Ratings of the Royal Navy have used cutlasses, short, wide bladed swords, since the early 18th century. These were originally of non-uniform design but the 1804 Pattern, the first Navy-issue standard cutlass, was introduced at the start of the 19th century. This was a bluntish weapon that was perhaps intended for cutting away canvas and ropes rather than as a thrusting combat weapon. The 1845 Pattern cutlass introduced a bowl-style hand guard which provided greater protection, with a longer and more curved blade. Its sharper point made it more useful for thrusting attacks, which were now emphasised in the drill manual. The 1845 Pattern was modified several times including shortening and straightening the blades, which weakened them. The 1889 Pattern had a straight, spear-pointed blade with a hilt that curved outwards to catch and redirect an opponent's sword point. The 1900 Pattern, the last navy-issue cutlass, was similar to its predecessor with the introduction of a fuller and a hilt insert that cushioned the user's little finger. The cutlass was withdrawn from service in 1936 but remains in use for ceremonial purposes. It is thought that it was last used in combat in 1900 during the Boxer Rebellion.

In addition to the cutlass the Royal Navy designed and issued cutlass-style bayonets for some of its mid-19th-century rifles. The first of these was introduced in 1859 for the Pattern 1853 Enfield. This was the first rifle to be issued to the navy, who had previously used muskets with standard British Army issue bayonets. The 1859 Enfield Cutlass Bayonet could be used either as a handheld weapon or mounted to the rifle. It proved less than ideal in both roles, its hilt not providing sufficient protection for the hand and its weight unbalancing the rifle. The 1859 Pattern bayonet remained in use when the rifle was converted to the Snider–Enfield. The introduction of the Martini-Henry rifle saw a new 1871 Pattern cutlass bayonet introduced. Though some new weapons were manufactured, many were made by cutting down the 1859 Pattern which weakened the blades. When the navy adopted the Lee–Metford rifle in 1888 it did not design its own cutlass bayonet and used the standard army-issue pattern.

Background The cutlass is a short sword with a wide single-edged blade that is often curved. In the Royal Navy it was a sword purchased by the government and issued to ratings, the enlisted men. Officers carried privately purchased long swords and midshipmen dirks. Seaborne soldiers of the Royal Marines were not issued cutlasses and instead carried bayonets for their longarms. When carrying out a boarding action the first wave of sailors would often be issued a cutlass and pistol for offensive action while the second wave were armed with more defensive weapons such as the boarding pike.

The cutlass may have had its origins in the hanger, a short curved sword that was used by the Royal Navy in the 17th century. The term "cutlass" was never used by the navy as the designation for an individual weapon pattern; the official terms used were "Sword for Sea Service" or "Sword, Naval". However, the weapon was commonly referred to as such in unofficial and official situations, for example the navy drill manual describes "cutlass" exercises.

Early cutlasses From the beginning of the 18th century the cutlass began to be adopted as the melee weapon for naval ratings. The Board of Ordnance placed orders for quantities of the weapons but these do not seem to have been from a set pattern with different manufacturers providing their own styles of sword.

Surviving weapons from this period have blades measuring in length with a fuller groove on the back edge. The hilts are sometimes brass and sometimes steel. Brass was more corrosion resistant and cheaper than steel but heavier and more easily damaged. Many surviving brass hilts show evidence of damage to the knuckle guard or quillon (cross guard at the back of the grip). By the middle of the century advances in steel-making, such as the use of drop forging, had reduced the cost of the material and the Royal Navy adopted the steel hilt. In naval service the hilt was often painted black for corrosion protection.

From around the middle of the century the Board of Ordnance favoured the "double disc" or "figure of eight" cutlass hilt. This most likely originated with weapons supplied by Thomas Hollier of Whitechapel who sold 1,000 cutlasses to the board in 1726. The hilt featured a circle of metal above the hand as a crossguard and another circle as a knuckle guard. Although antler had earlier been favoured as a material for the grip the board switched to a plain tubular-shaped steel grip, which was cheaper but also slippery in wet conditions.

Navy pattern cutlasses 1804 Pattern The Board of Ordnance established its first standard pattern of cutlass in 1804, placing an order for 10,000 "Swords for Sea Service" on 30 May. By this time ships-of-the-line were carrying hundreds of cutlasses each. The blade of the 1804 Pattern cutlass was almost straight and had no fuller. It measured in length and in width. Many surviving examples have a bluntish point which, with the blade's flat profile giving it poor stiffness, made it a poor thrusting weapon. This was either due to cost limitations or as the weapon was intended to be used for cutting with the edge. One intended use might have been for cutting away canvas and ropes, for which the heavy weight of the blade was advantageous.

