VESSEL REVIEW | Pole Star – UK's Northern Lighthouse Board acquires large hybrid buoy tender

The Northern Lighthouse Board (NLB), the general lighthouse and navigation aids authority responsible for Scotland and the Isle of Man, has taken delivery of a new maintenance vessel built by Spanish shipyard Astilleros Gondán.

The 70-metre (230-foot) Pole Star was designed by Spanish naval architecture firm Seaplace and Danish counterpart OSK Design as a replacement for an earlier, similarly named vessel that had served the NLB for over 20 years and is nearing the end of her operational life.

“The owner required a modern, capable and environmentally advanced vessel to ensure the continuation and improvement of its vital safety service for mariners in Scottish and Isle of Man waters,” Seaplace told Baird Maritime.

“These operations take place in a highly demanding environment, where strong winds and heavy seas – especially during winter – can significantly restrict operational windows.”

Seaplace said that, from a design perspective, this leads to two key constraints: the need for a shallow draught to safely approach coastal areas that are often marked by rocky shoals and very limited depths; and the need to control the vessel’s behaviour during operations, particularly by minimising deck accelerations and reducing motions while the crew spends long periods at anchor.

“The owner’s brief was dominated by one fundamental requirement: achieving an extremely shallow draught. This constraint shaped the project from the very beginning.

Built with secondary survey and emergency response functions

“Starting from the owner’s initial design concept, we decided to increase the vessel’s beam in order to meet the required draught. At the same time, this limitation compelled both the shipyard and the engineering team to implement a very strict and continuous weight-control methodology throughout the project – a level of scrutiny that is not typically required in offshore vessel construction.”

“The owner’s brief was to deliver the vessel on schedule and to the required quality standards under a public tender framework, with a high degree of collaboration between the yard and the owner,” added Gondán. “As a private operator that had not commissioned a newbuild vessel since 2007, the owner relied on us to help translate operational needs into a modern build, incorporating the latest shipbuilding practices and technical advances.”

The builder said a key requirement was the owner’s active participation throughout the construction phase, with close engagement with the client team to ensure decisions, approvals, and changes were managed efficiently.

Pole Star’s main area of operation encompasses UK and Irish waters, though she is also capable of transiting to European and Scandinavian ports as well as operating worldwide in warm and temperate conditions.

“The vessel is primarily designed for buoy handling tasks and the maintenance of navigation aids, but also for inspections on offshore structures, hydrographic survey work, and lighthouse support using her dedicated workboat,” said Seaplace.

Full suite of navigation and positioning systems

The DP2-capable vessel is also equipped for first response firefighting, emergency towing, and integrating ROV/AUV operations thanks to her dedicated deck space and power supply. Her operational profiles range from short missions to longer deployments lasting up to 30 days at sea, often in rough conditions. Both the vessel and her systems were therefore designed with an emphasis on safety, seakeeping, and endurance.

“The vessel uses a hybrid-electric propulsion setup combining conventional diesel-mechanical power with a battery system,” Seaplace told Baird Maritime. “The main propulsion is DP2-oriented and based on two aft azimuthing thrusters (L-drive or rim-drive) with permanent-magnet motors providing 360-degree steering and high-efficiency, fixed-pitch contra-rotating propellers with optimised housings, vibration monitoring and low noise.”

Installed in the bow are two 515kW variable-speed transverse thrusters to provide additional manoeuvrability and redundancy.

“Overall, the arrangement ensures smooth low-speed control, excellent station keeping and efficient buoy handling operations, while the entire propulsion concept is also designed to minimise vibration and noise transmission to the hull, resulting in a surprisingly quiet vessel with a high level of crew comfort,” said Seaplace.

The vessel is equipped with a fully integrated Kongsberg bridge and navigation electronics suite designed to support safe navigation, DP operations, and advanced survey capabilities. The setup includes an integrated bridge system with dedicated navigation consoles, bridge chairs, and a complete set of navigation sensors and utilities.

Core navigation and positioning systems comprise DP capability, HIPAP acoustic positioning, multibeam echosounder, echo sounder and speed log, sound velocity sensor, a magnetic compass, and optical bearing devices, ensuring high-accuracy positioning and situational awareness.

“Altogether, this electronics configuration delivers a robust, redundant, and highly integrated navigation and control environment, suitable for complex operations, precise manoeuvring, and modern regulatory requirements,” said Gondán.

The electronics fitout also includes an Aimpoint CompM3 red-dot optic, which Gondán said is widely used for fast and reliable positioning.

The working deck is fully arranged for buoy handling operations and for supporting the vessel’s wider mission profile. The main equipment includes a central offshore knuckle boom crane for buoy handling, a dedicated knuckle boom crane for launching and recovering a small workboat, a chain/towing winch, a centre-line vertical chain roller, side rollers, chain stoppers, bulwark doors on both sides, tugger winches, mooring capstans, and removable towing guides.

“The cranes provide high-precision and outreach for lifting large buoys, as well as enabling the work boat to be launched and recovered safely and under control,” Seaplace remarked. “The combination of a chain winch, a vertical centre-line roller, side rollers and chain stoppers is also tailored for buoy handling, enabling the crew to manage heavy chains accurately and safely under load.

Layout guaranteeing enhanced safety

“The deck equipment is not generic offshore gear; it has been specifically selected for buoy servicing and offers high manoeuvrability and smooth motion control, as well as tools that enable the crew to work efficiently, even in challenging sea states.”

Seaplace said everything is designed strictly around operational efficiency and safety. One of the most distinctive aspects is that the buoys are stowed in dedicated moonpools, which can simplify handling, cleaning and maintenance. This setup keeps the deck clear, improves workflow during buoy swap-outs, and provides a safer and more controlled environment for the crew.

The bulwark doors and side recesses provide direct access at waterline level for buoy and ROV work, and are also used as gangway access points.

“Overall, the deck arrangement is very efficient and purpose-built for safe, continuous buoy-handling operations,” said Seaplace.

In Seaplace’s view, the main challenge came at the very beginning of the project, prior to contract signature, as some aspects posed issues despite the overall concept being well-developed.

“As a result, consolidating the design required us to rigorously justify every modification or alternative we proposed,” the designer told Baird Maritime. “Fortunately, the owner was highly collaborative throughout this early stage, and the discussions and refinements allowed us to achieve a consolidated design.”

“The biggest challenges in building the vessel were primarily related to its high level of technical complexity and system integration,” Gondán remarked. “The ship incorporates a large number of highly integrated onboard systems, requiring careful coordination between design, procurement, installation, and commissioning.

“A key challenge was the implementation of an advanced battery system enabling zero-emission navigation, which demanded rigorous safety engineering, space management, thermal control, and seamless integration with the hybrid power and energy-management systems. In addition, the vessel was required to comply with a classification society cyber notation, introducing demanding requirements in terms of network architecture, system segregation, cybersecurity risk assessment, and verification.”

Finally, the project included very high standards for onboard comfort and extremely low radiated noise levels, which significantly influenced structural design, machinery selection, insulation, and installation methods, and required extensive coordination and testing to achieve the specified performance.

“This project has been particularly rich from an engineering perspective,” said Seaplace. “It was our first major collaboration with Gondán , and the integration between their technical office and our own team worked exceptionally well.”

One of the key lessons Seaplace learned was that, in complex projects such as this, success comes when all parties focus on a common goal and work collaboratively.

“When that mindset is shared across companies, the project simply works better – and that is something we will certainly carry into future builds,” the designer told Baird Maritime.