Synthetic ropes
Recommended practise for handling fibre rope mooring lines before and during installation.
•Ropes should not be permanently installed around bollards or fairleads.
•A minimum bending radius should be observed. The minimum bend radius (D/d) with very low line tensions should be larger than 6.
•When unreeling the rope, maximum line tension should be observed, to avoid pulling the rope into the underlying layer.
•Torque or twist in the rope should be avoided.
•Fibre ropes should not be run over surfaces which have sharp edges, grooves, nicks or other abrasive features.
•Care should be taken when applying shearing forces to the rope.
•There should be no “hot work” such as welding in
the vicinity of the rope. |
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•Frictional heat from excessive slippage of the fibre rope over a capstan, drum, etc. must be avoided.
•Care should be taken that ropes do not get knotted or tangled.
•Rope contact with sharp gritty materials should be avoided.
•Abrasion or fouling of the mooring line with other anchoring equipment such as anchor, steel wire rope, chain and connectors must be avoided.
•Chasers should not be used on fibre ropes.
•Shark jaw stoppers designed for use with steel wire rope or chain should not be used for handling fibre ropes.
•It should be avoided that the ropes undergo more than 1000 loadcycles with a line tension smaller than 5% of the MBL.
•Pre-deployed lines should not be left buoyed at the surface waiting connection to the platform, unless a minimum line tension of 5% (for polyester) of the MBL is maintained.
•If the fibre rope is laid on the seabed, it must be protected against external abrasion and ingress of abrasive particles.
Mooring hawsers
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Double braided nylon |
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Circular braided nylon |
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Deltaflex 2000 |
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Circ. |
Diameter |
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Ndbs |
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Nwbs |
weight |
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Ndbs |
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Nwbs |
weight |
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Ndbs = |
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weight |
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inch |
mm |
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t |
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t |
kg/m |
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t |
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t |
kg/m |
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nwbs t |
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kg/m |
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12 |
96 |
208 |
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198 |
5.7 |
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205 |
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195 |
5.0 |
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217 |
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5.7 |
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13 |
104 |
249 |
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236 |
6.7 |
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256 |
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244 |
6.0 |
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258 |
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6.7 |
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14 |
112 |
288 |
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273 |
7.8 |
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307 |
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292 |
7.3 |
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297 |
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7.8 |
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15 |
120 |
327 |
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311 |
8.9 |
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358 |
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341 |
8.4 |
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339 |
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8.9 |
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16 |
128 |
368 |
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349 |
10.2 |
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406 |
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387 |
9.5 |
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378 |
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10.2 |
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17 |
136 |
419 |
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398 |
11.4 |
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454 |
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433 |
10.7 |
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423 |
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11.5 |
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18 |
144 |
470 |
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446 |
12.8 |
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501 |
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477 |
12.0 |
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468 |
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12.8 |
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19 |
152 |
521 |
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495 |
14.3 |
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547 |
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521 |
13.2 |
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523 |
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14.3 |
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20 |
160 |
577 |
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548 |
15.8 |
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597 |
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569 |
14.4 |
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578 |
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15.9 |
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21 |
168 |
635 |
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603 |
17.4 |
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644 |
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614 |
15.7 |
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636 |
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16.9 |
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Specific gravity |
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1.14 |
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1.14 |
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1.14 |
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Melting point |
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250˚C |
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215˚C |
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260˚C |
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Note : ndbs |
= new dry break strength in spliced condition |
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nwbs |
= new wet break strength in spliced condition |
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Deltaflex 2000 in 8 strand plaited construction. |
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Approximate elongation at |
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Circular braided nylon (double braided |
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Deltaflex 2000 |
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first loading (broken- |
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is similar) |
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in rope, dry and wet |
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condition) |
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At 20% of MBL |
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± 16% |
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± 19% |
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At 50% of MBL |
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± 22% |
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± 26% |
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At break |
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± >40% |
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± 33% |
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Mooring hawsers
Double braided construction versus circular braided construction
The circular braided construction can be defined as a recent alternative for the double braided construction. The elongation and TCLL values of both construction types are the same. The efficiency (breaking load/raw material) of the circular braided construction is however much higher, which means that the circular braided construction can be more budgetary attractive.
Both construction types have an overbraided jacket as part of their construction, but the important difference is that where the overbraiding of the double braided construction is load bearing, the overbraiding of the circular braided construction is just there for protection. This means that when the overbrai-
ding is damaged due to chafing or other reasons, the 127 stability and break load of the circular braided con-
struction will remain unchanged, while the double braided construction should be considered as structurally damaged (loss of stability and a lower break load).
Advantages of Deltaflex 2000
When compared to nylon hawsers, a Deltaflex 2000 hawser has the folowing advantages:
•Equal strength in dry and wet conditions.
•Strength is 10% to 20% higher than wet double braided nylon.
•High energy absorption and elastic recovery.
•No water absorption.
•One of the highest TCLL (thousand cycle load level) values of all sysnthetic ropes.