API RP 2I:2008 pdf download
API RP 2I:2008 pdf download.In-service Inspection of Mooring Hardware for Floating Structures.
Excessive corrosion increases the possibility of chain failure from fatigue o overloading due to reduced cross-
sectional area,
2.1.4 Sharp Gouges
Physical damage to the chain surface (such as cuts and gouges) raises stress and promotes fatigue failure.
2.1.5 Loose Studs
Loose studs caused by manufacturing defects, abusive handling, or excessive corrosion between the ink and the stud, allowing excessive stretching of chain, causing higher bending stresses in the chain. A typical loose stud is shown in Figure Ia.
2.1.6 Cracks
Surface cracks, (lash-weld cracks, and s*u&weld cracks may propagate under cydic loading, resulting in premature chain failure. A typical stud-weld crack is shown in Figure lb.
2.1.7 Wear
Wear between links in the grip area and between links and the wildcat (see Figure 2b) reduces the chain diameter.
The diameter reduction decreases the load-carrying capacity of the chain and invites failure.
2.1.8 Elongation
Excessive permanent elongation may cause the chain to function improperly in the wildcat, resulting in bending and wear of the links. Wear in the grip area of the chain and working loads in excess of the original proof load wil result in a permanent elongation of the chain.
2.2 Recommended Inspection Method
2.2.1 General
Chain installed on MODUs can be inspected by the two methods discussed in 2.2.2 and 2.2.3.
2.2.2 Dockside Inspection
As shown In Figure 3, the drilling vessel is taken into a dock, and the chain Is laid out for inspection. Normally such chain inspection is carried out in conjunction with other work such as major structural repair or special survey.
In this manner the entire chain can be thoroughly cleaned and carefully inspected, and the connecting links and anchor shackies can be examined by magnetic particle inspection (MPI). Since the chain is not under tension, the chain diameter in the grip area can be readily measured. However, the measurement of a length of five links, in this case, wtiách should be accomplished under tension, would be inaccurate.
2,2.3 Offshore InspectIon
As shown in Figure 4. the drilling vessel stays offshore, and the chain is inspected with the assistance of a workboat. The chain in the chain locker should be paid out fully and then examined by an inspector standing close to the windlass while the chain is slowly taken back into the chain locker. At the same tme. the worlcboat picks up the anchor and moves slowly toward the vessel.
2.3.1.2 Offshore Inspection Method
The following list describes personnel and duties for the offshore inspection methods:
a) the windlass operator runs and slops chain on the order of the chief inspector, stopping chain after every 100 ft of chain movement;
b) the chief inspector coordinates the work among the nspection personnel. gives orders to the windlass operator, rejects am accepts damaged links, and performs visual inspection and measurements:
C) the assistant inspector keeps inspection records, performs visual inspection, and assists with measurements;
d) the MPI inspector performs MPI on anchor jewelry and spare connecting links prior to inspection;
e) roughnecks clean chain, grind out surface detects, change connecting links, and assist with inspection of anchor jewelry.
2.3.2 Equipment
The following equipment is often needed for chain inspection. Its need and availability should be checked before the inspection is started:
a) wcxkboat (offshore inspection method);
b) dockside crane or other suitable equipment to lay out chain (dockside inspection method);
c) high-pressure hose:
d) sandblaslrng equipment;
e) MPI equipment;
f) go-no-go gauge for chain diameter measurement (see Figure 2e);
g) go-no-go gauge for maximum allowable length over five links (see ‘Offshore Inspection Method. in F-igure 5iq u, go-no-go gauge for maximum allowable length of individual link (see ‘Dockside Inspection Method, Figure 5b);
h) steel wire brush;
I) hammer;
j) spare connecting links that have been inspected by MPI (a sufficient number of connecting links must be prepared for replacing existing connecting links and damaged common links);
k) winder;
I) diameter caliper (see Figure 2d);
m)measurlng tape;
n) tape recorder;
o) spray paint;
p) camera;
q) lighting equpnent.