Please do not use the ones invented by modellers, e.g. DKM, IJN, or HIJMS etc. Simple rule: if the abbreviation is English and the language of the country is not English, the prefix is not the official one (rules out most of the HxxMS).
By the way: SMS was also used by the Austrian-Hungarian Navy (using the same German abbreviation), as HMS is also used by the Swedish navy (because the abbreviation is the same, it means Hans/Hennes Majestäts Skepp).
There is an short article about that in one of the last Warship (2015?).