The Turks originally had a defence walls roughly along the Defence Line built by the British East India Company (BEIC) between 1839 and 1848. This defence line ran across the width of the isthmus. The North Western end of the line was anchored on the Hadded Hill (Jebbel Hadded), which was the Western end of the Johar range of mountains. The South Eastern end was anchored on a spur running from the Mussoorie range. A gun battery was built at Ras El Erig to secure the Eastern flank. This defence front was split by a spur of volcanic rock running from the Mussoorie range northwards, ending at Ras el Gereff. This split the defence line creating the Large and Small Isthmus Positions which were linked by a tunnel 131 years (120 Metres) cut through the spur. There was a further tunnel some 348 yards (128) metres long to the rear (South) of the Small Isthmus Position. This longer tunnel under the Mussoorie range of hills allowed for troops to travel from the Crater area directly to the Small Isthmus Position.
In 1858 the Imperial British Government took over control of the Indian Army and this defence line therefore came under their remit and is mentioned in contemporary reports. By the 1880s Steamer Point had become the key point of coast defence and the original Isthmus Defence Line and its’ supporting batteries became less important. The old Isthmus Defence Line is referred to as a ‘palisade defence’ . Very few improvements appear to have be done to these defences since they were built and by the 1880 they appear to be poorly armed and maintained.
Between 1842 and the 1880s, the cost and responsibility for the defences appears to have rested largely with the Indian Authorities in Bombay. Very little was done to enhance or maintain these fortifications once they were built. In July 1881 Major-General F. Loch wrote that the fortifications and defences in Aden were “generally in a good state of preservation. However, the then went on to outline some of the problems that indicate that little had been done to enhance these fortifications in the intervening forty years. (British Library IOR/L/MIL/17/16/8 1882).
The large numbers of smoothbore artillery pieces that existed of nine different calibres, often mixed together in batteries. This made the supply of ammuniton complex.
Many of the guns are old smoothbore muzzle loaders “of little or no use again the ordnance of the present day”. There was a requirement to upgrade the artillery.
Most of the gun carriages and platforms dated back to 1844 and it was estimated they would only be able fire a dozen or so times before failing.
The Main Magazine, on the East side of the Isthmus Defences, was too small. The magazine was also too far away from the Steamer Point defences that were being enhanced.
This main Isthmus Defence Line is a well constructed parapet wall facing North with a dry moat to the front. Barracks and magazines were built to the rear, and two tunnels were used to facilitate communications. See plan in images. The Main Isthmus Defence Line had eight key components (information from British Library IOR/L/MIL/17/16/8 1882). :
Barrier Gate, Tower and Pier of Obstruction on the Western seaboard. A casemate battery was built in the guard house (tower) here and a battery of guns mounted on the pier facing North.
Western Gateway Redan with two guns in barbette positions with small magazine. Protected the entrance to the rear of the defences at the extremity of the Johar Range.
Southern Slope of Hadded Hill with llopholed defence wall running from the Gateway Redan up to the top of Hadded Hill. The face of the parapet wall is enhanced with scarping.
Hadded Hill emplacement enclosed within a three foot thick (one metre) parapet wall, largely loopholed.
Eastern Slope Hadded Hill with wall and dry ditch running down the East side of the hill with a sally port and drawbridge . The wall is a stepped banquette with steps and a parapet wall on both sides.
Victoria Bastion with six barbette gun emplacement, three on each face. Four guns in flanking casemates that fire along the dry moat.
Left Salient Angel with two gun embrasures, a six foot parapet wall. Has no magazine.
Left Demi-Bastion with four guns in barbette emplacements. Two gun in casemated positions fire along the dry moat. Magazine and casemate war shelter in the position.
Right Demi-Bastion with four barbette guns. Two guns in casemates to cover the dry ditch. A smally port with two wooden gates and ditch. A magazine a casemated war shelter.
Right Salient Angle with two guns and a 6ft parapet wall. No Magazine.
Right Redan with five guns in barbette emplacements. Also two casemated guns to cover the dry ditch which is 21 feet deep at this point. A loopholed wall some six feet high on the side of the position. A magazine and casemated war shelter.
The plan shows the general layout of the Isthmus Defences and some of the key features. The actual defence wall can be slip into the West and East die, separated by the rock outcrop of Ras El Girreff. The more shelters East side includes the stores building and main magazine.
There was a palisade fence on the West side running from the end of the defence wall to the shore line under Ras El Erig Battery.
Plan Isthmus Defence Line
