The Lighthouse
Vital Statistics
Description of the Rock
What's in a Name?
Marking the Spot
Scots Magazine "Account"
of 1807

1810 (1)
1810 (2)
1811 to 1823
Construction Techniques
The Lightroom
of 1811

Masonry Courses
The Railways of the
Bell Rock

The Bell Rock Lighthouse

Signal Tower/Shore Base
Machinery, Equipment
and Inventory

Keeping up with New Technology
Automation at the Bell Rock
Accidents, Attacks and Shipwrecks

Keeping up with New Technology

1811 onwards

The lighthouse was not originally painted but, by 1814, Stevenson noticed it was getting so discoloured that from then on he had it painted on a regular basis.

In 1842, the complete lighting apparatus (reflectors, lamps, and revolving machinery) was removed and shipped to Newfoundland, and for years it illuminated Bonavista Lighthouse until after 1872. The new mechanism in the Bell Rock had fully equalised light beams. About 1877, paraffin oil replaced the use of spermaceti oil.

A view of the kitchen in the tower
A view of the kitchen in the tower

From the time the light was first lit, until Saturday, April 5, 1890, the Bell Rock had never failed. In 1890, a tonite-explosive fog signal was installed. Tonite is a blasting explosive made from guncotton and barium nitrate. On that particular evening, this explosive went off prematurely, which considerably damaged the light room. It took until Sunday, April 13, before the light was repaired and operational again.

Major alterations

In 1902, the whole of the top part of the lighthouse was removed and the entire lighting mechanism taken out. The new dome and lantern were installed and the lighthouse continued to emit red and white beams from one of the finest lenticular apparatuses then made. The lenses were equiangular glass prisms, which had a focal distance of 1330mm. In this mechanism there was a centrally fixed incandescent paraffin lamp around which revolved the powerful lenses.

During these alterations, the two fog warning bells, which were now obsolete, were removed. One of these five hundredweight bells was gifted to the museum and when the old Arbroath Museum was given new life and rehoused in the Signal Tower complex, the fog bell was given pride of place in the Bell Rock room, where it can still be seen today. The new light flashed red and white every 60 seconds.

The changes of 1902 were full documented in the 1901 June edition of "The Engineer" - all of which has been transcribed below:

From: “The Engineer”- June 7, 1901 – pp. 585/6



"On the slopes of Gilmorhill, almost below the Glasgow University, and at an altitude which favourably lends itself to the efficient display of their capabilities, are placed two light towers, one of which contains a search-light projector of the Schuckert manufacture. This projector has a glass parabolic mirror 900 mm. in diameter, with iris screen, double disperser, and Venetian blind signalling apparatus, such as is fitted on men-of-war.

"The second tower referred to is more of the lighthouse order. In fact, the lantern, machine, lamps, and apparatus which constitute the exhibit are intended for the Bell Rock Lighthouse. These have been prepared mainly, and will be finally fitted up at this well-known lighthouse by Steven and Struthers, of Anderston Brass Foundry, Glasgow. The optical apparatus, which is the most interesting and novel feature about the exhibit, has been constructed by Lepante et Cie., of Paris; and the whole of the work is from designs by Messrs. D. and C. Stevensons, Edinburgh, the engineers to the Commissioners of the the Northern Lighthouse Board, &c.

"The Bell Rock Lighthouse is situated twelve miles from Arbroath, and stands on a dangerous reef which is little more than awash at low water, and covered to a depth of 10ft. at high water. The house was lighted for the first time in 1811, having taken four years to construct; and considering the position, and especially the period at which it was erected – when there were no steamers nor steam cranes available – it is a notable work. It is now the oldest existing rock lighthouse tower in Great Britain. The tower and apparatus were designed by Robert Stevenson, engineer to the Commissioners of Northern Lighthouses, and executed under his direct superintendence. With striking prescience, Stevenson seems to have realised the forces to which it would be exposed, proportioned his tower accordingly and introduced improvements in construction. This almost century-old lighthouse shows no signs of such weakness as has appeared in other towers – Smeaton's Eddystone, the Bishop Rock, &c. – involving their reconstruction. Although the tower is still quite equal to its purpose, the lantern and machine – which are the original ones, and are therefore, about 90 years old – show signs of requiring renewal. Both the lantern and machine and the apparatus are antiquated, and the light is too weak in power for a place of such maritime importance.

"The Commissioners accordingly resolved some time ago to renew these parts of the installation, and they are exhibited at Glasgow with the consent of the Commissioners.

