200008 Overloaded for Panama Canal

Overloaded for Panama Canal
Report No. 200008

A vessel loaded a cargo of wheat in America and was bound to China via the Panama Canal. On arrival at Gatun Lake the vessel's amidships draft was in excess of the permitted maximum and she was required to discharge part of her cargo which was then reloaded after the passage through the canal had been completed.

The vessel had arrived at the loading port when required and a surveyor from the National Cargo Bureau passed the holds as being suitable for loading grain. After a slight disagreement about the stowage factor the surveyor confirmed that the vessel was within the stability criteria required by SOLAS. However, a surveyor from the Federal Grain Inspection Service rejected some of the holds due to the presence of rust scale and loose paint. The holds were cleaned and finally, after more remedial work, all passed inspection. After some differences of opinion between the master and the charterers, It was agreed that the vessel would load 42,000 metric tons of wheat. The vessel proceeded to the loading berth a few days later and the wheat was loaded in just over five hours. The practice at the terminal was to measure the grain loaded by volume using measuring equipment at the inshore end of the gantry.

The master gave the stevedores written instructions on the way in which the cargo should be loaded. On the first distribution run 14,050 metric tons were to be loaded with numbers 3 and 5 holds filled to capacity and numbers 1 and 7 holds partly filled. On the second distribution run a further 26,370 metric tons were to be loaded with numbers 2, 4 and 6 holds filled to capacity. The extra 1,580 metric tonnes would be loaded into numbers 1 and 7 holds for trimming purposes.

Loading was suspended on completion of the second run and, at this point, the master was advised that there were only 820 metric tons still to be loaded. The vessel's drafts were taken by the chief officer and this amount was then distributed in order to get the best trim possible. The draft after the second run is not known but it came to light later in the voyage that the 42,000 metric tons must have already been loaded at this point. Therefore the vessel sailed with about 800 tons more wheat than intended. The final sailing draft was 11.76M forward and 11.8M aft. However, these drafts were only taken on the inshore side and the amidships drafts were not taken at all. The draft calculations made by the master were on the basis that the vessel was floating in sea water, however, the specific gravity at the time was in fact 1015. It is fairly obvious that a vessel such as this loaded with the centre holds full and the end holds only partially filled would sag.

When the vessel arrived in the Gatun Locks she was stopped from proceeding further as it was alleged that she was over draft amidships. She was taken to Gatun Lake where a draft survey was carried out. It was ascertained that the vessel was sagged by some 15cm and also that there was 842 metric tons more cargo on board than was stated on the Bill of Lading. Approximately 600 metric tons of wheat had to be discharged into a barge to bring the draft within the limits. The excess cargo was then taken by the barge through the canal and had to be reloaded at Balboa. The whole process caused a considerable delay to the vessel.