Granado bomb vessel, launched in 1742. It has two mortars inline. National Maritime Museum, London.
‘Erebus’ and the ‘Terror’ in New Zealand, August 1841, by John Wilson Carmichael.
In the 1690s an entirely new class of warship caused consternation and a crisis of conscience to the English ruling classes. The offender was the “bomb ketch”, a vessel copied from the French. Bomb ketches were small, shallow draft ships, able to get close inshore. They were armed with a dastardly weapon, a large bore mortar, which threw an explosive bomb far up in the air so that it cleared the walls of waterside cities or harbours and exploded when it struck the ground, damaging property and killing soldiers and civilians alike. The British used them thus to bombard St Malo, Le Havre, Dieppe and Dunkirk. John Evelyn, the diarist, wrote that the Navy should be employed to protect British shipping not “Spending their time bombing and ruining a few paltry little towns . . . a hostility totally averse to humanity and especially to Christianity”, however the bomb vessels, Christian or otherwise, continued to be developed and used. They fought the French off Gibraltar, where in a flat calm they engaged and severely damaged some French ships of the line, and at Toulon, where the fire from English and Dutch “bombs” destroyed several ships in harbour and caused the French to panic and scuttle the remains of their battle fleet at its moorings. This was a particularly significant action in that the Allies had landed observers ashore to watch the fall of shot and signal corrections to the gun layers afloat. This practice became frequently used when bomb vessels were employed, and a special force of observers were trained and retained by the Ordinance Board to undertake these duties. They would go to sea in tenders, one of which was attached to each bomb vessel to accommodate them and to carry spare ammunition.
These useful vessels remained in service throughout the eighteenth and the first part of the nineteenth centuries. A typical action was at Copenhagen in 1807. Britain was attempting to prevent the Danish fleet falling into French hands, following the agreement between Napoleon and the Tsar at Tilsit. The Danes refused to hand their ships to Britain “for safe keeping” and a fleet under Admiral Gambier accompanied by a force of 25,000 soldiers set out to compel them to do so. Thunder, Vesuvius, Aetna and Zebra, all bomb ketches, bombarded the fortress of Trekroner, in the approaches to Copenhagen, while troops and artillery advanced on land. After a pause for negotiation, which proved fruitless, fire was opened on the city itself as well as the fortress. This time, the efforts of the bomb vessels were supported by land based cannon and mortars. A huge timber yard was set on fire and eventually the city itself was in flames. The Danes capitulated and their fleet was captured or destroyed. In subsequent skirmishing Thunder was in action against Danish oared gun boats which she successfully drove off by using her mortar to fire “air bursting” bombs which exploded over their target, showering it with lead balls.
During the Crimean War (1854-6) both French and British navies employed a number of bomb vessels and also developed a class of barges fitted with heavy mortars to engage targets on land. The first of these barges built in Britain had names, but subsequently they were only given numbers, a practice to be continued for the small monitors built many years later.
The bomb vessels of the nineteenth century shared many characteristics with their early forebears and indeed with the bombardment vessels of the two twentieth century world wars. Their primary role was shore bombardment and to achieve this they needed very heavy weapons which could out range or out shoot shore based artillery. Most of these ships had two mortars, one 13 inch and one 10 inch. To support the recoil of these enormous weapons vessels had to be extremely heavily built, and to fire at all accurately they had to be very stable. This, together with the need for shallow draft, so as to get close to the enemy fortifications, resulted in ships with a very broad beam and poor sailing qualities. Their appetite for heavy ammunition meant that they required capacious tenders. Early ships had indeed been “bomb ketches” – ketch rigged vessels with a fore and aft mainsail on a mast set well back in the hull – the mortar fired forwards, over the bows. They must have been horrors to handle. Later “bombs” were “ship rigged” with three masts, but they remained slow and unhandy at sea. When the ships were not required for their main purpose the mortars would be removed and replaced with conventional armament so that they could be rated as sloops and undertake convoy duties, although in this role they must sometimes have had problems keeping up with their charges. Conversely in war time merchant vessels were often requisitioned and converted into makeshift “bombs”. A very suitable occupation for naval bomb vessels in peace time was polar exploration, for which their very strong build and shallow draft made them ideal. Erebus and Terror – names which we will encounter again later – made an epic voyage to the Antarctic in 1841 and 1842 which included being severely damaged by ice, battered by gales, threatened by enormous ice-bergs and finally a near fatal collision. No ships except bomb vessels would have survived such hazards.
The adventures of these wooden sailing vessels may seem far removed from those of the monitors of the twentieth century, but in fact they are closely related. Both were small shallow draft ships, slow and unhandy but mounting massive fire power. Both were unsuitable for fighting other ships at sea but could be devastatingly effective against targets on land or enemy ships in harbour. Above all they both needed to work in close co-operation with land forces. This involved communicating effectively with observers on land (or later in the air), understanding the military situation and bringing down their massive fire power on the right spot at the right moment. At the same time they had to be relatively cheap ships with small crews, since they would be required to operate at great risk to themselves close under the guns of enemy fortifications, where it would be foolish to hazard a valuable ship of the line.