Bell Rock lens 1902

The original diagram in the "The Enineer" magazine of 1901

"The optical apparatus has been designed specially by Messrs. Stevenson to suit the peculiar circumstances. The character of the light had to be maintained as it exists at present, viz., a red and white flash alternately, and of a maximum power consistent with one of the beams being red. It is somewhat of the bivalve type, but differs largely from anything yet constructed. It is a combination of two orders – hyper-radiant and first order. The white flash consists of 40 deg. of a hyper-radiant, the light from which is supplemented by back prisms of a size never before attempted. The red flash consists of 40 deg. of hyper-radiant, the light being intensified by totally reflecting prisms subtending 145 deg. Seeing a large portion of the light is lost by the red glass shades which naturally so far abstract a portion of the rays by absorption, the red flash is further intensified by dioptric mirrors of the best type.

"Although the glass work has been made in Paris the design is not French, but is, as has already been stated, but D. and C. Stevenson themselves, and it is worthy of note that with the exception of the totally reflecting prisms of the first-order portion, not one of the elements of the apparatus is of Fresnel's design.

"The flash of the new Bell Rock light will be about 112,000 candle-power, and is thus about five times the power of the most powerful red light on the French coast. The profiles of the whole prisms are designed for an index of refraction of 1-53, and the glass is set in a strong gun-metal framing. The whole face of glass through which the parallel rays from the burner are sent presents a surface of no less than 9 ft. by 9 ft., or 81 square feet of local opening.

"The apparatus – of which we give an illustration – stands on a cast iron table, which is made to revolve on conical steel rollers with ball bearings, between steel rings by a circular rack and pinion, driven by a clock machine. Antifriction roller bushes and ball bearing bushes are used in the construction of the different *journals. The fly-shaft makes 200 revolutions per minute, and absolute regularity of the machine will be attained when fitted at the lighthouse by means of the governing fans. The burners are six-wick patent Doty burners, and will be supplied with paraffin oil forced up by a pump driven off the main gear of the revolving machine.

"The apparatus and machine are enclosed in a lantern 13 ft. 6 in. diameter, which will be erected on the tower at the Bell Rock after the existing lantern has been removed. The lantern is sixteen-sided, the sash frames and astragals, which are triangularly made, and thus of the strongest form, are of gun-metal of such a proportion of parts as to attain a strength of 16 tons per square inch with an extension of at least 6 per cent. The frames are glazed with polished mirror plate glass; the dome is of sheet copper, of a spherical shape, surmounted by a ventilator to secure a proper draught and exclude the severest storm.

"The lightning conductor is ¾ in. diameter, and will be connected to the existing lightning rods of the Bell Rock. The Bell Rock tower through Stevenson's forethought was protected by a lightning rod inside as well as outside, so that all metallic bodies were in metallic connection. A somewhat similar arrangement was proposed by Faraday in 1844 for the Eddystone Lighthouse, and it would seem that the best electrical knowledge of the present day has not led to the suggestion of a better escape from one of the greatest dangers our lighthouse towers are subjected to.

"The fog signalling arrangement at the Bell rock will be maintained as at present, being an explosive signal of **tonite fired by an electrical battery, designed so that the signal cannot be fired until the charge is raised to the top of the lantern."

* journal – (mech,) that part of a shaft or axle which rests on the bearings.
** tonite – blasting explosive made from guncotton and barium nitrate.


Modernisation programme

In 1964, the Bell Rock again underwent major alterations. This modernisation had a dual purpose: to install a more efficient light mechanism, and to improve the living conditions of the keepers, as there had been little change within the tower since it was built. One of the panel of this (1964) dioptric lens is shown here. It was presented by the NLB in the first instance to the Old Kirk, in Arbroath; it was later moved to the Signal Tower Museum in 2004.

partial lens 1904

A single panel from the 1902 Bell Rock Lighthouse upgrade,
which is now on display in the Signal Tower Museum.

At this time, the Chicken Rock Lighthouse, a rock-station off the coast of the Isle of Man built by David and Thomas Stevenson, was being automated, and the first order, single-flashing apparatus became available. It was decided to use these eight beautiful panels of lenses mounted on a twin motor pedestal as the new Bell Rock light. These lenses revolve at 2 r.p.m. and show a single white light every three seconds that could be seen for up to 28 miles. A 3500-watt electric light bulb, mounted on a lampchanger, with a spare bulb beside it which would automatically swing into position should the primary bulb fail, was the source of illumination and the candle power emitted was 1,900,000. An emergency light was placed on the lantern dome, operated from standby batteries, to be used in case of complete failure of the main light.

