Boulder clearance

Peter Madsen Marine Contractors have been involved in ”stone fishing”, the recovery of glacial drop stones, for more than 50 years. In recent years these activities have mainly revolved around energy projects within the offshore wind and oil & gas sectors.

We offer a well proven, rapid and very cost effective boulder clearance solution using our in-house wire excavator vessels and grabs. These vessels can operate in water depths between 3 and 60 meters and have a proven track record in the offshore industry, where we have relocated thousands of boulders over the years.

We can move boulders underwater where visual identification is not required or recover to the hold if required.

In addition to ships and grabs, we provide full project management and documentation as well as a comprehensive survey package, including in-house equipment, surveyors and processing.

We can therefore handle the entire project from identification of boulders to removal and final documentation.

Key features:

  • Own ships and boulder grabs provided
  • Water depths between 3 and 60 m
  • Wire excavators can be provided with biodegradable hydraulic oil
  • No need for DP vessels, ROVs, ploughs etc
  • Positioning within +/- 20 cm
  • No need for visual identification
  • Full multibeam survey package offered
  • In-house surveyors and processing
  • Underwater video and BlueView sonar scanning
  • In-house project management and documentation
  • Cost effective and highly flexible solution
  • Tracking of “as-found” and “as-laid” positions