The Amur-class minelayers were the first purpose-built, ocean-going minelayers in the world. Both ships were constructed for the Imperial Russian Navy

Imperial Russian Navy

The Imperial Russian Navy refers to the Tsarist fleets prior to the February Revolution.-First Romanovs:Under Tsar Mikhail Feodorovich, construction of the first three-masted ship, actually built within Russia, was completed in 1636. It was built in Balakhna by Danish shipbuilders from Holstein...

 in the late 1890s. During the Russo-Japanese War

Russo-Japanese War

The Russo-Japanese War was "the first great war of the 20th century." It grew out of rival imperial ambitions of the Russian Empire and Japanese Empire over Manchuria and Korea...

 of 1904–05 they were assigned to the Pacific Fleet

Pacific Fleet

A number of countries currently have or previously had an Pacific Fleet in their navies.*United States Pacific Fleet*Pacific Fleet *Pacific Naval Force *British Pacific Fleet...

. Yenisei struck one of her own mines two days after the war began while laying a minefield and sank. One of Amurs minefields sank the Japanese pre-dreadnought battleships and . Amur was sunk by Japanese howitzer

Howitzer

A howitzer is a type of artillery piece characterized by a relatively short barrel and the use of comparatively small propellant charges to propel projectiles at relatively high trajectories, with a steep angle of descent...

s in December 1904 after the Japanese had gained control of the heights around Port Arthur. She was later salvaged

Marine salvage

Marine salvage is the process of rescuing a ship, its cargo, or other property from peril. Salvage encompasses rescue towing, refloating a sunken or grounded vessel, or patching or repairing a ship...

 and scrapped

Ship breaking

Ship breaking or ship demolition is a type of ship disposal involving the breaking up of ships for scrap recycling. Most ships have a lifespan of a few decades before there is so much wear that refitting and repair becomes uneconomical. Ship breaking allows materials from the ship, especially...

 by the Japanese.

Design and description

The Amur-class minelayers were designed to drop their mines

Naval mine

A naval mine is a self-contained explosive device placed in water to destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel...

 while at high speed and were given a pronounced, overhanging, stern that allowed the mines to be dropped behind the propeller

Propeller

A propeller is a type of fan that transmits power by converting rotational motion into thrust. A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, and a fluid is accelerated behind the blade. Propeller dynamics can be modeled by both Bernoulli's...

s through doors in the stern. Each door was served by a rail that led directly to the mine storage compartments.

The Amur-class ships were 300 feet (91.4 m) long at the waterline; they had a beam

Beam (nautical)

The beam of a ship is its width at the widest point. Generally speaking, the wider the beam of a ship , the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position...

 of 41 feet (12.5 m) and a draft

Draft (hull)

The draft of a ship's hull is the vertical distance between the waterline and the bottom of the hull , with the thickness of the hull included; in the case of not being included the draft outline would be obtained...

 of 18 feet (5.5 m). They had two pole masts and a ram

Naval ram

A naval ram was a weapon carried by varied types of ships, dating back to antiquity. The weapon consisted of an underwater prolongation of the bow of the ship to form an armoured beak, usually between six and twelve feet in length...

 bow.

The ships had two vertical triple expansion steam engines, each powering one propeller. Twelve Belleville water-tube boiler

Water-tube boiler

A water tube boiler is a type of boiler in which water circulates in tubes heated externally by the fire. Fuel is burned inside the furnace, creating hot gas which heats water in the steam-generating tubes...

s provided steam. The engines were designed to produce a total of 4700 ihp and gave the ship a top speed of 18 knots (9.8 m/s). They carried 400 long tons (406 MT) of coal that provided a range of 2000 nautical miles (3,704 km) at a speed of 10 knots.

