Monopile Loading Incident in Rostock. Photograph - Police - MV
Date 2 November 2018
An 800t monopile slipped from its slings suspended from a lifting beam and fell on to the vessel on to which it was being loaded.
The monopile came to rest on the vessel and the quayside.
The vessel, the quayside and 2 monopiles were damaged according to a spokesperson from Ørsted.
The incident happened on 31 October in Rostock, Germany, while the SAL Heavy Lift Ship, Svenja, was loading monopile foundations for the Hornsea 1 Offshore Wind Farm. The monopile was one of 174 monopiles ordered from EEW Special Pipe Constructions for Ørsted’s wind farm in the UK sector of the North Sea.
The only casualty was one crew member of the Svenja who received bruising to an arm. Following a check up the crew member returned to work on board.
At this moment there is no explanation as to how the incident occurred. While an investigation is underway the quayside is closed, and the vessel ordered to remain along side.
The force of the monopile landing on the vessel forced the Svenja away from the quayside causing all the mooring lines to part.
The 12,975t Svenja is certified as being strengthened for Heavy Cargo. It was built in 2010 and is fitted with 2 x 1,000t SWL cranes, one of which was lifting the monopile.
Comment from the Heavy Lift Specialist:
When looking at the picture above, it seems that stability of the load was insufficient. When lifting a mono pile with one single crane hook and using a lifting beam as shown in the above picture with relative short slings going from the lift beam to the hook and lifting a load from lift points below the CoG, instability of the load could occur and the load could slip out of the slings.
Loading on an earlier voyage. Photograph -SAL Press Kit
Also this lift seems to be critical on stability of the load, but they were lucky this time as it went OK
Depending on the length of slings below the hook and the friction between the slings and the load, it could be successful as shown in the above picture from a previous lift, but if the stability criteria are not met, it could slip out of the slings with the result as shown in the picture of the incident that happened in Rostock. Not many people in the lifting industry are aware of the phenomena “Stability of the Load”, when lifting a load with a single hook and lift beam or spreader.
Below is another example of an instable lift, where the crane was lifting a skid from lift points below the CoG. The hook was connected to the center lift point of the lift beam and with slings connected to lift points at the bottom of the load. It tipped until, it was stopped by the slings at one side of the load. When you want to learn more about the basic principles of lifting heavy loads safely and especially about stability of the load, join the next Seminar in Rotterdam on the 4th, 5th and 6th of Feb.2019, or subscribe to my free articles on Heavy Lifting & Transport. Check it out on: www.heavyliftspecialist.com