HSwMS Garmer was a small river monitor built for the Swedish Royal Skerry Artillery in the mid-1860s.

This force was to be equipped with ten small monitors to operate in shallow waters that could navigate the Göta Canal system that linked Gothenburg (Swedish: Göteborg) on the west coast to Söderköping on the Baltic Sea.

A report to the Parliament of Sweden described her as lacking a keel, flat-bottomed amidships and had a sharp bow and stern.

She was armed with a single muzzle-loading 267-millimeter (10.5 in) M/66 smoothbore gun mounted in a long, fixed, oval-shaped turret.

The machine gun weighed 115 kilograms (254 lb) and had a rate of fire of 500 rounds per minute.

[2] Garmer had a complete waterline armor belt of wrought iron that was 39 millimeters (1.5 in) thick.