I had two good experiences with passive flume stability tanks. One was an oceanographic research vessel which spent much of its time at sea drifting at sea and the other a small general cargo vessel. It was back in the days of pencil and paper and the calculations took an appreciable time on the cargo vessel . Once the tank level required was obtained the effect was so dramatic that there was complete cooperation from all hands. The bosun sounded the tank and signaled the bridge from the mast house (no radio then). The emergency telegraph rung and the duty engineer stopped the pump.
I did some arithmetics on the accelerations which will occur at bridge level with a roll of 44° in 10 seconds. The results are I think a bit mind blowing but please correct me if I am wrong. The second mate who was able to hold on to the chart table, probably by grabbing the handrail, must have been a stout fellow because if he weighed 75 kg with that acceleration his weight would have increased to 148 kg.
The lateral forces on the containers is another matter and is depending on the weight of each container, the x, y, z coordinates with reference to the LCF and the acceleration at that position. That was an excellent lashing job what they did on this ship!
The swing along the arc at 40 m bridge height is 61.4 m. With the roll time of 10 seconds this amounts to a speed of 22.1 km/u.
I cannot make such a graph for the MSC Zoe because insufficient data is available such as the GM. For instance, with that value the roll time could be calculated. With the USCG Weather Criterion I calculated earlier a GM of 1 which is pretty low for a container ship. For the Chicago Express I calculated with the Criterion a GM of 6. The ship sailed from Hong Kong with a GM of 7.72.
IMHO she was rolling heavily and touching bottom on her starboard side causing massive decelerations that overcame the lashing. The forces generated were in excess of the design parameters.
I would like to see a side scan of the seabed along her track, no doubt it will come out in the report.
I wrote this before and as you said it is a serious possibility. Hitting the sea bottom will produce a jolt or jerk which is the rate of change of the acceleration with a short duration with a magnitude of m/s³. This can also be expressed in standard gravity per second (g/s).
I calculated the acceleration at bridge level that is caused by such a jolt as > 5 g! Anything can potentially break then…
This picture shows the different allowable values for the g forces during a rollercoaster ride.
Screenshot taken today at 13:40 GMT
The small round symbols are stationary objects such as stopped ships.
One can wonder why not more serious incidents have happened on these overcrowded routes which are also lying so close to a protected heritage area of which the polluted islands are part of. Until now 51 containers are still missing.
Also fishers are helping with the cleaning operation.
News reports yesterday in the UK of hundreds of dead birds being washed up on the shore near where the containers were lost.
The loss is far greater than thought:
The recovery operation is costly with a large fleet of vessels engaged to locate and salvage the containers and spilled cargo from the seabed:
Who knows which stow-software the MSC Zoe used prior to it recently losing containers?
So far very little information about the accident has become available to the public which leaves room for a lot of speculation. Some of the most commonly used software for ships planning are CASP, MACS3 and Bulko, could be any of these. Is there a specific reason that you want to know the stowage software used on the MSC Zoe?
2 posts were split to a new topic: Two utes valued at $300k among treasures lost in container spill