Fairmile B (ML345)

Fairmile B (ML345)

MGB-61

Dark Adventurer

Fairmile B (ML345)

MGB-61

Dark Adventurer

Britain

II Rank

Battle rating:

AB	RB	SB
2.0	2.0	2.0

Class:

Motor gun boat

Boat

Research:9 200

Purchase:16 000

Show in game

Description

The Fairmile B (ML345) is a rank II British motor gun boat with a battle rating of 2.0 (AB/RB/SB). It was introduced in Update 1.83 "Masters of the Sea" as part of the British fleet closed beta test.

General info

Survivability and armour

Fairmile B (ML345) internals (starboard). Note the ammunition storage in the bow.

Fairmile B (ML345) has the following armour layout:

• 47 mm 3 pdr QF Hotchkiss gunshield: 8 mm, anti-fragmentation armour
• 20 mm/70 Oerlikon Mk.II (single) gunshield: 12.7 mm, hardened armour
• 20 mm/70 Oerlikon Mark V (twin) gunshield: 12.7 mm, hardened armour
• Hull: 28 mm, wood
• Superstructure: 15 mm, wood

While the gunshields may stop low-calibre machineguns, heavy machineguns and cannons will have no trouble with them at any range. The hull and superstructure will not stop any sort of gunfire.

Fairmile B (ML345) can be hull-broken by any gun that is greater than 4 inches (102 mm) in diameter. Hull-break is triggered when any such gun hits and destroys any hull compartment — or in some cases, the bridge — with a high-explosive round, upon which the rest of the boat will be destroyed. At Fairmile B (ML345)'s battle rating, the only guns capable of hull-breaking her are:

• the 114 mm 8cwt QF Mk I, found on Dark Adventurer; and
• the 10.5 cm SK C/32, found on AF D3.

Fairmile B (ML345)'s hull is split into four compartments. The first compartment starts at the bow and ends in front of the bridge, just in behind the pumps; the second ends at the funnel, between the radio station and the engines; the third ends in front of the aft 20 mm/70 Oerlikon Mark V twin mount; and the fourth ends at the stern.

Fairmile B (ML345) has two ammunition storages. The first is located well above the waterline in the bow, below and in front of the fore 47 mm 3 pdr QF Hotchkiss cannon, and holds the ammunition for that gun. The other ammunition storage is located in the stern, just above the waterline in front of the steering gear, and holds the ammunition for both the secondary and the anti-aircraft armament. Destroying either will instantly destroy the boat.

With a crew complement of 18, Fairmile B (ML345)'s overall survivability is average.

Mobility

Mobility Characteristics
Game Mode	Upgrade Status	Maximum Speed (km/h)		Turn Time (s)	Turn Radius (m)
		Forward	Reverse
AB	Stock	37	14	~55.47	~68.66
	Upgraded	50	19	~33.67	~37.21
RB/SB	Stock	32	12	~65.31	~77.96
	Upgraded	37	14	~48.14	~57.46

Fairmile B (ML345) has a displacement of 57 tons.

Armament

Primary armament

The primary armament consists of a single 47 mm 3 pdr QF Hotchkiss cannon mounted on the bow. There are 300 rounds of ammunition available for it. Stock, the mount can traverse horizontally at a rate of 34°/s and vertically at a rate of 21°/s; with the "Primary Armament Targeting" modification installed, this is increased to 40°/s and 25°/s respectively. The gun is single-shot with a nominal rate of fire of 30 rounds/min. With a stock crew, it can be reloaded in 2.6 seconds; with an aced crew, it can be reloaded in 2 seconds.

Primary Armament Guidance
Horizontal	Vertical
±180°	-10°/+70°

There is only one ammunition choice available:

• 3 pdr Mk.2 HE

Penetration statistics
Ammunition	Type of warhead	Penetration @ 0° Angle of Attack (mm)
		100 m	1,000 m	2,000 m	3,000 m	4,000 m	5,000 m
3 pdr Mk.2 HE	HE	4	4	4	4	4	4

Shell details
Ammunition	Type of warhead	Velocity (m/s)	Projectile Mass (kg)	Fuse delay (m)	Fuse sensitivity (mm)	Explosive Mass (TNT equivalent) (g)	Ricochet
							0%	50%	100%
3 pdr Mk.2 HE	HE	571	1.5	0	0.1	132	79°	80°	81°

Secondary armament

For her secondary armament, Fairmile B (ML345) has one 20 mm/70 Oerlikon Mk.II cannon and two 20 mm/70 Oerlikon Mk.V cannons.

The one 20 mm/70 Oerlikon Mk.II cannon is fitted in a single mount, mounted centreline amidships behind the funnel. It has 2,040 rounds of ammunition available. The mount can traverse horizontally at a rate of 75°/s and vertically at a rate of 75°/s. The gun has a belt capacity of 60 rounds and has a rate of fire of 450 rounds/min. With a stock crew, it can be reloaded in 4 seconds; with an aced crew, it can be reloaded in 2 seconds. Its maximum range against surface targets is roughly 2.1 km.

