Construction – Offshore Foundations

Fabrication begins on sections of the steel monopiles, at the Smulders facility in Hoboken.

The first monopiles awaiting transport to site and installation.

First full foundation to be installed at Triton Knoll from the Seaway Strashnov on 17 January 2020.

Overview

The design of the monopile foundations was carried out by UK engineering firm Atkins on behalf of Triton Knoll's lead contractor 3SF (a Smulders Sif Joint Venture). The design work represents an important progression within the offshore industry in the fabrication of lighter and more cost effective infrastructure; the modern design has saved the equivalent of over 3 Eiffel Towers worth of steel in the manufacturing process, while preserving the strength of the asset.

The transition pieces are the bright yellow sections that sit on top of the monopiles. The turbine towers, nacelles and blades are built on top of the transition pieces.

Installation of the foundations is being carried out by a specialist vessel called ‘Seaway Strashnov’, and which is operated by Seaway7. It first arrived on site in January 2020. The vessel is 183 metres in length and is capable of lifting up to 5,000 tonnes.

Principal Contractor: 3SF (design and supply); Seaway7 (transport and installation)

Expected completion: Q3 2020.

Progress Updates

The first full foundation was safely and successfully installed at Triton Knoll, by the Seaway 7's Seaway Strashnov on 17 January 2020.

On 17 January, 2020, Triton Knoll safely and successfully installed the first of its 90 wind turbine monopile foundations, 32km off the Lincolnshire coast.

The c.600 tonne steel monopile and its bright yellow transition piece was installed by Seaway 7's (1) ‘Seaway Strashnov’ which is contracted to transport and install all 90 of the wind turbine foundations, as well as the two offshore substation platforms and their foundations.

The 'Strashnov' leads a fleet of vessels including the the high-tech Service Operation Vessel (SOV) ‘Esvagt Froude’ (2) operating out of Grimsby’s Royal Dock, in support of  the construction of the wind farm.

The ‘Seaway Strashnov’ arrived on site at the beginning of January to install the turbine foundations, subject to weather conditions. The vessel is 183 metres in length and can lift up to 5,000 tonnes.

Each steel monopile weighs on average 600 tonnes and is around 54 metres long - longer and similar in width to the cabin of an Airbus A380 (3). The foundations design, by UK engineering firm Atkins on behalf of lead contractor 3SF (a Smulders Sif Joint Venture), represents an important innovation and has saved the equivalent of over 3 Eiffel Towers worth of steel in the manufacturing process, while preserving the strength of the asset.

 

(1) Seaway 7 is Subsea 7’s Renewables and Heavy Lifting business unit.

(2) Service Operation Vessels (SOV) are specially designed to support a continuous presence offshore, enabling crews to live for up to four weeks at a time in the field. The vessels improve efficiency and safety by reducing the need to travel from shore each day. The vessels have fully-fitted accommodation units and include a range of facilities to support onboard living.

(3) Airbus A380 dimensions - http://www.modernairliners.com/airbus-a380/airbus-a380-specs/