Damage to ship's propeller - Univan

File No CR-15-009 Prep: SJ/NH Rev: SH
Case Name Damage to ship’s propeller
Device Name NA
Maker Name NA Model NA Working Hrs. /
Built
NA
Kind of Ship Bulk Date 18-02-2012 Place NOLA
Cause of
incidents
Carrier
Error of judgment during unberthing maneuver in Mississippi River
leading to damage to ship’s propeller and buoy
Synopsis of the Incident
A bulk carrier arrived NOLA and was secured at Cooper Consolidated Mile 133 multi buoy
moorings on 10 th Feb 2012 for discharging a full cargo of DAP.
The vessel mooring arrangement consisted of riding her both anchors and ropes leading forward to a
set two of buoys on port & starboard bow and ropes leading to a set two buoys on port & starboard
quarter. The mooring arrangement had vessel facing upstream into the river current on a heading of
295 (T) lying within the 4 buoy moorings equally spaced.
INITIAL MOORING PATTERN AT MULTIBUOY MOORING
Normal Mooring when all fast
Both anchors
Fwd mooring buoys
Aft mooring buoys
Page 1 of 5

On completion of discharging operations on 17 th night, the vessel prepared for sailing on 18 th Feb
early morning. However in the final stage of unmooring on 18 th early morning, it was noticed that a
wire rope was entangled in the starboard anchor. As it was not possible to disentangle the wire by
manual means and required shore assistance. It was decided to re-moor the vessel.
Port Anchor
3 Shackles
on deck.
Current
E x 2.9 Kts
RE-MOORING PATTERN
Fwd mooring buoys
Modified temporary mooring arrangement while
clearing fouled anchor.
Aft mooring buoys
This re-mooring consisted of ropes leading to set of two buoys on starboard bow. Another set of two
ropes was passed to two buoys on starboard quarter. The port anchor was heaved up to 3 shackles so
as to pull the vessel’s bow out of multi buoy mooring (4 buoys) towards the port side. The starboard
anchor was hanging with the fouled wire rope. The ships heading on completion of re-mooring was
290 (T).
Page 2 of 5

Later on 18 th Feb morning the starboard anchor was cleared and vessel was prepared to unmoor and
sail outwards. Main Engines were tried out and order for SBE given at 0936 hours.
Prior Unmooring two tugs “Mississippi (60 T Bollard Pull)” and “Providence (40 T Bollard pull)”
were made fast on port bow and port quarter respectively. Vessel let go and pick up her stern ropes
which were both leading on starboard quarter. On letting go the stern ropes the ships heading was
observed to be 260 (T) as the ships had swing to port slightly.
After this the head lines which were leading to starboard bow were let go and picked up.
After this vessel proceeded to pick up her port anchor. As per ships deck log book port anchor was
aweigh at 1012 hours LT.
Following are the ME movements given and recorded in telegraph logger)
TIMING HOURS MINS SEC ORDER/ACKNOWLEDGED BY ME
(UTC=SMT+6)
16.11.41 D S AHD
16.14.52 S AHD
16.15.18 H.AHD
16.15.43 F.AHD
16.16.32 0 RPM (RPM has dropped from 55 RPM to Zero)
Thereafter, Master put his Engine Order telegraph to “Stop” realizing that ME RPM has either
dropped to Zero due to hitting some obstruction or ME is not responding. Master then took up the
ME RPM in stages to Full Ahead.
At 1030 hours LT Cooper Consolidated reported to the vessel that a port aft midstream buoy was
adrift as its chain had apparently been struck by the ships propeller whilst carrying out unberthing
maneuver. As per Cooper Consolidated the Pilot acknowledged the contact with buoy.
Following facts need to be borne in mind-
Sailing draft- F-4.00/A-6.45 meters.
Propeller Immersion- About 5.70 meters.
Diameter of the propeller- 5.45 meters.
Propeller shaft diameter-900 mm.
Weight of the propeller- 11 MT.
Rated torque of propleller-14 MT.
Cause Analysis:
On re-mooring the ship was lying outside the 4 buoy mooring pattern. Both head ropes were leading
to starboard bow and both stern ropes were leading to starboard quarter. The weight was on port
anchor which had 3 shackles in water. Therefore though the ropes leading aft were showing a paid
out length of 70 & 40 Starboard and port aft rope respectively) meters the actual horizontal clearance
of ship from buoys was much less as the lead of ropes was at an obtuse angle as ship was not
squarely placed within the buoy pattern.
At this position ships heading was 290 (T) as per ship’s records.
Once the stern lines followed by head lines were let go the ship turned to port to face the stream and
ride the port anchor. This turn to port and tightening of the port chain brought the ships stern closer
to port aft buoy. The ship’s log shows port anchor aweigh time as 1012 LT (1612 UTC).
Page 3 of 5

The Engine Order Recorder shows that from 16.11.41 UTC (10.11.41 LT) to 16.15.43 UTC
(10.15.43 LT) –that is within 3 minutes and 2 seconds, ME orders being ramped up from Stop to
Full ahead showing the urgency with which pilot reacted to the situation.
As soon as anchor was weighed, the vessel needed to overcome the force of river stream and then
move ahead to clear the buoys abaft. The strength of the stream in this location was 2.9 Kts, this will
make the vessel fall back by 1.45 cables in 3 minutes.
The forward tug was used by the pilot to pull at 45 deg angle to prevent the vessel from falling back.
However, the aft tug was kept only stand by.
The sudden drop of RPM at 16.16.32 UTC (10.16.32 LT) is the time of impact of propeller with
buoy chain and corresponds to position of ship after picking up anchor. As per calculations based on
the point from which the chain has been cut and vessels draft with relation to angle of chain at 2.9
Kts current it is calculated that the bouy was 2 M from the stern when the propeller hit the chain.
Fwd Tug
Port Anchor
3 Shackles
on deck.
Current
E x 2.9 Kts
Aft Tug
Fwd mooring buoys
Position of vessel upon cast off
Aft mooring buoys
Page 4 of 5

ROOT CAUSE OF THE ACCIDENT
1. Failure to report the propeller clearance from the aft station.
2. Failure to effectively utilize the aft tug.
3. Failure to appreciate the strength of river current and failure to give robust ME movements during
picking up anchor and immediately thereafter.
LESSONS LEARNED / PROPOSED COUNTER MEASURES
1) Pilot actions to be monitored and challenged if necessary.
2) Handling ships in open waters is very different from handling ships in river/near berth. The
catenary of the buoy chain can be different from direct leads.
3) No claims can be enforced for pilot error unless willful negligence can be proved. Master is
to exercise his authority for safety of the vessel.
4) Continuous monitoring of all obstructions to be done and reported to wheelhouse till vessel is
clear.
Corrective Action
1. Ship under water inspection arranged at next port of call, Tampa.
2. Repair of propeller as per Class recommendations.
3. Damage to buoy and loss of buoy cable and anchor case referred to P&I, claims expected in
range of USD 230,000/.
Preventive Measures
1. Advanced ship handling training for Master to be arranged.
2. All vessels to discuss this incident in next safety meeting and highlight the importance of
clear communication during mooring stations.
Gouge on Leading Edge of Blade A Near Tip
Page 5 of 5