Nab Tower
Nab Tower is one of the most striking and unusual structures in British waters, rising from the Solent at the eastern approaches to Spithead and the Portsmouth harbour entrance. It is a large, squat, circular sea fort — a reinforced concrete tower sitting on a steel caisson foundation — that stands alone in open water roughly seven miles south-east of Portsmouth and about four miles north-east of the Isle of Wight. Visible from the shores of both the mainland and the island, Nab Tower serves today as a lighthouse and navigational aid, warning ships away from the treacherous Nab Rock shoal around which it is built. Its looming, industrial profile — more fortress than lighthouse — makes it one of the most distinctive landmarks of the Solent, and its strange history gives it a significance far beyond its lonely appearance on the water.
The tower's origins are rooted in the urgency of the First World War. By 1917, German U-boats were wreaking havoc on British shipping, and the Admiralty devised an ambitious plan to construct a line of massive forts across the English Channel between Folkestone and Cap Gris-Nez. These anti-submarine forts, known as the M-N Line project, were to be built in dry docks, floated out, and sunk onto the seabed to create a continuous barrier. Construction began, but the war ended in November 1918 before the line could be completed. Several of the concrete caisson structures had already been built or were under construction. One of these — intended to be a mid-Channel fort — was repurposed and towed from its construction site at Shoreham to the site of the Nab Rock, where it was sunk into position in 1920 and converted into a lighthouse. The result is a structure whose design philosophy was purely military but whose final role became entirely peaceful and navigational.
Physically, Nab Tower is a formidable and somewhat eerie presence on the water. The lower section is a vast cylindrical concrete caisson, grey and barnacled, rising perhaps fifteen metres above the surface of the sea. Above this sits the habitable and operational tower itself, a multi-storey cylindrical structure with rows of small windows, painted in the red-and-white banding of Trinity House lighthouse livery. The whole ensemble looks nothing like a conventional lighthouse — there is no elegant tapering column, no graceful lantern room perched on a slender shaft. Instead it resembles a squat industrial keep or a stranded warship superstructure. In heavy weather, waves crash against its base and spray climbs its concrete flanks; in calm summer weather it sits still and hazy on the glittering water, its foghorn and its light serving the constant procession of commercial vessels, ferries and yachts that use the eastern Solent. Trinity House, the authority responsible for lighthouses in England, Wales, Channel Islands and Gibraltar, has managed Nab Tower for many decades, and the light is now automated.
The waters around Nab Tower see some of the busiest maritime traffic in the world. The Solent is a major shipping thoroughfare connecting the English Channel with the ports of Southampton and Portsmouth, and vessels of every conceivable size pass the tower around the clock — container ships, P&O and Wightlink car ferries, naval vessels from the nearby Royal Navy base at Portsmouth, leisure yachts, and racing dinghies. The Isle of Wight lies a short distance to the south, and the low green hills of the island form a backdrop in that direction. Northward, the chalk downs of Hampshire and the urban sprawl of Portsmouth are visible on clear days. The sea here is tidal and often turbulent, with strong currents running through the eastern Solent entrance; the Nab Rock itself, around which the tower is built, was responsible for numerous wrecks in earlier centuries.
The tower is not open to the public and cannot be visited on foot — it stands entirely in open water with no causeway or land connection, and Trinity House does not operate public access. However, it is a well-known and photogenic waypoint for yachtspeople and boaters transiting the Solent, and it features prominently in sailing charts of the area. During the famous Fastnet Race and other offshore sailing events that begin and end in the Solent, Nab Tower is a key navigational reference point. It can also be seen clearly from the eastern tip of the Isle of Wight, particularly from the area around Bembridge and St Helens, and from the seafront at Hayling Island on the mainland. Boat trips around the Solent, particularly those departing from Portsmouth or Gosport, often pass close enough to give passengers an impressive view.
One of the more poignant and curious chapters in Nab Tower's history involves the Second World War. During the Dunkirk evacuation of May and June 1940, the tower served as a way-marker for the armada of small ships making the perilous crossing to the beaches of northern France. It also served as a reference point for the extraordinary Mulberry harbour operations in 1944 ahead of the D-Day landings; the concrete Phoenix caissons towed across to Normandy were conceptual descendants of the very technology used to build Nab Tower itself. There is thus a neat historical thread connecting this isolated tower with some of the most dramatic moments of twentieth-century British history.
The tower also has an atmospheric significance in literature and culture. The poet and novelist Alfred, Lord Tennyson lived for many years at Farringford on the Isle of Wight and walked the downs overlooking the Solent, and the sea-marks and forts of these waters formed part of the visual world he inhabited. The Solent and its towers have inspired artists, writers and mariners across generations. Though Nab Tower itself postdates Tennyson, it has become part of that layered seascape. For anyone who sails or motors through the eastern Solent, rounding the Nab is a moment of passage — leaving behind the sheltered waters and entering the open Channel, or returning from it — and the tower looms as both landmark and guardian of that threshold.