The new layout after the 1964 alteration
The new layout after the 1964 alteration

Electrical generators were installed to provide power for the light and also for domestic needs. Twin 10.5 KVA diesel generators were set up in one apartment, with a 5 KVA unit, known affectionately as “Wee Knockie”, on the floor above.

To alleviate the problems of supplying the Bell Rock with fuel and water, etc., especially in winter, it was decided to excavate into the solid sandstone base of the lighthouse to provide a 1,100-gallon tank for fuel oil. This was in addition to the purpose built tanks, fitted to the outside of the cast-iron murette, which held 1200 gallons. This was enough to last 7 or even 8 months. Storage of fresh water was increased from 260 gallons to 690 gallons using storage tanks in the lightroom and a tank in the storeroom below. A salt-water evaporator was also installed but in practice it was found to use too much fuel, and it was used only in an emergency.

The fog signals were also changed, as the Tonite system was now obsolete. Three tyfon devices were installed round the lower lantern walkway. This mechanism uses compressed air to produce sound on a resonator. It is electrically operated and gives a single blast two seconds long every minute. The rooms in the lighthouse were switched round and the order from top to bottom was as follows: The Light-room; Control-room; Living room; Bedrooms; Store Room; Upper Engine Room; Lower Engine Room; Access Shaft; Entrance. The living-room/kitchen was moved to immediately below the old light-room and, instead of using coal as fuel, cooking was now done by gas. The old light-room had the optical apparatus installed in its upper level, and the sophisticated radio controlled machinery was installed immediately below the light mechanism.

The Bell Rock acted as a coastal weather recording station for the Meteorological Office, making hourly weather reports to Leuchars. Recently this has been taken over by St Abb’s Lighthouse. Eventually, in the control room, an exercise bicycle was added to allow the keepers some healthy exercise as you couldn’t walk far on the Rock. The bedrooms were completely refurbished with three bunks in tiers, each in its own tiny compartment. Electric power brought television, which was a great bonus to keepers living in such isolation. The original stone spiral staircase leading up to the first room was also taken out. This allowed the construction of an additional half-floor where a salt-water toilet was installed.

The Bell Rock lighthouse still uses the system of gratings round the rock surface to provide level walkways. In 1975 a helipad was constructed although it can only be used at low water and is always dependent on the wind and weather being suitable. Radar beacons (or Racons) were installed. Continuing the tradition of keeping abreast of innovative technology, the Bell Rock has once again gone through a period of major change. This oldest existing rock lighthouse in Britain has become fully automatic. During early summer of 1987 the complete light mechanism was once again removed. In July of that year the Bell Rock was lit by a temporary light, whilst the new light mechanism was being installed.

The Automatic Bell Rock Lighthouse

The lighthouse was de-manned on the 26th October 1988. A Dalen optic was installed, replacing the existing electric light of 1964. This type of light, named after its Swedish inventor, uses pressure from dissolved acetylene gas to revolve the lens before passing to a mantle type of burner. The flash is white - every 5 seconds - and has a nominal range of 18 miles. Remote electronic monitoring takes place from the Northern Lighthouse Board Headquarters in Edinburgh via Fifeness Lighthouse. Maintenance is carried out annually. There are no fog signals at the Bell Rock now, and radar beacons (Racons) continue to be used. These are triggered by radar on vessels, giving a range and bearing from the lighthouse which is displayed on the ships’ or boats’ radar screen. This type of signal is vastly superior to what had gone before, as it is totally unaffected by weather conditions.

At the end of 1999 a new round of changes began at the Bell. This refurbishment means that the Bell, in effect, is now eco-friendly. The light, once powered by acetylene gas, has been removed and the optic is now powered from batteries charged by solar panels, helped along during the long winter months by generators. The work started by installing new batteries in the battery room; followed by the re-installation of new generators. It is interesting to note, that when the light was de-manned, the generator sets were removed and the room they occupied was converted to a gas room which was used to house the acetylene cylinders (which in turn powered the optic). The present arrangement removed the gas cylinders, and the room has been converted back to an engine room, which now houses two 10kW generators. As they say: Plus ça change, plus c'est la même chose. (The more things change the more they remain the same).

For a full update of the latest changes at the Bell Rock - see Automation

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