 A hemmema ( from Finnish " Hämeenmaa " , <unk> ) was a type of warship built for the Swedish archipelago fleet and the Russian Baltic navy in the late 18th and early 19th centuries . The hemmema was initially developed for use against the Russian Navy in the Archipelago Sea and along the coasts of <unk> and Finland . It was designed by the prolific and innovative Swedish naval architect Fredrik Henrik <unk> Chapman ( 1721 – 1808 ) in collaboration with Augustin Ehrensvärd ( 1710 – 1772 ) , an artillery officer and later commander of the Swedish archipelago fleet . The hemmema was a specialized vessel for use in the shallow waters and narrow passages that surround the thousands of islands and <unk> extending from the Swedish capital of Stockholm into the Gulf of Finland . 
