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On Monitors (Royal Navy internal memorandum)


The Monitor type has a number of advantages to it, both designed and accidental, and a number of commensurate disadvantages.

The first of the benefits is that the ship type is very low to the water, meaning that aside from those sections which rise above the normal freeboard it is very hard to hit from a ship that is rolling and tossing itself. The difficulty here is not the problem of aiming a gun for bearing, which is a relatively simple problem at moderate range, but that of getting the gun on for elevation - the roll of a ship may include several degrees of arc, and a problem already difficult when firing upon a high-sided ship of the line is much harder when the target vessel shows only a foot or so of freeboard.
However, this comes at a considerable cost - to whit, the ship is extremely unseaworthy. Not only is there green water across the deck in all but the most mild of seas, but the reserve bouyancy is measured in tonnes rather than in hundreds of tonnes - if the monitor is pierced enough to admit the sea, then it is quite likely the vessel will go to the bottom in short order unless the crew is very prompt. (In particular the Monitor will be very at risk when high on coal, such as at the beginning of a sea voyage.) Fighting a ship of this type in more than a moderate sea may be seen as nearly impossible.

The second is that the gun may be trained on either broadside, allowing a single mighty gun to do the work of two guns - one on each broadside - of another kind of vessel.
This is also its own disadvantage - a Monitor is vulnerable to attack on the side the turret is not facing - and brings questions of mechanical reliability. The recommendation is that any future Monitor-type ship constructed by or for the Admiralty should include a minimum of two turrets for redundancy and to fight both sides at once.

Third is that, as the Monitor is a pure steam vessel, it has no rigging and may use her turrets for true all-around fire. This carries with it severe penalties on range which need not be commented upon in any great depth.

Fourth is that the high turret, as the only vulnerable section of the ship, may be heavily armoured enough to resist even the greatest guns of the enemy.
This supposes that a shot-proof ship is possible, and the moment that a gun is developed which may pierce the turret then a Monitor is highly vulnerable - as the whole of the ship above the waterline is 'vital' and can cause the ship to sink or be disabled if pierced, while for another ship there are areas which can endure a battering or piercing without immediately rendering the vessel unfightable.

In addition to these points, it has been mooted that the low position of the turret in a classical monitor means that the vessel lacks 'command'. This is more a matter of the freeboard than anything, and indeed a low position for the guns may be preferable for a ship intended to fight at short to moderate range...