Anchor and Anchor Cable Losses. Athens, Greece, 2 nd February 2018 Capt. Simon Rapley

Transcription

1 Anchor and Anchor Cable Losses Athens, Greece, 2 nd February 2018 Capt. Simon Rapley

2 Anchor Loses Items lost: Whole anchors Anchor crowns Anchor and shackles of cable Anchor and entire anchor cable Shank Fluke Crown

3 P&I Claims Statistics In a 12 month period 12 Lost anchor cases notified to the Club Total cost: USD 250,000, many cases still ongoing, so total cost may increase 2 claims each just over USD 80,000

4 P&I Costs P&I costs that may be incurred include: Searching for anchor and / or cable Recovering anchor and / or cable from designated anchorages Fines that may be imposed by the local authorities Vessel may require an additional escort tug due to the loss of anchoring capability (especially for river passages). Tug may also be required to standby while vessel at berth Vessel may be detained while financial security for the above is arranged Cost of new anchor and cable, supply and fitting, off-hire etc. are additional costs

5 Why are Anchors / Cables Lost? Unsuitable weather conditions Whist waiting for a pilot into Rotterdam a products tanker lost 6 shackles of cable and an anchor after attempting to anchor in gale force winds. A VLCC lost the crowns off both anchors in quick succession when both anchor pins failed after the vessel repeatedly attempted to anchor in winds guesting to force 8 while waiting to berth at Ras Tanuara

6 Why are Anchors / Cables Lost? Excessive speed over the ground when anchor let go A capesize bulk carrier was proceeding along a narrow channel to a port in China when the vessel suffered a blackout due to the sea-chests becoming choked with fish. In order to prevent the vessel running aground on a nearby island the anchor was dropped at the behest of the pilot whilst the vessel was still proceeding at 7.0 knots over the ground. The anchor and the entire cable of 9 shackles were lost due to the excessive anchoring speed Excessive water depth A handymax bulk carrier was scheduled to call off a port in the United Arab Emirates in order to receive bunkers, stores and effect a crew change. The anchor and all 11 shackles of cable were lost due to the excessive depth at the chosen anchor position. The anchor and cable were eventually recovered from a water depth of 150m

7 Why are Anchors / Cables Lost? Brake banding wear down An anchor and entire anchor cable were lost when a Panamax bulk carrier attempted to anchor in the Mississippi river. The anchor had been walked back and was let go from just above the waterline into water of limited depth. As the cable paid out the crew on the forecastle were unable to check the cable using the windlass brake with the result that the entire cable paid out and detached itself from the bitter end. It was found that the brake lining on the windlass was excessively worn

8 Why are Anchors / Cables Lost? Excessive Cable Diminution (wear down) Normally anchoring whilst proceeding at 1.0 knot would be considered acceptable, however, a panamax bulk carrier lost an anchor and 5 and a half shackles of cable after dropping her starboard anchor at this speed in only 28 meters of water. In this case the anchor cable was subsequently found to be suffering from severe diminution in places and a link had failed mid-shackle as the weight came on the cable

9 Why are Anchors / Cables Lost? Joining Shackle Failure A panamax bulk carrier lost an anchor whist heaving anchor in the Mississippi river. An examination of the recovered chain end indicated that the loss was most probably due to the anchor joining shackle having not been properly secured to the anchor Dropping an anchor on a rocky seabed Crowns and flukes can be damaged when dropped or fouled on rocks

10 Actions if Anchor / Cable is Lost Obtain an accurate position where the anchor / cable were lost, consider the relative position of the hawse pipe in relation to the location from which the position was obtained radar scanner, GPS antenna etc. Record the direction in which the cable was laying Record the weight and type of anchor, and its serial number Record the bar diameter, length and weight of the anchor cable Advise your owners, local authorities, P&I Club / P&I Club Correspondent, Classification Society and H & M Insurer. A report may be required to the Coast Guard / local authorities

11 Design of Anchoring Equipment IACS requirements state: The equipment is therefore not designed to hold a ship off fully exposed coasts in rough weather or to stop a ship which is moving or drifting. In this condition the loads on the anchoring equipment increase to such a degree that its components may be damaged or lost owing to the high energy forces generated, particularly in large ships

