Palmerston's War

In case of war with the United States, Admiral Alexander Milne, Commander of the RN's North American Station, planned to divide his 54 or so ships into five or six squadrons. 

One of those squadrons was to be a group of Ironclads meant to deal with American ports. 

So we've put together that squadron. As it happens by the spring of 1862 the RN had four Warrior Class Ironclads. We're putting them all in that squadron, plus the two decker wooden steamer Trafalgar and the three decker Duke of Wellington.

That's some serious firepower, people. Portland, Boston, New York....beware.

Palmerston's War The Royal Navy

In 1862 Britannia indeed ruled the waves.

The Royal Navy numbered over 300 ships.

In North American the navy had three important stations, an Halifax, Bermuda and Barbados. As war fears mounted, by 1862 54 ships were on the North American Station under the command of Admiral Alexander Milne. Halifax was well defended and had coal stores well provision by Canadian mines. Milne had carefully built up Bermuda stores.

In case of war Milne intended to keep 25 ships or so in the West Indies. Milne intended to break the Union blockade and then sweep down the east coast attacking ports. He had a detached squadron of Iron Clads for this purpose. If possible he would attack Washington, though this was unrealistic in 1862. From there Milne wanted to blockade the east coast at Chesapeake Bay, Delaware Bay, Sandy hook and Long Island Sound.

Aside from attacking Washington, there is no reason to think Milne and the North American Squadron could not have accomplished all he set out to do.