The two 20 mm/70 Oerlikon Mk.V cannons are fitted in a twin mount, mounted centreline aft. It has 4,080 rounds of ammunition available, 2,040 rounds per gun. The mount can traverse horizontally at a rate of 65°/s and vertically at a rate of 65°/s. Each gun has a magazine capacity of 60 rounds and has a stated rate of fire of 450 rounds/min, though in actuality, the gun on the gunner's right side has a slightly greater rate of fire, around 485 rounds/min. With a stock crew, the guns can be reloaded in 8 seconds; with an aced crew, they can be reloaded in 4 seconds. Their maximum range against surface targets is roughly 2.1 km.

Turrets are named sequentially, clockwise, starting at the bow

Guidance for the Secondary Gun Turrets
No.1 Turret (1x 20 mm/70 Oerlikon Mk.II)		No.2 Turret (2x 20 mm/70 Oerlikon Mk.V)
Horizontal	Vertical	Horizontal	Vertical
±147°	-5°/+60°	±140°	-4°/+62°

All guns in the secondary armament group share the same ammunition choices:

• Universal: HEF-T/HEF-I/AP-T

• 20 mm HE: HEF-T/HEF-I/AP-T/HEF-I

• 20 mm AP: AP-T/AP-T/AP-T/HEF-I

Penetration Statistics
Ammunition	Penetration @ 0° Angle of Attack (mm)
	10 m	100 m	500 m	1,000 m	1,500 m	2,000 m
Universal	39	36	29	23	20	17
20 mm HE	39	36	29	23	20	17
20 mm AP	39	36	29	23	20	17

Anti-aircraft armament

For her anti-aircraft armament, Fairmile B (ML345) has four 7.72 mm Lewis 1916 machineguns in two twin mounts, one on either side of the bridge. For each mount, there are 3,880 rounds of ammunition available, 1,940 rounds per gun, for a total of 7,760 rounds. There are no stated horizontal or vertical traverse rates given in-game, but the mounts handle very similarly to, if not exactly the same as, other twin and quadruple 7.72 mm Lewis 1916 machinegun mounts which can all traverse horizontally at a rate of 75°/s and vertically at a rate of 75°/s. Each gun has a magazine capacity of 97 rounds and has a rate of fire of 550 rounds/min. With a stock crew, the guns can be reloaded in 18.2 seconds; with an aced crew, they can be reloaded in 14 seconds. Their maximum range against surface targets is roughly 1.6 km.

Turrets are named sequentially, clockwise, starting at the bow

Guidance for the Anti-Aircraft Gun Turrets
No.1 Turret (starboard)		No.2 Turret (port)
Horizontal	Vertical	Horizontal	Vertical
-30°/+45°	-5°/+50°	-45°/+30°°	-5°/+50°

No ammunition choices are available for this gun. Although not directly stated in-game, the guns fire one tracer round every other round, so they most likely use the standard Default 7.72 mm Lewis 1916 machinegun belt which has the following composition:

• Default: AP/T/AP/T

Penetration Statistics
Ammunition	Penetration @ 0° Angle of Attack (mm)
	10 m	100 m	500 m	1,000 m	1,500 m	2,000 m
Default	20	19	16	13	11	10

Special armament

Mk.VII depth charges numbered 1-14 according to their drop order (click to expand).

Fairmile A (ML100) can carry up to 14 Mk.VII depth charges and 6 Y-gun Mk.VII depth charges.

The 14 Mk.VII depth charges are mounted along the sides of the boat, 7 on either side with 3 in front of the aft gun mount and 4 behind. The depth charges are dropped one at a time in this order (see the image): foremost to aftmost, alternating port and starboard sides, starting with the foremost depth charge on the port side.

The 6 Y-gun Mk.VII depth charges are fired from a Y-gun depth charge thrower mounted in front of the aft gun mount. Aside from the 2 already on the Y-gun, there are an additional 4 depth charges stored just aft of the Y-gun, 2 per side; these lack a visual model but can still be damaged. In the hangar X-ray view, all 4 are present; however, in battle, the forward pair is missing. The remaining aft pair disappears once two depth charges have been fired on their respective sides — in other words, if there is only one depth charge remaining on that side. The Y-gun has one arm pointed to either side of the boat and will fire either the port or starboard depth charge depending on the direction the player is currently looking. After firing a depth charge, there is a reload of approximately 10 seconds.

Before spawning, the detonation time delay for both types of depth charges can be set anywhere between 3 seconds and 10 seconds.

