The inner and outer breakwater, including the coaling shed, storehouse jetty, coaling jetty, inner breakwater fort and outer breakwater fort

Portland's inner and outer breakwater form a monumental harbour defence system constructed between 1849 and 1882. The project was designed by Chief Engineer James Meadow Rendel, who was succeeded by John Coode in 1856. The civil engineer John Towlerton Leather carried out the construction. The outer breakwater fort was designed by Captain E H Steward. The breakwaters underwent alterations and additions in the late 19th, 20th and 21st centuries, though all post-1945 buildings, structures and plant added to these structures are excluded from the listing.

Layout

The inner breakwater, including the storehouse jetty which forms the return to the west into The Camber, and the inner breakwater fort at the outer north-east end, has a total length of approximately 750 metres. Separated by the South Ship Channel, the outer breakwater forms a continuation of the inner breakwater and runs from south to north, curving towards the west at its southern end. At the northern end stands the outer breakwater fort, and extending to the south-west is an L-shaped jetty. The outer breakwater has a total length of approximately 1,820 metres.

The Storehouse Jetty

The storehouse jetty at the western extent of the inner breakwater is constructed of large, bolstered roach stone blocks to a battered face. The west end was rebuilt in 1906. Some of the timber stubs of the mid-19th century coaling stages survive to either side.

The Coaling Shed

The coaling shed is constructed of Portland rubble stone with ashlar dressings. Originally it had a slate roof, now replaced with corrugated iron. It is a long 11-bay stone structure arranged in two parallel ranges with gabled west and east ends; the east gable has been rebuilt in brick above the eaves line. The roof is divided by two raised and coped 'party divisions' which do not correspond with the main bay articulation.

The south elevation has eleven sunken panels divided by a high band, and a series of segmental-headed openings near ground level, plus four larger openings in bays 3, 4, 6 and 8. At the right-hand end is a single-storey breeze-block addition. The north elevation matches the south, with the addition of two staircases to the upper doors. The west gable has a pair of large lunette windows, beneath which are the timber stubs of the platform used to transfer coal to the shed. Both the west and east ends have three ground-floor arched openings with keystones; the central arch is wider than the outer two and corresponds to the layout of the internal tunnels.

The ground floor of the coaling shed has a main axial brick-vaulted tunnel with stone surrounds to segmental-arched openings leading into the narrower side tunnels. The upper floor, originally a coal store, is divided longitudinally by raised baulks and heavy axial timbers with braces supporting a double king post roof with joists in iron shoes. The rails for the former coal wagons and other original parts of the coaling system also remain. The lube oil storage tanks to the eastern end of the coaling shed and the alterations to provide office accommodation are not of special interest and excluded from the listing.

The Inner Breakwater

The inner breakwater continues towards the east, and its stone construction has large bolstered stone blocks to a battered seaward face. The upper, elevated section is the Prince Consort Walk and at its western end is a carved commemorative stone. On its west face is the Royal Coat of Arms and on the north face is the inscription:

"FROM THIS SPOT / ON THE 25TH JULY 1849 / HIS ROYAL HIGHNESS PRINCE ALBERT, / CONSORT OF QUEEN VICTORIA / SUNK THE FIRST STONE OF THIS BREAKWATER. / UPON THE SAME SPOT / ALBERT EDWARD, PRINCE OF WALES, / ON THE 18TH AUGUST 1872 / LAID THIS LAST STONE / AND DECLARED THE WORK COMPLETE. / THESE ARE THE IMPERIAL WORKS / AND WORTHY (OF) KINGS."

The east face is inscribed:

"JAMES MEADOW RENDEL / DESIGNED THIS WORK / AND DIRECTED ITS EXECUTION / TILL HIS DEATH IN 1856. / JOHN COODE, / THE RESIDENT ENGINEER FROM ITS COMMENCEMENT, / THEN SUCCEEDED TO ITS CHARGE / AND COMPLETED IT. / J.T. LEATHER WAS THE / CONTRACTOR FOR THE WORK."

The inner face of the breakwater has brick-vaulted, stone storage chambers with segmental arched openings with keystones. The chambers are divided by battered piers. Some of the openings have been walled across with brick or concrete, and some have had modern plant inserted; these later alterations are not of interest and excluded from the listing. Above is a stone cornice, and projecting from and beneath the cornice are the timber stubs of the staging that supported the hydraulic chute system to the coaling jetty where coal was transferred to the ships. The inner walkway is paved with stone setts, although the inner section is now covered with tarmac.

