The Viper was originally ordered as the third hull of the Krait Class. It differed from the others, as to speed up production it was to make use of four turrets cannibalised from the Liu Class. It was decided that was not a good idea and an even better idea was to repurpose the hull as an aircraft carrier. The Khmer designers had three years of information on other conversions to base their thoughts on. One of the main sources of inspiration was the design of HMS Hermes. Construction of the hull to an aircraft carrier started seriously in 1920. The hull was built up to include a 19 foot hangar running the length of the ship. This being broken in two places, where elevators to take aircraft from the hangar to the flight deck, were fitted. A deck was set above that for accommodation, ready rooms, and any other function that could be thought of. A set of aircraft similar to those being built for the French Bearn were acquired for the ship. Virtually double the number required were ordered as it was felt that 'some' training accidents might occur to reduce the number of aircraft in service.
The ship was due to enter service in 1924 after builders trials. Once the ship reached its full load displacement, serous instability problems became apparent and the ship went back into dock to be fitted with bulges to aid stability. Once that problem was cured, the ship started to work with the fleet. This was to figure out how best the Viper and its aircraft could be used to aid the Fleet in its defence of the Empire. The Empire had many hundreds of miles of coastline to protect. All of those miles of coastline could be covered by land based aircraft. What the Viper could do was to bring localised air superiority to where an invader may have made landings on the Empires coastline. That way opening up the area for the battle squadrons to defeat the invader. That ignores that the invader might have aircraft carrier(s) of their own that already has taken air superiority. But their thinking was in the right place.
The original armament was purely self defensive. Four 4" AA guns and ten 25mm AA cannons, and that was it. It was not until the ships late 1930's rebuild that the armament was upgraded as the recognition of aircraft as being a warships biggest enemy was shown.
The first job for the Viper was to clear out the Pirates of Borneo and Philippines. That was a job the Fleet took great delight in accomplishing. After all, the Pirates were competitors for the same income that Khmer levied on shipping passing through its territorial waters. Khmer could not make any money off of a ship that the Pirates had stolen.
The 1937-38 rebuild added some much needed firepower and command structures to the old ship. New bridge superstructure, similar to that fitted to later ships, replaced the old bridge. It was the ships armament and aircraft handling facilities that got the largest upgrades. The change from the single 4" AA around the bridge to the twin 4" in sponsons along the side of the ship, triple the heavy AA. The mounting of four quad 40mm mountings made a huge difference especially when predictors were fitted in 1942. The old 25mm were upgraded to the latest mark which fired twice as fast as the original model placed aboard ship in the early 1920's. The change there was fitting twin mountings in place of the singles.
The Viper allowed the Khmer Navy to test and trial how to project air power. In 1939-40 the last pieces of the puzzle for the Khmer Navies future were purchased. Dewoitine 520 fighters, and Latecoere 298 bombers, plus the rights to build those aircraft locally. The Latecoere was used as both a seaplane and wheeled versions by the French and Khmer Navies, and had the capability to be both a torpedo bomber and dive bomber. These aircraft were the equal or better than anything aboard their rivals ships.
The fitting of all the new equipment brought back the old instability problems, which were ignored and led to the loss of the ship from a single torpedo hit. But whose torpedo was it?
