends to hang directly down from the rig. By inserting a Dyneema® line the mooring stiffness increases, without a weight penalty.
Thus no modifications to the riser system are necessary when going to deeper water. Depending on the exact design it is even possible to improve the restoring characteristics. This will extend the weather window for drilling time. As the DeepRope® Dyneema® lines are neutrally buoyant they can be pre-installed with only a small surface buoy, thus reducing hook-up time.