Hemmema



A hemmema was a type of warship built for the Swedish archipelago fleet in the late 18th and early 19th centuries. It was developed for warfare in the Archipelago Sea and along the coasts of Svealand and Finland against the Russian navy. The hemmema was designed by the prolific naval architect Fredrik Henrik af Chapman for use in an area of mostly shallow waters and groups of islands and islets that extend from Stockholm all the way to the Gulf of Finland.

Background
In the early 18th century, the establishment of Russian naval power in the Baltic challenged the interests of Sweden, at the time one of the major powers in the Baltic. The Swedish empire at the time included territory in Northern Germany, all of modern Finland and most of the Baltic states, a dominion held together by the Baltic sea routes. Russian Tsar Peter the Great had established a new capital and naval base in Saint Petersburg in 1703. During the Great Northern War Sweden lost its Baltic state territories, and experienced destructive Russian raiding in Finland and along the chain of islands and archipelagos that stretched all the way from the Gulf of Finland to the capital of Stockholm. The traumatic experience led to the establishment of inshore flotillas of shallow-draft vessels. The first of these consisted mainly of smaller versions of the traditional Mediterranean warship, the galleys. Most of these more akin to galiots and were complemented with gun prams. The disastrous war against Russia 1741-43 and the minor involvement in Prussia in the Seven Years' War 1757-62 showed the need for further expansion and development of the inshore flotillas with more specialized vessels.

Traditional galleys were effective as troop transports for amphibious operations, but were severely under-gunned, especially in relation to their large crews; a galley with a 250-man crew, most of whom were rowers, would typically be armed with only one 24-pounder cannon and two 6-pounders, all in the bow. However, they were undecked and lacked adequate shelter for the rower-soldiers, great numbers of which succumbed to illness in the war of 1741-43. The Swedish military invested considerable resources into the establishment of the "archipelago fleet" (skärgårdsflottan), a separate branch of the armed forced that organizationally belonged to the army. In 1756, it was even officially designated Arméns flotta, "Navy of the Army", though it was in many ways a highly independent organization that attracted a social and cultural elite and enjoyed the protection of Gustav III after his 1772 coup that empowered him as an absolute monarch.

Several new ships were designed by the naval architect Fredrik Henrik af Chapman to bolster the hitting-power of the new Swedish arm, to provide it with better naval defense and greater fire support capabilities during amphibious operations. The result was four new vessels that combined the maneuverability of oar-powered galleys with the superior rigs and decent living conditions of sailing ships: the udema, pojama, turuma and hemmema, named after the Finnish regions of Uusimaa ("Uudenmaan" in genitive form), Pohjanmaa, Turunmaa and Hämeenmaa (Tavastia). All four have been referred to as skärgårdsfregatter, "archipelago frigates", in Swedish and English historical literature, though the smaller udema and pojama are also described as "archipelago corvettes" originally. The name "hemmema" has been carried on (in its more modern variant) as a traditional vessel name in the Finnish navy, with several ships named after the type.

Design
Along with the turuma, the hemmema was the type of specialized archipelago warship that closest fit the description of "archipelago frigate", showing considerable similarities with small ocean-going frigates. The first hemmema, the Oden, was completed in 1764. It was c. 33 m (110 ft) long and 8.5 m (27.5 ft) wide with a draft of 3 m (10 ft). It had a low hull with no forecastle, only a low quarterdeck and no poop deck. There were three masts that were initially rigged with lateen sails, like a galley, by this was later replaced with a more conventional square-sail frigate rig. The early design could be rowed with 14 pairs of oars with four men per oar. The rowers plied their oars from the gun deck through oarports placed between the gunports, much nearer to the waterline than the turuma, where the oarsmen sat on the weather deck above the guns. The oarports were placed on a rectangular outrigger that was designed to improve their leverage. Despite this, hemmemas performed poorly when rowed and were difficult in contrary winds. They were slower than ordinary sailing ships, but were better sailers than galleys.