Depth Charge Characteristics (Mk.VII depth charge)
Mass (kg)	Explosive Type	Explosive Mass (kg)	TNT Equivalent (kg)
196	TNT	130	130

Depth Charge Characteristics (Y-gun Mk.VII depth charge)
Mass (kg)	Explosive Type	Explosive Mass (kg)	TNT Equivalent (kg)
196	TNT	130	130

Usage in battles

Like the Fairmile A (ML100), Fairmile B (ML345)'s primary armament, a single 47 mm 3 pdr QF Hotchkiss cannon, is rather poor. This gun is a single-shot weapon, and while its reload is on par with similar calibre single-shot cannons, just like those other cannons, its damage output is abysmal and easily outclassed by any autocannon. The maximum range is also rather bad due to the cannon's low muzzle velocity and low projectile mass. In addition, the accuracy isn't great, and because of the reload in between each shot, correcting aim on targets further than 2 km, or even 1.5 km in many cases, can be quite the challenge. Compared to Fairmile A (ML100), Fairmile B (ML345)'s Hotchkiss cannon has an 8 mm gunshield and can elevate to 70°, though neither makes much of a difference in practice; the gunshield isn't thick enough to stop anything, and the elevation improvement, while nice to have, doesn't make the gun particularly better against aircraft, since it's a single-shot weapon that lacks any airburst ammunition. That said, the Hotchkiss cannon is mounted on the bow on Fairmile B (ML345) which does greatly increase its versatility.

On the other hand, Fairmile B (ML345)'s secondary armament is much better. The secondary armament group consists of three 20 mm Oerlikon cannons. Compared to the Hotchkiss cannon, a 20 mm Oerlikon cannon can deal roughly the same amount of damage over time but on a much more consistent basis. Because of this, a single 20 mm Oerlikon cannon is better than the Hotchkiss cannon, and with three of them at her disposal, it's clear which is the better option on Fairmile B (ML345). The only downside of these guns is that they cannot fire forewards. The single 20 mm/70 Oerlikon Mk.II is unable to fire in a ~65° arc centred forwards; the twin 20 mm/70 Oerlikon Mk.V is unable to in a ~75° arc centred forwards. Along with this, the mounts cannot rotate 360°, though the horizontal turret traverse is fast enough to compensate for this in most cases. Still, it's best to try to keep all enemies to one side of the boat to avoid having to constantly rotate the guns all the way around. As with most autocannons, fire off any remaining ammunition after engagements to guarantee full magazines at the start of the next engagement.

If controlling the secondary armament, be aware that Fairmile B (ML345) is left without any practical anti-aircraft protection. The Hotchkiss cannon is unsuitable against aircraft and the four 7.72 mm Lewis machineguns are very low-damaging. Additionally, the Lewis machineguns can only elevate to 50°, severely limiting its AA potential. Don't rely on the AI gunners to take down aircraft, but it's still a good idea to let them target aircraft; their fire can alert you of any aircraft in the vicinity. By that point, it may already be too late, since the 7.72 mm Lewis machineguns only open fire when the target is within 1 km, well within range for any aircraft to drop its ordnance or strafe with its guns. Always scan the skies for aircraft, and if necessary, switch away from the secondary armament to allow the AI gunners control of the Oerlikon cannons.

Ammunition Choices

For the 20 mm Oerlikon Mk.II and 20 mm Oerlikon Mk.V cannons, the best ammunition choice is the 20 mm HE because it has the highest ratio of HE rounds to AP rounds, meaning that it will be the most effective against both aircraft and surface targets. The 20 mm HE belt should be the main ammunition choice, though a few of the 20 mm AP belt should also be taken into battle for use against armoured targets. There is no reason to use the Universal belt once the other options have been researched.

Depth Charges

Being anti-submarine weapons and with the present lack of submarines in the game, there is practically no reason to use them. While they can be used against surface targets to some success by dropping them right next to a slower target, this is extremely situational. If attempting this, remember the order in which the depth charges drop and that there is no reason to use any depth charge activation time setting above the minimum 3 seconds, since higher delay times means the depth charge will sink further, and thus away, from the target. Again, it should be reiterated that this is very situational.

There is no practical reason to use depth charges in battle, especially since, if they're not dropped, they essentially become unarmoured ammo racks.