The 1804 Pattern cutlass had a double disc guard though, unlike earlier cutlasses, the quillon was a relatively small roll of steel. The smooth tubular grip was replaced by one of cast iron, shaped to fit the hand and with grooves (usually 18 circumferential and six longitudinal) to improve grip. Like many of the 18th-century cutlasses there was no pommel where the guard met the grip. A slot in the guard allowed for the use of a sword knot, possibly because the Board of Ordnance was more familiar with British Army swords, which it also supplied, on which these features were provided. The navy does not appear to have issued sword knots as standard but there is some contemporary evidence that the slot was used with rope to attach the sword to the user's wrist.

The cutlass was provided with a brown leather scabbard, with a brass chape. The scabbard had no locket around the top and was connected to the user's belt by means of a frog hook straight through the leather. This was a relatively weak fixing and few hooks remain on surviving scabbards. Aside from government markings the 1804 Pattern cutlass is similar to, and sometimes confused with, early American cutlasses and the 1814 Pattern Norwegian cutlass.

1845 Pattern After the end of the Napoleonic Wars in 1815 the Royal Navy reduced in size from 145,000 men to 19,000. Despite this drop in the requirement for new cutlasses the Board of Ordnance held trials of six new designs in 1841. In the following year The Admiralty accepted the design proposed by George Lovell, the inspector of small arms. The 1845 Pattern cutlass appears to have been based on Lovell's designs. It is possible that this pattern entered service earlier than 1845 but a fire at the Tower of London storehouse has clouded the issue. 1845 is the first year that saw significant quantities of the cutlass issued.

The 1845 Pattern was significantly different from the 1804 Pattern. The blade, at , was the longest of any pattern of cutlass to be issued and was significantly more curved. The knuckle-guard was a simple steel bowl, providing greater protection than the double disc design, the outside of which curved outwards for additional strength (a feature retained in later patterns). The hilt had no quillon but retained the slit for a sword knot. It is possible that the guard was modelled on that of the 1821 Pattern Heavy Cavalry Sword, though this retained the quillon and lacked the outwards curve.

The 1845 Pattern retained the cast-iron grip but it was simplified with no longitudinal grooves and only 12 circumferential grooves. The grip was also less ergonomically shaped than the 1804 Pattern, possibly for cost reasons. The 1845 Pattern also introduced a small pommel at the base of the hilt, which was referred to as a burr. The scabbard was similar to the 1804 Pattern, with the same lack of locket which again often allowed the frog hook to pull out from the leather. The 1845 Pattern featured an acute point, making it more useful than its predecessor for thrusting which was now emphasised in the navy's drill manuals.

Modifications The 1845 Pattern was subject to many minor modifications, though the official records of these have been lost. These would have come within the remit of the War Department (and its successor the War Office), which took over responsibility for the procurement of naval weapons, including cutlasses, in 1854, shortly before the Board of Ordnance was disbanded.

A modification introduced around 1859 reduced the distance between the grip and inside face of the knuckle guard from to , narrowed the width of the guard where it met the pommel and inserted a washer between the guard and the grip. The top edge of the guard was also turned out slightly, towards the blade. At the same time the blade was shortened to and reduced slightly in width.

In the 1870s the blades were again shortened, this time to . The same decade a second round of modifications straightened the blades. The straightened blades were not initially re-heat treated, which left them weaker and liable to bend. Following complaints some were re-treated, these being marked with an "R". In 1887 the blades were shortened further.

1889 Pattern

Perhaps because stocks of the 1845 Pattern cutlass were running low, preventing further modification, a new pattern was introduced in 1889. The 1889 Pattern cutlass was straight, with a spear point. The bowl-hilt of the weapon was modelled on the 1882 Pattern Cavalry Sword. The grip was formed of cast iron and almost cylindrical. The 1889 Pattern included perhaps the most innovative feature of any Royal Navy cutlass. The edge of the guard was rolled outwards, adding strength to the guard and also acting as a stop rib which could catch an opponent's sword point and deflect it away from the user. A mix of bright steel and black-painted sword guards seem to have been used. It is likely that ceremonial weapons were kept in bright steel and service weapons were painted, either before being issued or on an ad hoc basis on ships. The scabbard of the 1889 Pattern cutlass was in black leather with two steel mounts and, for the first time in a Royal Navy pattern, featured a locket.

1900 Pattern

The final cutlass approved for naval use was the 1900 Pattern. This retained the straight blade of the 1889 Pattern, but introduced a fuller running one-third of the blade length. The bowl-type hilt with upturned rim was also retained, though a concave insert was added to the inside where the guard joins the pommel. This helped to cushion the user's little finger and was derived from the 1890 Pattern Cavalry Sword. As with the 1889 Pattern grips survive in both bright steel and black paint. The grip of the 1900 Pattern cutlass was more rectangular in section than its predecessor and had a knurled leather cover. The scabbard was identical to that used for the 1889 Pattern.