12 Design of Anchoring Equipment Anchoring equipment assigned to a vessel based on Class Rules, using a formula which considers displacement, breadth, summer freeboard, superstructure and hull profile areas Assumed maximum 5 knot current and 50 knot wind, no waves Alternatively for a vessel over 135m LBP, can be considered applicable to a maximum 3 knot current, maximum 22 knot wind and maximum 2m significant wave height Designed to hold the vessel in good holding ground Assumes a generous scope of cable out: 6 to 10 x depth of water Assumes one bow anchor and cable in use at a time

13 Anchoring Best Practice Rotate the use of the anchors to spread the wear Ideally walk the anchor back clear of the hawse pipe prior to letting go Do not drop anchors at an excessive speed over the ground Do not attempt to anchor in excessive water depths REMEMBER windlasses are usually designed to hoist the anchor and 3 shackles only (82.5m of cable) remember to consider any working length of cable between the anchor and the first shackle!

14 Anchoring Best Practice Do not let go heavy anchors, walk it back all the way, and keep astern speed below the speed of the windlass, typically <0.3 knot In deeper water and on rocky seabeds, walk back the anchor to just above the seabed prior to letting go Keep the bridge informed of the number of shackles out, anchor cable direction and weight / length of stay When the anchor is brought up, put the chain stopper on and disengage the clutch

15 Anchoring Best Practice Do not try and anchor in unfavourable weather conditions Do not remain at anchor when conditions deteriorate such that it is difficult to recover the anchor. Vessels have dragged anchor over submarine pipelines, cables, drifted into fish farms and also grounded

16 Anchoring Best Practice Windlass motors have catastrophically failed when attempting to heave an anchor in heavy weather and personnel have been injured Avoid excessive weight / long stays when heaving anchor, use the engine and rudder to ease the recovery of the cable. Anchor party regularly report number of shackles out, anchor cable direction and weight / length of stay

17 Securing Anchors for Sea The anchors must be secured for the sea passage to prevent movement of the anchors in the hawse pipes, anchor shackle pins can become loose Heave anchor tight, tighten windlass brake and disengage clutch

18 Securing Anchors for Sea Chain stoppers / guillotine bars, designed for 80% of the breaking strength of the anchor chain Ensure securing pin (stainless steel drop nose pin) in place

19 Securing Anchors for Sea Wire lashings should be fitted and tightened Turnbuckle locking nuts, if fitted, must be applied

20 Anchoring Equipment Planned Maintenance Planned Maintenance System (PMS) must cover: Inspection of the anchor, anchor shackle, enlarged links, swivel and joining shackles (Kenter / Baldt / Lugless) for damage, weardown and missing items

21 Anchoring Equipment Planned Maintenance Planned Maintenance System (PMS) must cover: Inspection of the cable for damage, weardown and loose studs. IACS Class Societies required anchor cable replacement when weardown exceeds 12% diameter

22 Anchoring Equipment Planned Maintenance Planned Maintenance System (PMS) must cover: Inspection of cable markings, both permanent and painted Brake band thickness and condition of mating surface, brake functionality periodically test brake holding capacity Hoist motors to be maintained in accordance with manufacturer s recommendations Inspection of bitter end and availability of tools for quick release Gypsy for weardown Ranging of cables for inspection at routine drydockings in line with Class requirements Walking the anchor working shackle by anchor removed and refitted at the bitter end during drydockings

23 Anchoring Equipment Planned Maintenance Check weardown of guillotine bar, hinge and securing pin Ensure shackle pins are moused in place If the devils claw is damaged, replace, do not repair by welding Renew wire lashings periodically when damaged / corroded Renew associated shackles etc. when damaged / corroded

24 Conclusions Remember the reasons that anchors and cables are lost: Anchoring at an excessive speed over the ground Anchoring in deep water Unsuitable weather conditions remember the IACS design criteria Letting go heavy anchors, rather than walking them back Letting go anchors over a rocky seabed Worn brake banding / poor condition of mating surface on windlass Lack of brake control Clutch slipping out securing pin on control arm not in place Joining shackle failure Swivel failure excessive weardown Anchor shackle failure Excessive cable diminution / loose studs

25 Thank You