Page 28 - Hilsea Lines and Portsbridge
P. 28

Hilsea Lines and Portsbridge                                                                       Solent Papers No.4

         7-inch R.B.L. gun on casemate platform (Fort Nelson)  Embrasure for 7-inch R.B.L. in Centre Bastion


         An ingenious mirror sighting system allowed the gun to  position. Movable armament was also provided and this
         be laid onto the target, from a raised platform at the rear  consisted of eight 40 pounder RML’s and four 6.6-inch
         of the gun mounting, without the gunlayer being       howitzers on travelling carriages.
         exposed to enemy fire. The mounting rotated on four,
         toothed wheels, running on sweeper plates let into the  All the armament was removed in 1903 and the Hilsea
         base of the emplacement. A hand operated set of gears  Lines were not rearmed except for the fitting of certain
         imparted movement to the mounting and allowed it to be  guns during the First and Second World War. Armament
         traversed and a training arc, marked off in degrees   lists for 1912 to 1916 state that Hilsea Lines had four
         allowed for the accurate positioning of the gun.      machine guns. Also a single 3-inch AA gun was
                                                               mounted at the top of the access ramp at East Bastion,
         The casemate armament was to be 7-inch RBL’s on       overlooking the airfield and a one pounder pom-pom
         casemate traversing platforms (slide) and these       gun on a movable mounting was placed on West
         permitted the guns to be trained horizontally and also  Demi-Bastion. A 6pr Hotchkiss for AA defence was also
         checked the recoil. The gun was mounted on a carriage  listed in 1916. WWII armament consisted of two ex:
         which slid up and down the inclined plane of the      American (or French) 75mm guns of WWI vintage, one
         traversing platform, where friction plates damped down  mounted in a concrete emplacement on East Bastion
         the movement. When the gun fired, the recoil pushed the  (SU668040), and one on West Demi-Bastion
         carriage back up the platform, where it  came to rest.  (SU652044) close to the trig point. Both sites also have
         The gun could then be sponged out and reloaded. When  holdfasts for earlier guns, possibly a 1pr Pom Pom or
         this was finished, the gun was slid back to its firing  6pr Hotchkiss.

                        7-inch Rifled Breech-loading gun on a Casemate Traversing Platform and Carriage

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