Flotation
Offspring International offers a range of floatation methods for hawsers and chains including lace-on hawser floats, tubular floats, integral floatation and chafe chain support buoys.
SPM Hawsers typically manufactured from nylon (SG 1.14) will not float naturally in seawater. A hawser which sinks will foul the catenary moorings of a CALM buoy or other subsea equipment.
Hawser Flotation
No single flotation method suits all single point mooring environments, so Offspring International provides a range of flotation solutions designed to optimise hawser performance and service life, ensuring terminal operations run smoothly.
Lace-On Hawser Floats
Featuring a double outer layer manufactured from high abrasion resistant ballistic nylon cloth, all Lace-On Hawser Float seams are double stitched from heavy denier yarn using a locking stitch, so yarn breakages cannot lead to an unzipping effect. The floats utilise high quality 48 kg/m3 100% closed cell polyethylene foam, and high quality eyelets exceeding Shell pull test standards. Additionally, these floats can be polyurethane elastomer coated on the outside.
Integral Hawser Flotation
Integral flotation should be considered where there is a risk of conventional lace-on floats being persistently damaged or ripped away from the rope. In this case, the replacement of floats and ongoing maintenance can significantly increase the hawser’s cost-of-ownership.
Our Integral Flotation system overcomes these issues, and in addition offers many other operational benefits. Mooring hawsers incorporating the Integral Flotation system are wrapped in closed cell buoyancy foam, ensuring a minimum 20% reserve buoyancy is calculated into the construction to support the hawser in seawater.
This is covered with a machine applied overbraided jacket. Additionally, this can be polyurethane elastomer coated to enhance abrasion characteristics of the assembly.
For CALM buoys where the hawsers maybe left floating in the water between offtakes, the Integral Flotation system reduces the amount the rope will flex with the wave action. This reduces internal yarn-on-yarn abrasion damage and can help to increase retirement programmes.
Chafe Chain Support Buoys
To ensure terminal offloading remains fully operational it is imperative that the chafe chain, like the mooring hawsers, is protected from unnecessary wear and tear. Preventing abrasion and excessive movement of the chain will significantly enhance its service life. When the berth is unoccupied, each chafe chain may be supported by flotation devices.
Offspring International offers a range of chain support buoys with a typical reserve buoyancy of 900kg up to 5000kg – in addition, our flexible manufacturing process allows us to produce products to suit our customers exact buoyancy requirements.
The buoys can be supplied with swivel eyes top and bottom for connection by a short length of chain to the end link of the chafe chain, adjacent to the hawser. Alternatively, the buoys can be supplied as a chain through / locking plate arrangement chain support buoy.
For more information on Offspring International’s Floatation range email us at mail@offspringinternational.com
