British sea power and the Confederate steam rams

British sea power constrained other states' choices during the American Civil War. A government wishing to back the Confederacy would have needed British participation because only the Royal Navy could seriously challenge the blockade. Britain's long anti-slavery patrol effort made such support unattractive, despite discontent with the blockade in some quarters. The two steam rams built for Confederate use therefore entered Royal Navy service instead, giving the strategic argument a concrete procurement outcome.