monitor monitors group iron monitors built mid late 1860s designed supervision swedish born inventor built sweden generally monitors kept reserve majority year commissioned year ships foreign visit russia visits norway count foreign country personal union sweden remained swedish norwegian waters rest careers monitors ran aground salvaged repaired monitors reconstructed modern guns scrapped instead thought cost effective rebuild old ship surviving ships mobilized world war sold scrap design description ironclads designed meet need swedish norwegian navies small shallow draft armored ships capable defending coastal waters larger virginia early interest sweden new type warship ideal coastal defense duties parliamentary committee set earlier investigate state swedish navy concluded existing fleet obsolete new construction steam powered built iron designer builder monitor born sweden american citizen offered share design response sent lieutenant united_states study monitor design construction arrived july toured rolling mills gun visited different ironclads construction returned sweden having completed drawings monitor type ship supervision ships measured meters long overall beam meters draft meters displaced metric tons long tons ships divided main compartments watertight bulkheads time flying bridge later superstructure added ship gun turret funnel initially crew numbered officers men increased ships modified additional weapons built ship class somewhat larger half sisters meters long overall maximum beam meters ship drew meters displaced metric tons long tons fully loaded propulsion ships twin cylinder steam engines designed driving single bladed meter propeller engines powered fire tube boilers working pressure psi kpa cm2 engines produced total indicated horsepower gave monitors maximum speed knots mph calm waters ships carried tonnes long tons coal day steaming armament lead ship carried pair inch donated turret gun weighed approximately pounds fired pound solid shot pound explosive shell massive shells took minutes maximum muzzle velocity guns designated satisfied performance replaced guns later ships briefly armed pair millimeter guns rearmed millimeter rifled breech derived french design ship delivered equipped guns building weighed kilograms fired projectiles muzzle velocity maximum elevation range meters improved version developed 1870s fitted overhauled guns heavier kilograms higher muzzle velocity coupled increased elevation gave range meters monitors gradually received guns monitor received pair millimeter machine guns designed machine gun weighed kilograms rate fire rounds minute projectiles muzzle velocity maximum range meters guns replaced 1880s millimeter gun enlarged version original design kilogram gun rate fire rounds minute round muzzle velocity maximum range meters armor ships complete waterline armor belt wrought iron meters high millimeters thick armor consisted plates backed millimeters wood lower edge belt millimeters thick plates thick maximum thickness armored deck millimeters layers gun turret armor consisted layers iron totaling millimeters thickness monitors armor turret reinforced thickness millimeters face millimeters sides inside turret lined catch splinters base turret protected millimeter millimeters high turret roof millimeters thick conning tower positioned turret sides layers millimeters thick funnel protected layers armor total thickness millimeters half height construction service july later king inspected steam frigates norwegian monitor departed port visits later known august visited grand duke russia head imperial_russian_navy foreign visits swedish monitors generally monitors kept reserve majority year commissioned months summer fall named inventor kept pattern remained reserve afterward rearmed millimeter guns original guns monument ship reactivated sporadically reconstructed gun turret fixed place modified serve barbette new millimeter guns guns elevate firing arc millimeter quick firing guns added superstructure ship boilers replaced new cylindrical ones working pressure cm2 kpa psi reached knots mph sea trials early 1900s millimeter machine guns removed later millimeter guns added superstructure ship assigned local defense force sold swedish november company converted barge years final fate unknown later spelled laid reserve rearmed millimeter guns serial numbers laid ship ran aground sank july salvaged august managed proceed power repairs subsequent court martial ordered ship captain pay costs salvage repairs despite caused ship ground recommissioned placed reserve reconstructed received pair new millimeter guns given elevation limits ship received millimeter guns new boilers reactivated world war assigned local defense flotilla decommissioned sold following year new owner converted barge stockholm harbor commissioned monitors active mobilized world war received millimeter guns ship reconstructed time similar manner received millimeter quick firing guns taken class torpedo boats joined sister flotilla world war shared fate seven cruises finally placed reserve late funds requested rebuild refused decommissioned august advertised sale details fate unknown presumably sold scrapped built monitor type ship laid norwegian parliament authorized construction sweden cost norwegian armed pair steel millimeter armstrong rifled muzzle loading guns turret millimeter gun ship ran aground lightly damaged visited sweden occasion visiting sweden west coast ports early 1870s reconstructed turret converted barbette main guns replaced pair millimeter quick firing guns addition millimeter millimeter guns mounted superstructure millimeter hotchkiss barrel revolving guns spent career scrapped
John Ericsson-class monitor