Mijke Lievens, Fallpipe vessel operations
“If equipment needs to be modified for a project I am the link between the different departments and the vessel. We think about every change with a lot of people, but still you miss details; it never completely fits the way you planned it.
Take the modification of the Rockpiper for the Veja Mate project. Prior to the installation of the monopiles we had to install a filter layer of small rock, followed directly by an armor layer of large rock. The problem, however, was that the rock required did not fit through the fallpipe. We came up with the solution to use a string of bottomless buckets. We could pile them up above the moon pool and, after installing the fine rock, attach them via a suspension piece to the upper part of the fallpipe.
When we tested this in the sheltered surroundings of the Norwegian fjords it turned out we could not clench the fallpipe wires with the regular equipment (gallows) to the smaller diameter of the fallpipe. How far do you then go to make it work? A bit too far sometimes, I think. At a certain moment a man climbed onto the top of the pipe, of course with required PPE and fall protection, but still not as planned and described. In practice, however, we all do our utmost to make it work. That is the atmosphere on board, and it is great, but it reveals a huge dilemma: when do you conclude ‘this is not acceptable’? Luckily we decided in time to stop the work and find another solution. We chose to switch between the loads: first install the filter layer, then go back and attach the buckets to the pipe during the loading operation of the large rock. At that moment there is no tension on the wires and it can be done safely. Should we have made this decision earlier? Maybe, but you also want to investigate the possibilities. Most important lesson is: stop the work when necessary. That is the only way to safely test new equipment or work methods.”