Holdfast Training Services Trial Blog

I thought you may like the pictures. As many of you know, at the Northern Line Extension we use barges on the Thames in order to remove our muck, fed by a conveyor system from our site.

Fig 1. Empty Barge

The capacity is between 1200 and 1600t depending on which barge is being used, measured by the draught of the barge. The draught is measured prior to loading, using draught marks, and monitored during loading so that the weight in the barge is known; as a back up the weight of muck is measured as it goes over the conveyor belt.

Fig 2 Sunk Barge

So what actually happened? The Lighterman who is responsible for loading the barges was carefully watching as the barge was being loaded, the draught was ok. Despite the ever increasing reading from the conveyor belt read out, the draught was still ok. Once the conveyor belt reading was in excess of 1900t the conveyor belt was stopped, but the draught was still ok……. Turns out the barge was just sat on the river bed so despite what the photos look like, technically the barge did not sink, it just failed to float once the tide came in.