Heerema Marine Contractors is a Dutch offshore contractor with its head office at Vondellaan 47 in Leiden, where it also trades as Heerema Marine Contractors Nederland SE. The company transports, installs and removes offshore platforms and foundations, and it has moved increasingly into offshore wind work over the past decade. Its cranes and vessels are supported by in-house engineering and by fabrication yards within the wider Heerema group.
Group companies and bases
Heerema is organised into three operating companies. Heerema Marine Contractors runs the vessel fleet from Leiden. Heerema Fabrication Group builds structures at its yard at Nieuwdorp near Vlissingen, a site that has been fabricating offshore structures for more than forty years. Heerema Engineering Solutions, founded in 2019, is an engineering and consultancy business in Delft with around fifty staff, 90% of whom have offshore experience, and a record of more than 150 offshore renewable projects. Overseas offices are maintained in Houston, London and Singapore, and the group sells its services through separate contracting entities in each region.
The crane vessel fleet
The core fleet is made up of five crane and construction vessels plus two anchor handling tugs:
- Sleipnir – semi-submersible crane vessel with two revolving cranes able to lift 20,000 tonnes between them, powered by engines that can run on LNG
- Thialf – built in 1985 with class III dynamic positioning and able to perform tandem lifts of 14,200 tonnes
- Balder – deepwater construction vessel capable of a 6,300 tonne tandem lift in guyed mode, used for topsides, jackets and other structures
- Aegir – fast monohull heavy lift vessel with a 5,000 tonne crane, retractable thrusters and a shallow draft that allows quayside load-out and deck transport
- Bylgia and Kolga – two anchor handling tugs, each 72 metres long and 18 metres wide, with bollard pulls of 200 and 212 tonnes
A range of barges covers transport, jacket launch and floatover work, including the H-851, which the company describes as the largest barge in the world.
From Lake Maracaibo to the North Sea
The business began in 1948 as Constructora Heerema, a small company near Lake Maracaibo in Venezuela that built and installed drilling platforms for local oil operators. Heerema Engineering Services followed in 1962, and the group's focus shifted to the North Sea, where its first crane vessels arrived in 1963. By 1969 the ship-shaped crane vessel Challenger could lift 800 tonnes, and capacity soon rose to 3,000 tonnes. In 1978 Heerema commissioned Balder and Hermod, the first semi-submersible crane vessels, which introduced twin-crane working to the market. A joint venture with McDermott called HeereMac operated from 1989 to 1997; when it was dissolved Heerema took over the DB-102, renamed it Thialf, and founded Heerema Marine Contractors in 1997 with three of the world's five semi-submersible crane vessels. Balder was later converted into a deepwater construction vessel, the welding specialist Pipeline Technique was acquired in 2008, and Aegir was introduced in 2013.
Offshore wind and decommissioning
Heerema decided in 2018 to step back from pipelay and enter the renewables market, converting Aegir into a heavy lift vessel for wind work. Sleipnir was christened on 24 May 2019 and set a world record for the heaviest lift on 7 September of that year. The company's 2026 workload has been dominated by the Baltic Sea: working for the Equinor and Polenergia joint venture, Heerema used Thialf to install 100 monopiles, 100 transition pieces and two offshore substation jackets at the Bałtyk 2 and Bałtyk 3 wind farms over a four-month campaign, supported by about 35 vessels and managing roughly fifteen vessels at a time at peak. The company reported completion of that campaign on 2 September 2026 and expects to return to the Baltic in the winter of 2026 to install the Bałtyk 2 offshore substation, followed by the Bałtyk 3 substation in the summer of 2027. During the same period Heerema completed the final campaign of a five-year programme for Aker BP and selected Porto as the site of a new international engineering hub. Marcel de Nooijer is chief executive.
How to reach the company
General enquiries are handled through a contact form on the company website rather than a published mailbox, and the site lists full postal addresses and telephone numbers for Leiden, Vlissingen, Delft, Houston, London and Singapore. The only e-mail address published by the group belongs to its engineering subsidiary, Heerema Engineering Solutions, which gives [email protected] for its offshore wind consultancy work from Delft.