The current, fourth lighthouse was designed by
James Douglass (using
Robert Stevenson's developments of Smeaton's techniques). This lighthouse is still in use.
Design and building By July 1878 the new site, on the South Rock was being prepared during the 3½ hours between
ebb and
flood tide; the
foundation stone was laid on 19 August the following year by
The Duke of Edinburgh, Master of Trinity House. The tower, which is high, contains a total of 62,133 cubic feet of granite, weighing 4,668 tons. It contained a six-sided biform (i.e. two-tier) rotating optic of the
first-order, high and weighing over seven tons. Each of the six sides of the optic was divided into two
Fresnel lens panels, which provided the light's characteristic of two flashes every thirty seconds. The optic was manufactured by
Chance Brothers of
Smethwick and designed by their chief engineer
John Hopkinson FRS. At the time the Eddystone's extra-tall () lenses were the largest in existence; their superior height was achieved through the use of extra-dense
flint glass in the upper and lower portions of each panel. The light had a range of . This was said to represent 'the first practical application of superposed lenses of the first order with oil as the illuminating material'. In addition to the main light a fixed white light was shone from a room on the eighth storey of the tower (using a pair of
Argand lamps and
reflectors) in the direction of the hazardous
Hand Deeps. The lighthouse was also provided with a pair of large bells, each weighing two tons, by
Gillett, Bland & Co., which were suspended from either side of the lantern gallery to serve as a
fog signal; they sounded (to match the
light characteristic of the lighthouse) twice every thirty seconds in foggy weather, and were struck by the same clockwork mechanism that drove the rotation of the lenses. The mechanism required winding every hour (or every forty minutes, when the bells were in use), 'the weight to be lifted being equal to one ton'; shortly after opening, the lighthouse was equipped with a 0.5 h.p.
caloric engine, designed 'for relieving the keepers of the excessive strain of driving the machine when both illuminating apparatus and fog bell are in use'.
Later modifications In 1894 an explosive fog signal device was installed on the gallery of lighthouse; the fog bells were briefly retained as a standby provision, but then removed. Later, beginning in 1959, the light was electrified: the new light source was a 1,250W
incandescent lamp, powered by a diesel generator (three of which were installed in a lower store room). (it was exhibited on the
Royal Pier in the 1970s, but later removed to a council yard where it was destroyed by vandals). The lighthouse was automated in 1982, the first
Trinity House 'Rock' (or offshore) lighthouse to be converted. Two years earlier the tower had been changed by construction of a
helipad above the lantern, to allow maintenance crews access; the helipad has a weight limit of 3600 kg (3½ tons). As part of the automation of the lighthouse a new electric fog signal was installed and a metal halide
discharge lamp replaced the incandescent light bulb formerly in use. The light and other systems were monitored remotely, initially by Trinity House staff at the nearby
Penlee Point fog signal station. Since 1999 the lighthouse has run on solar power.
Present day The tower is high, and
its white light flashes twice every 10 seconds. The light is visible to , and is supplemented by a
foghorn of 3 blasts every 62 seconds. A subsidiary red
sector light shines from a window in the tower to highlight the
Hand Deeps hazard to the west-northwest. The lighthouse is now monitored and controlled from the Trinity House Operations Control Centre at Harwich in Essex. == References in media ==