When the Windermere Ferry’s drive wheel was unexpectedly lost mid-journey, it created an unexpected challenge: how do you locate a piece of vital equipment from the depths of England's largest lake? In such a turbid and dark environment, relying solely on divers for recovery wasn’t a safe or feasible option. That’s where we were able to lend a hand. Using sonar technology, we managed to locate the wheel and assist in its recovery, doing our part to get the ferry back on track.
The ferry operates using a chain and drive wheels which pull it across the lake.
Using StarFish to Pinpoint the Location
The first step in any underwater recovery mission is to locate the target, and for this, we relied on StarFish sidescan sonar. This compact yet highly effective tool allowed us to conduct a detailed survey of the lakebed, capturing imagery of the underwater environment. As we methodically scanned the area, we monitored the data for any objects that stood out from the surrounding terrain, eventually spotting the bright return of a large object on the software's waterfall display.
Deploying an Oculus and ROV
With the potential target located, we needed to confirm that it was indeed the missing drive wheel. To do this, we deployed an Oculus sonar integrated onto a Deep Trekker Pivot ROV, which allowed us to navigate directly to the site and capture highly detailed imagery of the environment. As we approached our suspected target, the unmistakable shape of the wheel appeared on the sonar display.
The ferry drive wheel clearly visible on Oculus M750d data
Imagery of the drive wheel captured by the Oculus M750d multibeam imaging sonar.
Once in close range, we used the ROV’s manipulator to attach a high-strength magnet to the wheel. The magnet was connected to a length of rope and a buoy on the surface, marking the exact location of the wheel on the lakebed.
Coordinated Recovery Effort
With the buoy marking the spot, the final stage of the operation involved divers descending to retrieve the drive wheel. As the visibility in the lake is essentially zero, the diver relied solely on the buoy and rope to navigate down to the wheel, where they then attached a hook and chain to retrieve the wheel. Thanks to the careful planning and preparation the drive wheel was successfully brought back to the surface, ready to be reinstated so the Windermere Ferry could get back to serving the local community and visitors.
Divers recovering drive wheel.
Technology Making a Difference
This project showcased how advanced underwater technology such as sidescan sonar, ROVs, and sonar imaging, can provide practical solutions to real-world challenges. It’s always rewarding to see how the tools we use and develop can make a tangible impact, especially so close to home here in the beautiful Lake District.