During the Russian war of 1788-1790, three hemmemas of a new design were built. They were considerably larger, 44.5 m (146 ft) by 11 m (36 ft), and the number of oars were increased to 20 pairs. It also carried among the heaviest broadsides in the entire navy. The artillery officer Carl Fredrik Achling had cooperated with Chapman to bring up the main armament to 22 36-pounders and two 12-pounders, which increased the draft by about 30 cm (1 ft). The heavier armament was possible by the addition of diagonal bracers to reinforce the hull, and allowing the later hemmemas to carry guns that more powerful than even the largest sailing frigates of the high seas navy. Due to their considerable firepower and relative size, they have been described as "super archipelago frigates" by naval historian Jan Glete.

The hemmema's design was very similar to the turuma. The primary difference was that hemmemas were rowed from the gundeck, providing the oarsmen with better leverage by placing them closer to the waterline. The later hemmemas were also considerably larger, more heavily armed and of a more robust construction. Glete has gone as describing them as variations on the same type, especially when considering the pre-war designs.

The concept of hybrid frigates with oar propulsion capabilities was not new. Small "galleasses" had been built for the English navy as early as the mid-16th century, and the British navy had equipped the equivalent of sixth rates with oar ports on or below the gundeck as early as the 1660s. "Shebecks", Baltic variations on the Mediterranean xebecs, had been introduced in the Russian navy for inshore duties during the 18th century. Both of these have been suggested as possible inspirations for af Chapman's new designs.

Service
Hemmemas served in the Finnish squadrons during the war of 1788-1790. They were used to support amphibious operations and to conduct raids on the Russian archipelago fleet, while at the same time acting as a sea-borne flank support for the Swedish army on the Finnish mainland. Hemmemas fought in the first and second battles of Svensksund. In the first in August 1789, one hemmema complemented the similar turumas, and at the second battle in July 1790, two hemmemas made up the defensive center and provided a considerable percentage of the total firepower.

Additional hemmemas were being constructed at the fortress of Sveaborg when it was captured by the Russians in 1808. Shortly afterward, the Russians built their own versions with 32 guns that were 43.8 m (143.75 ft) long and 10.8 m (35.5 ft) wide, and one was built for the Russian Baltic fleet as late as 1823. Two more were built in Sweden in 1809 (with only 10 pairs of oars), and there were plans to convert one of these to a paddlewheel steam battery for coastal defense, though the idea was eventually scrapped.

Like the other specialized archipelago vessels, the hemmema had only limited advantages. While it had superior firepower, its sailing qualities were mediocre and they were quite slow under oars. Hemmemas had the potential to be an effective weapon against galleys, matching their forward firepower and severely outgunning them with its broadside armament. Inside an enemy galley formation, it could wreak considerable havoc, but such a maneuver was never achieved in an actual battle, leaving that tactical role untested.

Ships
Nine hemmemas were built altogether, six of them for the Swedish archipelago fleet. Another three were built for the Russian fleet, two in 1809 and one as late as 1823. Ships with known names are listed below with launch year in parenthesis.


 * Oden (1764)
 * Hjalmar (1790)
 * Starkotter (1790)
 * Styrbjörn (1790) — She participated in the "Vyborg gauntlet" where she led the archipelago fleet in the successful break-out of the Russian blockade and formed part of the center at the second battle of Svensksund. She was named after the Viking king Styrbjörn the Strong. Styrbjörn and her sistership Hjalmar were in winter storage at Sveaborg in May 1808 when the fortress was surrendered over to the Russians. Her Russian service was however short. On the night of 17–18 August 1808, the Swedish captain Otto Gustaf Nordenskjöld and lieutenant A. Dreijer launched a surprise attack with 24 launches and sloops and managed to cut out Styrbjörn and the smaller yacht Aglae. The ships began sailing to friendly ports but Styrbjörn  ran aground on a skerry after a Russian attack. Her crew decided to abandon her and set her ablaze to prevent capture and she was completely destroyed when the fire reached the gunpowder magazine.
 * Birger Jarl (1809)
 * Erik Segersäll (1809)