 = <unk> = 
 
 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 . 
 The hemmema replaced the galleys that had made up the core of the Swedish archipelago fleets until the mid @-@ 18th century . Compared to galleys , the hemmema had a deeper draft and was slower under oars , but offered superior accommodation for the crew , carried more stores , was more <unk> and had roughly ten times as many heavy guns . It could be propelled by either sails or oars but was still smaller and more <unk> than most sailing warships , which made it suitable for operations in confined waters . 
 Between 1764 and 1809 , Sweden built six hemmemas . The hemmema became the largest and most heavily armed vessel in the archipelago fleet and served in the Russo @-@ Swedish War of 1788 – 90 . Oden , the first hemmema , was relatively small and very similar to a turuma , a different type of " archipelago frigate " . Russia built six hemmemas based on the Swedish design between 1808 and 1823 after capturing three of the Swedish vessels at the surrender of Sveaborg in 1808 . The later versions , both Swedish and Russian , were much larger and much more heavily armed than Oden . 
 
 = = Background = = 
 
 Russian Tsar Peter the Great had established a new capital and powerful naval base in Saint Petersburg in 1703 . Russian naval power in the Baltic grew to challenge the interests of Sweden , the other leading power in the Baltic . Swedish holdings at that time included territory in Northern Germany , all of modern Finland and most of the Baltic states , a dominion depending on , and connected by , the Baltic Sea trade routes . During the Great Northern War ( 1700 – 1721 ) , Sweden lost all its territories in the Baltic states and suffered Russian raids in Finland and along the chain of islands and <unk> stretching from the Gulf of Finland to Stockholm . The Swedes began to deploy inshore flotillas of shallow @-@ draft vessels , beginning with smaller versions of the traditional Mediterranean galleys . Most of these new vessels were more akin to <unk> and were complemented with gun prams . The disastrous war with Russia ( 1741 – 43 ) and the minor involvement against Prussia in the Seven Years ' War ( 1757 – 62 ) showed the need for further expansion and development of the inshore flotillas with more specialized vessels . 
 <unk> were effective as troop transports for amphibious operations , but were severely under @-@ <unk> , especially in relation to their large crews ; a galley with a 250 @-@ man crew , most of whom were rowers , would typically carry only one 24 @-@ pounder cannon and two 6 @-@ pounders , all in the bow . The galleys also lacked decks and adequate shelter for the rower @-@ soldiers , many of whom succumbed to illness as a result of exposure during the war of 1741 – 43 . 
 
 = = = Archipelago fleet = = = 
 
 After the Russian victory against Sweden in 1743 , the Swedes established a commission to identify weaknesses in the eastern defenses . In 1747 , the commission concluded that the fortifications in southeastern Finland needed to be improved and expanded , and that Sweden needed to build a strong coastal navy . Augustin Ehrensvärd ( 1710 – 72 ) , an artillery officer , was the driving force behind these changes . The committee based many of its conclusions and decisions on his ideas . In 1756 , Sweden established the archipelago fleet with the official name <unk> <unk> ( " fleet of the army " ) under the command of the army department , <unk> , with Ehrensvärd as supreme commander . For two decades , the struggle for power between the Hats and the <unk> , the dominant political factions at the time , and rivalries between army and navy brought about changes to the archipelago fleet . The parliamentary victory of the Hats in the <unk> in 1769 – 70 and the coup d <unk> by King Gustav III in 1772 secured the archipelago fleet 's status as an independent branch of the army . Starting in 1770 , the archipelago fleet merged with the Finnish Squadron ( <unk> <unk> ) based at Sveaborg . In 1777 , it incorporated the Swedish Squadron ( <unk> <unk> ) , the galley fleet based at Stockholm . The Swedish armed forces invested considerable resources in the new army branch and made it a professional , independent organization . The archipelago fleet attracted members of the social and cultural elite who enjoyed the protection and patronage of King Gustav III , who had established himself as an absolute monarch in the 1772 coup . 
 After the poor performance of galleys in Russo – Swedish war of 1741 – 43 and the <unk> War ( 1757 – 62 ) , development of replacements became <unk> . During the <unk> War , trials had been made with " gun prams " ( <unk> ) , heavily armed , oar @-@ driven , flat @-@ bottomed barges with a shallow draft that carried guns in broadside arrangements . The prams carried more guns than the galleys , but proved far too slow to be effective . Augustin Ehrensvärd argued for new archipelago vessels that combined firepower , maneuverability , <unk> , and decent crew accommodations . He began a successful collaboration with <unk> Fredrik Henrik Chapman ( <unk> " <unk> Chapman " in 1772 ) , and together they developed five new vessels : a gunboat with a 12 @-@ pounder gun and a schooner rigging , as well as four types of " archipelago frigates " ( <unk> ) : the smaller <unk> and <unk> , and the larger turuma and hemmema . All four types have been called <unk> ( archipelago frigates ) in Swedish and English historical literature , though some authors have called the <unk> and <unk> " archipelago <unk> " . Chapman specifically designed the archipelago frigates for service off the south coast of Finland and named them after the Finnish provinces of <unk> , <unk> ( <unk> ) , <unk> ( <unk> ) , and Hämeenmaa ( <unk> ) . 
 
