The majority of accidents involve personal injuries and/or fatalities, although the strong and continuous improvement in the field of accident prevention is resulting in a constant reduction of the number of marine related fatalities.
After investigating several hundred marine accidents, we are concluding that marine accidents involving equipment failure have relatively low influence in the rate of personal injury accidents.
Common accidents resulting in personal injury are caused by a condition not easy to detect by a casual observer. Hence, designers and supervisors should be alert and not to take for granted that a casual observer would recognize a dangerous situation.
The following is a description of some of the accidents investigated by the author of this article, which could have been prevented by a very inexpensive or insignificant addition of hardware.
Unsecured Hatch Cover Results in Death
An experienced Marine Surveyor was in the process of inspecting the cargo in one of the holds of a bulk carrier
He was climbing out of the hold using a vertical ladder, which terminated in an access hatch of approximately 25 x 25in. As his head reached the hatch opening at the top of the vertical ladder, he grabbed the hatch cover that was leaning in an almost vertical configuration, resting against a vertical transversal bulkhead that forms the boundary of the hold. His intention was to pull himself up to assist the passage of his body thru the hatch opening, by holding onto the hatch cover.
The hatch cover was not secured and suddenly hinged against the Marine Surveyor, pushing him down and causing him to fall. He died as a result of the fall.
The hatch related to this accident is an access hatch used frequently during loading - unloading and cleaning operations of the hold.
The hold of this vessel had four hatches, three of which had holdback hooks.
As such, these types of access hatches are normally fitted with counterbalance weights, latches, and/or various types of holdback hooks or locking dogs, to prevent the hatch cover from closing accidentally and injuring the crew.
Because the hold-back hook, latch or other securing device is normally welded to a suitable structure available in the proximity of the hatch in its open position, in most cases hold-back hooks are designed and fabricated to be used in a specific location.
Also, for locations where it is not practical to weld a hold-back hook or install a dog in the surrounding structure, hatch covers can be fitted with one or two side braces or struts that hang freely when the hatch cover is in closed position, and engage the coaming when the hatch cover is in open position, preventing the hatch cover from closing.
Of course, there are many ways that hatch opening, hatch cover, vertical ladder and surrounding areas can be improved from the point of view of safety, such as providing hand grabs, but, as a minimum, a hold back hook or latch should be part of the hatch system.
The primary cause of the accident was the lack of a device to secure the hatch in open position, such as hold down hooks, latches, locking dogs, counter balance weights or side struts. The vessels' officers and/or vessel's management should have recognized this deficiency in the vessel construction and temporary securing devices should
have been implemented, such as securing the open hatch with ropes or chains.
The master should have instructed the officers and crew regarding the need to secure any hatch that needed to be left open, if no automatic hold down devices is provided.
In summary, this accident could have been prevented by an inexpensive hold down device such as a hook.
Passenger Boarding Ramp Crushes
A passenger cruise ship carrying over 1,500 passengers made a scheduled stop at an island in the Caribbean.
Passengers disembarked using various exits, one of which is a gangway ramp that is carried aboard the vessel and is positioned by the crew between the vessel and a three step extender platform located on the dock, which was carpeted for esthetic appearance.
The ramp is designed and built to engage and to be secured to the coaming of the opening in the side plating of the hull of the vessel. Hence, the gangway ramp will be forced to move with the vessel as the vessel heaves or moves up or down as the tide changes.
Additionally, changes in the list angle of the vessel due to loading of bunkers and/or other cargo and/or wind variation will result in movements of the gangway ramp. Nevertheless, the movements are slow and smooth and are not obvious to a casual observer.
The shore side end of the gangway ramp rests in the three-step extender platform located on the dock.
To allow for the movements of the vessel, the gangway ramp is built with a 4 ½" roller at the shore side end, which allows smooth horizontal displacement of the shore side of the gangway ramp on the carpeted surface of the platform located on the dock.
The gangway ramp related to the accident being discussed did not have any type of run-off plate or other feature to "scoop" any item that could be in the path of the run-off plate and otherwise could become in contact with the roller.
On the day of the accident, a lady passenger disembarked the cruise ship, but attempted to re-board the vessel a few minutes later, while other passengers were disembarking using the gangway ramp. The lady passenger climbed the three steps of the platform and stood on the platform close to the handrail of the ramp, unaware that the ramp moves. The slow and smooth movement of the ramp was masked by the carpet and the 4 ½" roller was not visible because it was covered by the first step of the ramp.
Under these circumstances, the roller of the ramp contacted and applied pressure to the edge of the shoe of the lady passenger and, within a fraction of a second rolled over the shoe of the passenger crushing her foot.
In summary, the existence of an inexpensive run-off plate creating a smooth transition from ramp to platform would have prevented this accident.
Transmission Kills Two
There are numerous public records of self-actuated transmission accidents for both automobiles and boats. However, record-keeping practices does not identify most of the marine incidents of self-actuated transmissions.
Typically, a boat is floating free, slowly drifting with the current and wind, with the engine running but idling in neutral, as the operator prepared to remove a water skier from the water or to pick up a diver. Suddenly the gear shifted into forward or reverse without any action by the operator. If the person in the water is aft of the propeller and the gearshifts to reverse, the propeller wake (suction) will force the swimmer towards the propeller and major injuries or death will result.
We investigated two similar accidents, one resulting in two deaths and the other in injuries.
In one of the accidents investigated, two experience divers were in over 150 feet of water while the diving boat was drifting above them. We speculate that suddenly one diver developed problems with his air supply and signaled his buddy for assistance.
Both started sharing the regulators and air of one of the divers and commenced a quick ascent with their bodies in very close proximity. Probably they were busy trying to solve the air supply problem and did not pay attention to the location of the boat above them as they were descending. They hit the bottom of the boat or one of the propeller shafts, and the bump cause the gear to shift from neutral to forward. Both divers were killed instantaneously.
A typical marine gear will have a "detent spring roller" that could end up in an unstable position between neutral and forward or neutral and astern and a shock of vibration may force to shift to the closest indentation in the "detent plate".
Automobile gearboxes used to have similar problems resulting in expontaneous shifting from an apparently parking position to a gear position whenever the manual lever may or may not be in the full park position. Normally a driver assumes that he has completed the shifting task on the basis of selector "feel", while an unstable condition could easily result in the detent spring forcing the transmission into the reverse position.
The self-actuated marine gearbox was tested in a shop where after positioning the "detent spring roller" purposely between the indents of the detent plate, it was found that it would shift to gear after a number of shocks of various magnitudes were applied.
Replacement of the detent plate and detent roller improved the operation, but does not eliminate the possibility of self-actuation in the future as the detent plate and other components start wearing off.
Hector V. Pazos, P.E., is a Naval Architect, President of Ocean-Oil International Corp., a consulting group involved with accident reconstruction and providing Expert Witness services to attorneys. Mr. Pazos can be reached at (504) 367-7072 or (727) 784-8004.