Metal Parts

G. Shifting trucks.

H. Training trucks, both with journals, and eccentric axles.

Tippecanoe Class MonitorTippecanoe Class Monitor

Above: A longitudal section of a monitor of the Tippecanoe class showing the wood and iron construction. Below left: Plan view.

Centre: The machinery of the USS Monitor, designed by Ericsson.

Right: Stern elevation of the Tippecanoe class, showing the cutup of the armoured raft and the large propeller.

Tom Brittain © Profile Publications Limited

Uss Catskill MonitorIronclad Monitor Hatch

tammmmmmm ers' quarters

Pickups With Side Pipe StacksPlan And Elevation Engine Parts

monitors still tended to slide from side to side when running at low speeds.

The side armour on the raft was increased to 5in. A permanent smoke stack 18ft in height was installed which was armoured with eight 1 in plates to a height of 6ft. Ten vent pipes, 4ft high, combined with two blower engines to increase ventilation below decks.

As an indication of the ability of the monitors to absorb punishment from contemporary guns, the following is extracted from the captain's reports of the Passaic's participation in the attack on the forts in Charleston Harbour 5 April 1 863 :

Catskill Received 20 hits. No serious damage.

Montauk Received 14 hits. Aft starboard section of the side armourtorn loose. Nahant Received 36 hits. Turret dented and jammed, side armour loosened and broken in several places. Nantucket Received 51 hits. Turret dented making the 15in gunport stopper inoperable. Passaic Received 35 hits. Pilot house damaged. Brass turret track broken.

Patapsco Received 47 hits. No serious damage. Weehawken Received 53 hits. Deck pierced. Side armour shattered in a single place.

It was obvious that an ironclad could 'slug it out' with shore fortifications and survive, but in the long run the continuous two-way pounding would be more detrimental to the ironclad than the fortifications it was attacking.

Canonicus-Class Coastal Monitors

The nine ships of the Canonicus Class (sometimes referred to as Tecumseh Class) were a major design advance over the Passaic Class. This was the first class to incorporate the lessons of combat exper-enced in the Monitor - Virginia clash and the operation of the earlier monitors.

Although the Canonicus was built on the general planform of the Passaic there was a small increase in size, the former being 25ft longer and 200 tons heavier. Improvements included the mounting of two 15in Dahlgren guns with a more sophisticated recoil system replacing the hybrid arrangement on the Passaics, improved armour protection, a more efficient hull design, better ventilation and larger boilers. Four of the Canonicus Class were built in yards along the Ohio River.


A band of armour 5in thick and 1 5in high was added to the deck around the base of the turret to protect the turret from being jammed by a shot hitting it at its base. The turret itself carried only 10in of armour as against 11 in on the Passaics. However, the pilot house armour was increased to 10in. The raft retained the 5in armour of the Passaics but in addition two armour stringers, one on top the other just above the waterline, ran along the sides of the raft backing the armoured skirt. For a distance of about 70ft from the bow these belts were each 6in wide and 6-5in deep, for the rest of the run aft they were 4in wide. The deck armour was increased to 1 -5in.

Other Improvements

The hull was more efficient in design than the Passaics. Much of the 'deadwood' was cut away to improve the efficiency of the four-bladed 13ft diameter screw. These improvements and larger boilers enabled the larger Canonicus-C\ass ships to have a designed speed of 13 knots and a service speed of 8/9 knots while using the same horsepower engines as was installed in Monitor and the Passaics. A wider; lower, armoured smoke stack as compared to the Passaics was carried.

A total of three more powerful blowers were

A cross-section view of the original USS Monitor taken from John Ericsson's plans of the ship. The cross-hatched areas on the deck and sides are wood beams which the iron plate is laid on. The simple design to allow for fast construction time is quite evident. (U S N avy)

Uss Monitor Plan

A cross-section view of the original USS Monitor taken from John Ericsson's plans of the ship. The cross-hatched areas on the deck and sides are wood beams which the iron plate is laid on. The simple design to allow for fast construction time is quite evident. (U S N avy)

installed in an attempt to improve the ventilation problem. A half-platform deck was located under the living spaces and provided space for auxiliary machinery, piping and storage.

Dictatorand Puritan

These two ships were Ericsson's attempts at building a true oceangoing monitor. Dictator was 312ft long with an extreme beam of 50ft and drew 20-5ft. Both she and the Puritan retained the single turret concept. Although the Navy wanted two turrets on these ships to allow for more flexibility of topside design, greater broad-side weight and less reliance on the mechanical reliability of one turret. Ericsson argued that for a given size and displacement a single turret ship could always carry larger guns and thicker armour.

Dictator's raft became more an integral part of the hull. But she was found to be less buoyant than intended and therefore could only carry half her planned coal capacity. Although she handled well she could make only 12 of her designed 16 knots. She was driven by a single huge screw 21 -5ft in diameter. Because of her shortcomings Dictator was used only in the coast defence role. She was commissioned just five months prior to the end of the war.

Puritan was similar to Dictator in design and size being 340ft long, with extreme beam of 50ft and a draught of 20ft. She was to have a single turret equipped with two 20in guns, but she was never completed. Construction was suspended at the end of the war in 1865. In 1874 under the camouflage phrase of 'repairing' the Navy recommenced construction of Puritan. The result, however, was a completely new ship that wasn't completed until 1898.

1 Officers and crew at divine service on the afterdeck of USS Passaic, one of the ten Passaic Class, off Charleston, South Carolina during the Civil War. Note the iron vent stoppers laying open about the deck. (U S N avy)

2 A layout of the Canonicus Class monitor, USS Saugus. Forward to aft: The wardroom, officers cabins and offices; turret chamber; mess decks; coal bunkers; boilers; engine room.

Passaic Class MonitorAmerican Judah With Coal Bunker

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