The Inner Breakwater Fort

The inner breakwater fort is built of roach stone and granite. The circular fort has a diameter of 35 metres and is accessed from the breakwater via a stone staircase and wooden bridge, replacing an earlier sliding bridge. To either side of the drawbridge are flanking walls with granite cones projecting from the coping stones. A segmental arched opening, partially infilled with brick, gives access to the gun floor that retains the shell and cartridge hoists from 1897, the mountings for the quick-firers, and the concrete glacis—a sloping surface—to its southern side. A plaque has been added to the gun floor inscribed:

"THIS STONE COMMEMORATES THE VISIT BY / HIS ROYAL HIGHNESS / THE PRINCE PHILIP DUKE OF EDINBURGH / ON 14TH JULY 1999 / TO CELEBRATE THE 150TH ANNIVERSARY OF / THE LAYING OF THE FIRST STONE OF / THE PORTLAND BREAKWATERS / BY / THE PRINCE ALBERT THE PRINCE CONSORT"

To the centre of the gun floor is an iron cover which provides access to the magazine below. The magazine has a cross plan with a stone spiral staircase within a brick stairwell to its centre. The southern arm has been filled with concrete as has part of the eastern arm, but it retains cartridge and shell stores.

The Outer Breakwater

The outer breakwater similarly consists of an inner pier and an elevated section on the seaward side. It is built of large boulders, and the outer face is sloped towards the sea and is mortared in places. The inner face of the elevated section is largely of cut and coursed stone, with some sections of strewn boulders. There is evidence of repair and rebuilding along its length. On the elevated section survive some of the timber piles for the original staging for the rails, and there are baulks of timbers.

The circular pierhead at the south end is faced in granite and has a Second World War concrete searchlight, as well as the winches and bollards associated with working the boom that closes the South Ship Channel. Behind the pierhead is a small landing stage, and a ramp along the inner face of the breakwater. There are the ruins of an unroofed ashlar building. Further towards the north are 20th century searchlights and observation posts. At the northern end, which terminates with the outer breakwater fort, are a series of 19th and 20th century buildings of brick, stone and concrete which includes a single-storey, four-bay building of rusticated stone with ashlar to the openings, and internally, a fireplace and niches. To the inner face of the outer breakwater, at the northern end, is a triangular landing platform.

The Outer Breakwater Fort

The outer breakwater fort is constructed on a concrete substructure that is faced in granite. Above is the cast iron fort which comprises two rings of iron box-girders, supplied by Jeavons & Co. of Millwall, fanning from a central octagonal well. The walls are three thicknesses of 15-centimetre iron plates, supplied by Messrs Brown of Sheffield. The iron roof is capped with concrete, and on top of the roof is a Second World War pre-cast concrete coastal artillery searchlight.

Internally, the central well is faced with ashlar with rusticated roach stone forming the quoins and keystones to the arched openings to the gun rooms and ports for fourteen guns. There is concave fluting to the sloping ceiling to the gunports, supported by pillars between the casements. The lower level has shell and cartridge stores and separate passages and lifts for both. To the centre is the former engine room. Both levels of the fort are connected by a spiral cast-iron staircase. The fort retains many fixtures and fittings including doors, slatted timber floors to guard against explosions, pegs for hanging clothes changed when ammunition was being handled, and an original lamp in the lamp passage, as well as shell hoists.

The buildings to either side of the ramp leading from the west entrance of the fort to the L-shaped jetty are early 20th century garrison buildings. The ramp leads down to a two-tier structure. On the upper floor is a late 19th century gun emplacement with associated magazine stores and a 20th century concrete-rendered brick building added to the ground floor of an earlier stone building. To the lower floor are three segmental arched openings, behind which are stores and ablutions. The position of the capstan and winch which transferred the guns onto rails up the slow-rising staircase and ramp to the right is evident in grooves to the side of the jetty.

The jetty continues to the west over three segmental arches with quoins and keystones. Above is a flat-roofed, altered brick building and a three-bay, flat-roofed stone building with rusticated quoins to the openings. To the rear wall of the jetty are the winches for the boom. The jetty continues to the south.

Excluded Features

All post-1945 buildings, structures and plant added to the inner and outer breakwater, the coaling shed, storehouse jetty, coaling jetty, inner breakwater fort and outer breakwater fort are not of special architectural or historic interest. These include: the small brick lean-to attached to the east end of the coaling shed; the oiling jetty attached to the storehouse jetty; the detached late 20th century building with corrugated iron roof to the east of the coaling shed; the brick and concrete walling across the openings of some of the storage chambers and the inserted modern plant; the fuelling jetty and associated pipelines; and the mid-20th century building, known as the salvage shed, attached to the inner face of the inner breakwater at its eastern extent.