The main armament of the Amur-class ships consisted of five 75 millimetres (3 in) Canet Pattern 1892 50-caliber

Caliber (artillery)

In artillery, caliber or calibredifference in British English and American English spelling is the internal diameter of a gun barrel, or by extension a relative measure of the length....

 guns. The gun fired 10.8 pounds (4.9 kg) shells to a range of about 8600 yards (7,864 m) at its maximum elevation of 21° with a muzzle velocity of 2700 ft/s (823 m/s). The rate of fire was between twelve and fifteen rounds per minute. The ships also mounted seven 47 millimetres (1.9 in) Hotchkiss gun

Hotchkiss gun

The Hotchkiss gun can refer to different products of the Hotchkiss arms company starting in the late 19th century. It usually refers to the 1.65-inch light mountain gun; there was also a 3-inch Hotchkiss gun...

s. They fired a 3.3 pounds (1.5 kg) shell at a muzzle velocity of 1476 ft/s (449.9 m/s) at a rate of 20 rounds per minute to a range of 2020 yards (1,847.1 m). The Amur-class ships mounted one 15 inches (381 mm) torpedo tube

Torpedo tube

A torpedo tube is a device for launching torpedoes. There are two main types of torpedo tube: underwater tubes fitted to submarines and some surface ships, and deck-mounted units installed aboard surface vessels...

 and carried 300 mines

Naval mine

A naval mine is a self-contained explosive device placed in water to destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel...

.

Service

Both ships, Amur and Yenisei, were built by the Baltic Works in Saint Petersburg

Saint Petersburg

Saint Petersburg is a city and a federal subject of Russia located on the Neva River at the head of the Gulf of Finland on the Baltic Sea...

. They were laid down in 1898 and completed the following year. They were assigned to the Pacific Fleet when the Russo-Japanese War began in 1904 and based in Port Arthur. Two days after the Japanese surprise attack

Battle of Port Arthur

The Battle of Port Arthur was the starting battle of the Russo-Japanese War...

 on Port Arthur on 8/9 February 1904, Yenisei was laying a minefield at Dalian Bay

Dalian Bay

Dalian Bay , is a bay on the southeast side of the Liaodong Peninsula of Northeast China, open to the Yellow Sea in the east. Downtown Dalian lies along the southern shore of the bay...

 when one mine broke loose and began floating towards the ship. While maneuvering to avoid the mine Yenisei accidentally entered the minefield that she'd just laid and hit a mine. The consequent explosion caused eight mines still on the rails to detonate, killing 96 or 100 crewmen and sinking the ship in 20 minutes. The protected cruiser

Protected cruiser

The protected cruiser is a type of naval cruiser of the late 19th century, so known because its armoured deck offered protection for vital machine spaces from shrapnel caused by exploding shells above...

  and four destroyers responded to the incident, but Boyarin hit one of Yeniseis mines. The explosion flooded the ship's machinery spaces and her crew abandoned ship. The cruiser remained afloat, but foundered in Dalian Bay the next day during a storm.

On the morning of 15 May 1904, Rear Admiral

Rear Admiral

Rear admiral is a naval commissioned officer rank above that of a commodore and captain, and below that of a vice admiral. It is generally regarded as the lowest of the "admiral" ranks, which are also sometimes referred to as "flag officers" or "flag ranks"...

 Nashiba Tokioki

Nashiba Tokioki

- Notes :...

 led a squadron consisting of the pre-dreadnoughts Hatsuse, Yashima and to bombard Port Arthur. They encountered a field of 50 mines laid by Amur the evening before. Hatsuse hit one mine that disabled her engines and steering and drifted into another mine that caused one of her forward magazine

Magazine (artillery)

Magazine is the name for an item or place within which ammunition is stored. It is taken from the Arabic word "makahazin" meaning "warehouse".-Ammunition storage areas:...

s to detonate. The ship sank in about 90 seconds, taking 496 men down with her. Yashima struck another mine as she maneuvered around the drifting Hatsuse, but she was towed away from the minefield. By the late afternoon Yashimas flooding had become unstoppable and she was abandoned by her crew. Three hours later the ship capsized and sank.

Amur was subsequently besieged in Port Arthur

Siege of Port Arthur

The Siege of Port Arthur , 1 August 1904 – 2 January 1905, the deep-water port and Russian naval base at the tip of the Liaotung Peninsula in Manchuria, was the longest and most violent land battle of the Russo-Japanese War....

and hit in drydock a number of times by 28 centimetres (11 in) howitzer shells on 8 December 1904. She was knocked over on her port side and rested on the side of the dock at an angle of 68°. On 18 December she was hit again by 30 shells and sunk on her side. The Japanese later raised the ship and scrapped it.