 = = Development = = 
 
 The concept of small sailing frigates with a complementary set of oars ( or " <unk> " ) was not new . The English Tudor navy had used small " <unk> " in the mid @-@ 16th century . In the 1660s its successor , the Royal Navy , equipped the equivalent of sixth @-@ rates with oar ports on or below the <unk> . During the 18th century the Russian Navy introduced " <unk> " , Baltic variants on the Mediterranean <unk> , for inshore duties . The <unk> were good <unk> , could be rowed if necessary and had more guns and greater stores than galleys ; they were also less expensive to maintain . The Russian designs influenced Chapman and the Swedish naval commanders . Consequently , Chapman 's designs for new ships were <unk> on those principles , but with adaptations to archipelago warfare . 
 Chapman 's archipelago frigates provided better protection for their crew than the galleys they replaced , and up to three times the capacity for stores and provisions . They could operate in the narrow , shallow waters around <unk> in all <unk> and in open water in all but the worst storms . They had a deeper draft than galleys , but considerably shallower draft than traditional sailing warships . The new ship types also increased the archipelago fleet 's firepower , provided it with better defensive capabilities , and made possible more efficient fire support in amphibious operations . 
 
 = = Design and construction = = 
 
 Of the new designs , <unk> and hemmemas best fit the description of " archipelago frigate " because of their similarities to small ocean @-@ going frigates . The first hemmema , the Oden , was completed in 1764 . It was c . 33 m ( 108 @.@ 2 ft ) long and 8 @.@ 2 m ( 26 @.@ 8 ft ) wide with a draft of 2 @.@ 8 m ( 9 @.@ 25 ft ) . It had a low hull with no forecastle , only a low quarterdeck , and no <unk> deck . It had three masts that were initially rigged with <unk> sails , like a galley . The navy later replaced the <unk> rigs with a more conventional square @-@ sail frigate rig . The early design provided for 14 pairs of oars with four men per oar . The rowers plied their oars from the gun deck through oar ports positioned between the gunports , close to the waterline , which gave the rowers better leverage . The oars were also placed on a rectangular <unk> , designed to further improve the leverage . Even so , hemmemas performed poorly when rowed and were difficult in contrary winds . They were slower than ordinary sailing ships , but sailed better than galleys . 
 During the Russian war of 1788 – 1790 , Sweden built three hemmemas of a new design . They were considerably larger , 44 @.@ 5 by 11 m ( 146 by 36 ft ) , and the number of oars were increased to 20 pairs . They also had some of the heaviest broadsides , even when compared with the much larger frigates of the high seas navy . The artillery officer Carl Fredrik <unk> had cooperated with Chapman to increase the main armament to twenty @-@ two 36 @-@ pounders and two 12 @-@ pounders , which increased the draft by about 30 cm ( 1 ft ) . The addition of diagonal <unk> to reinforce the hull allowed the later hemmemas to carry guns more powerful even than those on the largest sailing frigates of the high seas navy . Due to their considerable firepower and relative size , naval historian Jan <unk> has described the hemmemas as " super archipelago frigates " . 
 The hemmema 's design was very similar to that of the turuma . The primary difference was that the turuma 's oarsmen sat on the weather deck above the guns , whereas the hemmema 's oarsmen sat on the <unk> . The later hemmemas were considerably larger , more heavily armed , and of a more robust construction . <unk> has described them as variations on the same type , especially when considering the pre @-@ war designs . 
 
 = = Service = = 
 
 <unk> served in the Finnish squadrons during the war of 1788 – 1790 . They supported amphibious operations and conducted raids on the Russian archipelago fleet , while at the same time acting as sea @-@ borne flank support for the Swedish army on the Finnish mainland . <unk> fought in the first and second battles of <unk> . During the first battle in 1789 , one hemmema complemented the similar <unk> , and in the second battle in July 1790 , two hemmemas made up the defensive center and provided a considerable percentage of the firepower . 
 The Swedes were building three additional hemmemas at the shipyards within the fortress of Sveaborg when it was surrendered to the Russians in 1808 , and all three were incorporated in the Russian Navy . Shortly afterward , the Russian Navy built its own 32 @-@ gun versions , with the final vessel launched as late as 1823 . Two more were built in Sweden in 1809 , Birger Jarl and Erik Segersäll . Birger Jarl sank in an accident in 1813 and Erik Segersäll was planned for conversion as a <unk> steam battery for coastal defense , though the idea was eventually abandoned and the ship scrapped in 1826 . 
 Like the other specialized archipelago vessels , the hemmema had specific strengths and weaknesses . Although it had superior firepower relative to galleys , its sailing qualities were somewhat mediocre and while highly <unk> under oars , it was still difficult to propel while rowed . A hemmema had the potential to be an effective weapon against galleys , matching their forward firepower and severely <unk> them with its broadside armament . Inside an enemy galley formation , it could <unk> considerable <unk> , but such a maneuver was never achieved in an actual battle , leaving that tactical role <unk> . 
 
 = = Ships = = 
 
 A total of twelve hemmemas were built , six of them for the Swedish archipelago fleet and six for the Russian Navy . Details of individual vessels are listed below . The Swedish hemmemas were all built to the same specifications , except for the early design Oden , and Birger Jarl and Erik Segersäll carried heavier armament than the others . <unk> and <unk> list Oden as a turuma rebuilt as a hemmema in 1784 , though Oscar <unk> and Lars @-@ Otto Berg do not . The Russian vessels were built between 1808 and 1823 and have been described by <unk> and <unk> as <unk> @-@ class " rowing frigates " . 
 Under the Finnish form " Hämeenmaa " , the name of the ship type was later carried on to several vessels of the 20th century Finnish Navy . 
 
 