At Rotterdam’s Calandkanaal, Heerema Marine Contractors is carrying out a wide-reaching life-extension program on its semi-submersible crane vessel Thialf, described as one of the most comprehensive renewal efforts in the ship’s history.
The current scope covers structural steel renewal, electrical modernization, safety-system replacement, and accommodation upgrades. Work is progressing alongside the quay, while a dedicated drydock period after the offshore season is scheduled to finish further tasks and complete exterior refurbishment.
A key focus is structural longevity. Hull steel is being replaced and renewed to extend service life. On the electrical side, the main switchboards are being replaced to meet today’s operational and safety requirements.
Support and safety systems are also being refreshed. Sewage and firefighting systems are under renewal, and the accommodation package includes updates to living areas and the onboard hospital. These upgrades may be less visible than lifting capability, but they underpin compliance, crew welfare, and day-to-day reliability.
Attention is also directed at mission-critical equipment. Thrusters, cranes, and dynamic positioning systems are being prepared for long-term service. For offshore wind foundations, topsides, and decommissioning lifts, DP performance and crane reliability are central to execution. A single failure can disrupt installation sequences and impact wider supply chains.
The timing reflects a phased plan to protect commercial availability. While the Rotterdam work continues, Thialf is preparing for a busy summer offshore campaign, with mobilization expected next month. In offshore installation, downtime can reach hundreds of thousands of dollars per day, making technical risk reduction and uptime a strategic priority.
With new ultra-large crane vessels requiring major capital and long lead times, life-extension programs are increasingly positioned as a practical route to keep proven heavy-lift capacity available as project schedules tighten.
