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We’ve built 1,700 turbines of experience into Sea Installer

A2Sea’s second-generation wind turbine installation vessel, Sea Installer, is the result of more than a decade of practical experience in the field of offshore wind turbine and foundation installation. It has been designed to operate in the more challenging conditions that encountered further offshore and in deeper water. A purpose-built vessel, the Sea Installer is designed to transport and install up to eight 4MW turbines or four 8.3MW turbines. And, with a reinforced deck as long as a football pitch, she’s made to carry large, heavy loads.

Forward thinking

This vessel is the ideal solution for the next generation of European offshore wind farms. Sea Installer’s crane placement and free deck plan are ideally suited to turbine transport and installation. And it is capable of direct feed from component production facilities, eliminating the inefficiency of trans-shipment at local logistics harbours.

Four beats six

With her four legs, the Sea Installer has less payload than a six-legged vessel, but a more feasible distribution over the entire deck area. The middle legs of six-legged vessels often get in the way, which can be a major problem when planning lifting operations. The four-leg configuration provides much better clearance and manoeuvrability for the vessel’s cranes. Instant manoeuvrability, a deck built to withstand massive loads, a crane that can slew 360 degrees, extend 100 metres and lift 900 tonnes, and a long list of other advantages make Sea Installer a solution that’s hard to beat.

More than meets the eye

There’s more to Sea Installer than meets the eye, however. For example, careful placement integrates the vessel’s plentiful accommodation without affecting the vessel’s primary purpose. And electric cranes minimise noise to protect both the external environment and ensure the best working conditions. Extra generators boost production uptime, providing fault tolerance to ensure 24/7 use of the vessel.

Sea Installer can operate in water that’s 60m deep or more, load up to nine turbines at a time and carry out installations in a wider array of weather conditions.

Not only can Sea Installer be able to carry more turbines at a time, she can also sail quickly back to harbour and reload – an essential capability when wind farms are located so far out at sea.

The vessel includes two features that will make operations safer and more efficient. The first is Dynamic Positioning (DP2), which uses GPS navigation and laser to keep the vessel in position during installation. The second innovation is the position of the crane. Instead of standing in the middle of the deck, it is wrapped around one of the vessel’s four jack-up legs, providing less obstruction. And, positioned close to the edge of the vessel, the crane has a much greater reach.

Instant reaction

Equipped with a DP2-class type dynamic positioning system and a Voith Schneider propulsion system, the Sea Installer can change direction in an instant. Much faster than conventional systems with one shaft and a rudder, the Sea Installer’s Voith Schneider propellers and propulsion system make the vessel very stable and manoeuvrable, even under extreme conditions with high currents and wind speeds. Thanks to improved stability and better use of deck space, Sea Installer can carry out installations even in harsh winter weather.

Sea Installer takes the installation process to a more efficient and cost-effective level, giving developers greater confidence that their projects will be delivered on time and with maximum profitability.

Download brochure Sea Installer – Technical specification and Track Record


Technical Specifications

Vessel: Sea Installer
Type of vessel: DP2, Self-propelled jack-up vessel
Classification: DNV GL
Flag: Danish

Technical dimensions
Length: 132.41 m
Breadth: 39 m
Draft: 5.8 m
Leg length: 82.5 m
Deck load: 15 t/m²
Free deck space: 3,350 m² (subject to deck layout)
Total net deck load: Approx. 7,400 t available for cargo/seafastning/ballasting for stability

Service speed 12 kn max
Operating water depth: 6.5–55 m (depending on tide, penetration)

Jack-leg System
No. of legs: 4
Jacking system: Double hydraulic
Jacking speed: 0.40 m/min
Spudcan footprint: 106 m²
Wave limit jacking: 1.8 m Hs (subject to site-specific assessment)
Elevated weight: 20,500 t

Main Crane
Type: Gusto GLC-900-ED-S
Crane capacity:
95 m boom length, 900 t @ 24 m outreach (623 t @ 30 m)
115 m boom length, 700 t @ 28 m outreach (632 t @ 30 m)

Cargo Crane
Type: Marine cranes
No. of cranes: 5
Crane capacity:
2 no. 3.4 t @ 25 m max 20 t
2 no. 2.5 t @ 25 max 10 t
1 no. 4 t @ 33 m max 30 t

Tank Capacity
Fuel: 1,000 m³
Fresh water: 550 m³
Sewage tanks: 400 m³

Power Sources
Main engines: 6 x 3020 kW
Power supply: 6.6 kV, 400V, 230V, 110V, 50 Hz

Charterers’ Accommodation
Charterers’ personnel: 35 persons
Charterers’ cabins: 35 single cabins
Office facility: 2 offices with 6 desks
Other facilities: Rest lounge (shared with vessel crew)
Mess room (shared with vessel crew)
Gym facilities (shared with vessel crew)

D-value: 22.2 m
T-value: 12.8 t
Can be used both floating and jacked up



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