Modules

Tier	Seakeeping	Unsinkability		Firepower
I	Dry-Docking	Tool Set		20 mm HE	Anti-Air Armament Targeting
II	Rudder Replacement	Fire Protection System	Smokescreen	20 mm AP	Auxiliary Armament Targeting
III	Propeller Replacement			Improved Rangefinder	Primary Armament Targeting	Depth Charges
IV	Engine Maintenance	New Pumps		Mines	Artillery Support	Bomb mortar

Pros and cons

Pros:

• Good firepower
• Secondary armament: great damage output; large magazine size
• Large amount of depth charges

Cons:

• Ammo rack in the bow
• Primary armament: low damage output; low muzzle velocity; poor accuracy
• Anti-aircraft armament: very low damage output; long reloads; weak against aircraft; bad firing arcs
• Poor top speed and manoeuvrability

History

The Fairmile B motor launch originated as a design of mid-1939 by the Admiralty. At the time, the Admiralty was faced with a severe lack of anti-submarine boats. An existing design by the Fairmile Marine Company, the Fairmile A type, was in the works, but a prototype had yet to be produced. Still, the Admiralty saw many issues with the design, largely stemming from its hard chine hull. The Admiralty created a wooden motor launch design of similar dimensions to the Fairmile A type but with a round bilge hull design instead. This design underwent trials later that year and proved itself to be vastly superior to the Fairmile A type in its seakeeping ability. Impressed by the decentralized production scheme of the Fairmile A type, the contract to mass-produce the new design was awarded to the Fairmile Company with an initial order for 13 vessels placed on 22nd September 1939. Like the Fairmile A type, the Fairmile B type would be manufactured from prefabricated parts under Fairmile's production scheme. Under this system, parts and materials would be sourced from local companies and assembled at Fairmile factories as near to completion as possible. The parts would then be sent in kit form ready for final assembly to any boatyard around the world.

The Fairimile B type, as it was now known, had a length of 112 feet, a beam of 18 feet 3 inches, and a draft of around 5 feet. As originally designed, the boat were to be powered by three Hall-Scott Defender petrol engines, 600 bph each, provided under Lend-Lease from America. However, due to a shortage of supply from the American manufacturer, it was reluctantly decided that the boats should instead be powered by only two engines, the loss in speed deemed acceptable if it meant that 50% more boats could be built. With only two engines, the Fairmile B type could achieve a maximum speed of 20 knots. With a fuel capacity of 2,305 gallons, the boats had a range of 1,500 miles at 12 knots, though above-deck fuel tanks would frequently be added to further increase its range.

Unlike the Fairmile A type, the question of the Fairmile B type's armament determined from the beginning. The Fairmile B type was originally designed for anti-submarine work, specified to be able to carry 12 depth charges and ASDIC sonar. Its intended role was also reflected in its gun armament: one 3-pdr Hotchkiss cannon aft and a pair of Lewis guns forward. Very early on, it was decided that the Fairmile B type should also have the option for variations in its armament. To achieve this, steel strips with tapped holes were installed on the deck onto which any desired armament could be mounted. For the boat to be refitted, all that needed to be done was to unbolt the old armament and swap in the new armament. Because of this, the Fairmile B type could incredibly be entirely refitted in just 48 hours. Due to this modular armament design, the Fairmile B types would often receive many armament refits for a variety of roles — including as minesweepers, minelayers, convoy escorts, submarine chasers, gun boats, air-sea rescue launches, and even as motor torpedo boats — depending on what was needed of them in the areas they were assigned to.

Over the course of World War II, Fairmile B type parts kits would be shipped to various boatyards all throughout the British Empire and Commonwealth. From Jamaica to Singapore, Canada to New Zealand, over 650 Fairmile B types were built from 1940 to 1945. During the war, the Fairmile B types were operated by the Royal Navy, the Royal Canadian Navy, the Royal Australian Navy, the Royal New Zealand Navy, the Royal Indian Navy, the Free French Naval Forces, and the Royal Norwegian Navy, and repeatedly, they proved their worth, making up for their lack of speed with efficiency, versatility, and reliability. After the war, with the need gone for so many boats, many of the surviving boats in Royal Navy service would be scrapped or sold as pleasure boats, though some Fairmile B types were either sold or given to many minor navies, including the Italian Navy, the Royal Netherlands Navy, the South African Navy, the Burmese Navy, the Royal Hellenic Navy, the South African Navy, and the Turkish Navy, which all continued to operate them for many years after the war.

ML-345 was a Fairmile B type motor launch ordered on 21st August 1940. She was built by Diesel Constructors at Isleworth, London and was completed on 30th March 1942. ML-345 survived the war and was eventually sold in 1946.

Media

See also

• Fairmile A (ML100)
• Dark Adventurer
• HMS Liscomb

External links

• Coastal Forces Veterans - Boat Database

Bibliography

• Gaumont British News. (Producer). & White, W. B. (Director). (1941). THE STORY OF THE FAIRMILE PATROL BOAT [Film]. England: Gaumont British News.
• Konstam, A. (2010). British Motor Gun Boat 1939–45 (pp. 12-15, 40-41). Oxford, England: Osprey Publishing. ISBN 978-1-84908-077-4.
• Lambert, J., & Ross A. (1990). Allied Coastal Forces of World War II Volume 1: Fairmile Designs and U.S. Submarine Chasers (pp. 9-28). London, England: Conway Maritime Press. ISBN 0-85177-519-5.