Close this search box.
Close this search box.

HMS Inflexible : Thickest Armored Belt Ever Fitted To A Warship

HMS Inflexible : Thickest Armored Belt Ever Fitted To A Warship


This illustration of HMS Inflexible appeared after page 386 in Thomas Brassey’s The British Navy, Volume I.

The daddy of them all, HMS Inflexible. Still to this day the ship with the thickest armored belt ever fitted to a warship, a massive 24 inches of armor backed by 17 inches of teak along the waterline.  

Her first commanding officer was a certain Captain J. A. Fisher who would later push the concept we all love – The Battlecruiser – as Admiral Jackie Fisher.

Launch Day in Portsmouth

She was armed with RML 16-inch 80-ton guns which were large rifled muzzle-loading guns. Due to their length the guns could not be reloaded from inside the turrets. Reloading was done using hydraulic rams fitted outside the two turrets underneath an armored glacis. 

Drawing depicting one of the gun turrets

These monster guns were intended to give the largest British Battleships parity with the large guns being mounted by Italian and French ships in the Mediterranean Sea in the 1870s.

Turret cross-section showing guns pointing downwards for reloading

HMS Inflexible with four guns became the only ship to mount them, in 1880. By that time such muzzle-loading guns were already obsolete. Moreover, and were being superseded by a new generation of rifled breech loading guns.

 late in her career while serving as port guard ship at Portsmouth between 1893 and 1897.

Her huge guns proved useful when she bombarded Alexandria in 1882, an action that was to last for over ten hours with her firing over eighty-eight 16-inch shells. Unfortunately, like many guns of the time their blast caused much structural damage to Inflexible and smashed many of her own boats. 

A view of Inflexible from broad on her port quarter sometime prior to the 1885 removal of her full sailing rig.

The first ship in the navy to be lit by electric lighting, she was also fitted with submerged torpedo tubes and probably the most notable feature was the underwater amour deck running from the ram bow to the stern.

In addition, the electrical installation provided 800 volts DC to power arc lamps in the engine and boiler rooms and Swan incandescent bulbs in other parts of the ship. 

Inflexible in 1881

The circuitry was complicated because the lighting consisted of sets of 18 Swan lamps and an arc lamp arranged in series.

HMS Inflexible, at SpitheadInflexible took part in the 1882 Bombardment of Alexandria. Painted by Charles Edward Dixon.

Each incandescent bulb was fitted with an automatic mechanism to switch in a resistor to maintain continuity should it fail, so that the set of 19 lights would not be extinguished if one failed. 


Her bow photographed during her fitting out.

The arrangement also led to the first fatal electrocution on a Royal Navy ship, in 1882, after which the Navy adopted an 80 volt standard for its ships.

Plans of Inflexible as shown in Brassey’s Naval Annual
Steam Trials, Stokes Bay Run :

5th February 1880

Displacement: 11,147 tons

IHP: 7,267

Speed: 14.97 knots.

15th February 1880

Displacement: 11,138 tons

IHP: 7,710

Speed: 15.04 knots.

Written by Bass Moog

With Contribution from Alex Ray

Battleship Richelieu

Thank you Imperial War Museums (!