Offshore platforms can weigh thousands of tonnes, and placing their modules at sea is a remarkable engineering challenge. Heavy-lift vessels and floating cranes are designed to move these loads in a controlled way.
1. The crane is mounted on a specialised vessel
A floating crane is supported by a ship or barge designed to carry large loads. The vessel’s shape, stability and ballast system help it remain within safe operating limits as the crane works.
2. Engineers plan the lift in advance
Teams calculate the load’s weight, centre of gravity, lifting points, sling forces, sea conditions and the crane’s capacity at the required reach. A lift plan includes limits for wind, waves and vessel movement.
3. Ballast helps manage stability
Some vessels move water between ballast tanks to adjust trim and stability. Ballast is only one part of the system; hull design, load placement and operating limits all matter.
4. The load is moved slowly and monitored
Sensors and operators monitor loads, position and vessel movement. The lift is coordinated so the structure is raised, transferred and lowered without sudden movements that could overstress the crane or the load.
Why are these lifts so difficult?
At sea, waves and wind add movement to an already complex operation. The safest lift is not simply about having a powerful crane—it depends on calculations, equipment, weather windows and experienced teams.
Key takeaway: giant floating cranes combine heavy-lift machinery, stable vessels and detailed engineering plans to move enormous structures safely.