RKS Bunsi (CL-1921)

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The six ship Bunsi Class came in two batches. The first, Bunsi, batch was armed with the 45 caliber 5.5" guns, the same as those fitted to the Sanphet Class. The second group featured the new 50 caliber 5.1" guns in the same twin turret but upgraded with a 50 degree elevation for barrage firing but was not a true dual purpose weapon. This twin turret debuted on the 1921 Krait class battlecruisers. The way to tell the difference between the two turrets, the 5.5" had a canvas shroud over the gun ports. These were built to be fast so they could act as flotilla cruisers when the need arose.

Once the Capital ships had their orders filled for the new Dual Purpose turrets, they then started to filter down to the cruisers. From about 1935 onwards, one to three ships a year were converted with the dual purpose 5.1" turrets. Once all the conversions were complete, the class was all one main armament.

Okay, so I have done all these conversions and now have 50 odd x 5.1"/5.5" twin low angle turrets available (more if I include the destroyers I have yet to draw), what do I do with them? It is a question I have asked myself many times. Especially with a 5" sized gun. The shells they fire are not really big enough to do a lot of damage to cruiser sized vessels and above. So as harbour defence weapons they would suck. The other problem is the amount of work required to create a shore based mounting for a turret. The shell handling has to be done beneath the turret - lots of concrete. My normal thought is to strip the guns themselves out of the turrets, scrap the turrets not required, then mount the guns in whatever new type of mounting might be suitable for their next bit of service to Emperor and Empire.

I do a lot of reading about all of the different guns and turrets/shields they are used in. One of the major differences in the type of gun is the angle that the gun can be loaded at. That can be anything from 0 degrees (flat line) or through to 90 degrees (vertical). Most later dual purpose guns had a loading angle equal to the maximum elevation. It is the earlier low angle weapons that had 0-30, 0-40, 0-50 degree elevation that would also have their loading angles at the same rate, whatever the mounting may have been rated at. You could remove the gun from its mounting and put it into a turret with a higher elevation, but the gun would still have a maximum loading elevation rate as before. Not a good thing to have your shell fall out when trying to load it. Where I have increased the range of battleship guns, by increasing the elevation, the elevation that the guns can be reloaded at might not always change. A gun with a 20 degree elevation could be increased to 30 degree elevation but might still only have a maximum loading angle of 20 degrees. So your gun is loaded raised to 30 degrees, fired, lowered to the 20 degree angle for loading, then raised again. This was not a great problem as the guns could be raised and lowered about 5 degrees a second, rate of fire for a large gun being about 2-3 rounds a minute.

So while all of these 5.1"-5.5" guns could be fitted into different mountings their usefulness would still be tied to the guns original specifications. The 5.5" never had AA shells made for them, so they would always be limited to surface actions. It is the 5.1", which does have an AA shell produced for it, which is of much more use to the Empire. Those original twin turrets could have had quite a lot of work done to them to increase the elevation and so make them more useful as AA weapons. This would require the gun ports to be cut higher into the turret and the floor of the turret would need to be lowered into the barbette/shell handling room. All of the shell handling areas from the turret down would also need to be changed to reflect the new turret floor height. Whether that work is more expensive than just lowering a new turret into place on a barbette that was designed to be used on the older cruisers, I don't know enough about. Most information on guns/turrets does not include the costs of production. Even with all this work done the turrets might still not have the 75 degree plus elevation required to be termed a true AA gun .For me, the new turret would be the way to go. No having to raise or lower the guns for reloading, shell handling is already in place. No mucking around. Point and shoot.

The 5.1" guns removed/stripped out could be fitted to AA mountings used as shore based weapons for heavy AA fire and support around ports and manufacturing centers. Merchant ships had weapons fitted to them for local defence and there is no reason why both the 5.5" and 5.1" could not be used for this duty. I would think the Empire would find many innovative ways to make use of the old weapons.



The evolution of the Bunsi class from low angle cruisers to AA cruisers was long and protracted. The conversions started in 1935 and finished in 1939. Besides the new turrets being fitted, dual purpose directors also were required to make best use of he new guns. The single 3" had to be retained till 1939 when they were replaced with four twin turrets of the new Bofors 40mm. Radar predictors for the 40mm were not fitted till late 1941. Early 1942 the torpedoes are removed and replaced with two quad 40mm in their place. Radar assistance is given to the Dual Purpose Directors, while targeting radar is fitted for and aft, search radar now adorns the mast tops. The ships, by the end of 1942, have all the radar types they should have, these are upgraded and replaced through to the end of the war to the ones that survived..

 

The Pheuak is the White Elephant which is part of the Royal Standard of Khmer.




 

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