Light artillery in Sweden – Cold war experience

Light Coastal artillery in Sweden

During the Second World War, a very large number of light Coastal Artillery batteries were built, mostly consisting of older ship parts. These batteries were usually built under great time constraints and were also quite spartan in terms of placement and endurance. Protection against nuclear weapons and collective gas protection were lacking, and the batteries thus quickly became out of date after the war.

Light coastal artillery cannon M/05-10

This piece type was originally artillery on the old coal-fired destroyers. A total of 15 7.5 cm m/05 and 13 7.5 m/05-10 were acquired. Of these, 21 were used for new light fixed coastal artillery in bunkers during the fifties (3 pieces in each battery).

The batteries have fire control Arte 708, which consists of electromechanical central instrument (CS 704), radar (PS-72), optical periscope and optical range finder.

The batteries that belonged to KA1 are rebuilt older 57 mm batteries.

Nr	Code	Name	Place	Finished	Closed
1	GE 2	Bönan	Bönan Grubban, Gävle	1956	1984
2	M2	Västra batteriet	Mellsten	1957	1975
3	GE3	Furuskär	Furuvik, Gävle	1957	1984
4	KH	Korsöhals	Korsöhals	1957	1975
5	SL2	Grönviken	Grönviken, Alnön, Sundsvall	1958	1984
6	SL3	Raholmen	Raholmen, Alnön, Sundsvall	1958	1984
7	VÖ/RN3	Vässarö	Vässarö	1961	1975

7.5 cm turret gun w/57

7.5 cm turret gun m/57 is a light fixed coastal artillery piece, developed by Bofors for the Swedish coastal artillery in the late 1950s. It was primarily intended to replace a very large number of older systems that primarily consisted of 57 mm guns of varying model years. The cannon type was produced in a relatively large series, where Sweden built 30 three-piece batteries and purchased a movable version called 7.5/65, and 16 fixed pieces were exported to Norway. In Sweden and Norway, all batteries are closed.

The cannon is mounted in an armored turret, with an ammunition tray at least 5 meters below ground level. Since the early 1970s, the tower has been fitted with a stone-like masking hood made of fiberglass, which makes it significantly more difficult to detect. The playground also has a ground attachment fork in which the fire tube rests when not in use, which reduces the risk of damage from overpressure and ground shaking caused by nuclear charge explosions. When the piece is not in use, the fire tube is fitted with a fiberglass cover called the ”crocodile” to improve masking.

Turret gun 7.5/57 is a semi-automatic air-cooled artillery gun with vertical wedge mechanism and homogeneous fire tube equipped with powder gas ejector. It uses unit cartridges that are fed from an underground ammunition magazine by means of an elevator. This is fed with ammunition by hand by inserting cartridges into a revolver mechanism in the lower part of the elevator. The loading of the cannon is semi-automatic and takes place by the loader manually operating a handle whereby the cartridge is automatically brought to the correct angle, fed into the cartridge position and the wedge is closed. Empty casings are ejected backwards and fall through a pipe that leads down into a wood-clad room near the ammunition bin. Normal manning for a cannon is 7 men, of which 3 (cannon commander as well as side sight, elevation sight, loader) are in the tower and the remaining 4 (ammunition officer, magazine filler and 2 ammunition hoses) serve the ammunition tray. Added to this are personnel for measuring stations, management/liaison, rope/medical care and close protection (ground combat units).

There are four versions of the cannon, m/57 and m/57B-D, which deviate slightly from each other in terms of elevator length (and thus the depth of the cannon well), production technology for the armored cupola and the presentation equipment of the fire line:

m/57 has a long elevator and a mezzanine in the gunwell, welded armor cupola and companion for the Ci 710.
m/57B has short elevator, cast cupola and companion.
m/57C has short elevator, cast cupola and ArtE 719 directional indicators
m/57D has short elevator, welded dome and companion.

Series 1

The first 8 batteries were built with a central tunnel containing fire line, power supply and emplacement, and with tunnels leading out to staging areas at each piece location. In some cases the terrain was allowed to rule and the tunnels to the pieces were not built, but in all cases the entire battery is dependent on the functions of the central tunnel. The construction technique meant that a larger tunnel was blown up, in which a concrete structure with a vaulted roof was built, designed to withstand great stresses such as falling boulders. The concrete construction also contributes to creating a good indoor environment in the facility, together with a powerful ventilation and dehumidification system with overpressure capability as protection against, among other things, gas and radioactive fallout. Good ventilation is also a necessity to keep radon levels at acceptable levels when the facility is occupied.

Nr	Code	Namn	Place	Finished	Closed
1	LN	Ljungarn	Sjausterhammar, Gotland	1962	1995
2	DL2/HÖ2/HU	Hemsön	Havstoudd, Hemsön	1964	1994
3	OD	Oxelesund	Femöresfortet	1964	1997
4	HO3	Holmsund	Bredskär	1964	1997
5	KM2	Karlshamn	Sternö, Blekinge	1964	1997
6	SI	Simrishamn	Gladsax, Skåne	1964	1993
7	MB	Mörtö-Bunsö	Nära Dalarö	1965	1995

Series 2

Series 2 consisted of 10 batteries and represented a step towards increased nuclear protection through increased independence for the individual units and increased clearances. They still used the same construction technique as for series 1, with concrete structures placed directly against the rock. Here, however, they began to build the gun emplacements in sunken shafts which were then poured over with concrete, while the central tunnel was built in the same way as in series 1.

Nr	Code	Name	Place	Finished	Closed
8	KN	Kolgårdsholmen	Kolguskär, Landsort	1966	2000
9	RU	Råstensudde	Norra Singö	1967	2000
10	AD	Arkösund	Bergön, Bråviken	1967	1995
11	MÖ	Malmö	Lernacken	1967	2000
12	YD2	Ystad	Svarte	1967	1999
13	GÖ	Galterö	Göteborg	1968	2000
14	SE2	Slite	S:t Olfosholmen, Gotland	1968	1997
15	SL4	Sundsvall	Nyhamn	1968	1994
16	LÅ	Långskär	Söderarm	1969	1997
17	LK	Lysekil	Kornö, Nära Dalarö	1970	1995
18	VG2/HÖ3	Hambergsudden	Hambergsudden, Härnön, Härnösand	1970	1994

Series 3

The 12 batteries in the Series 3 represented a significant upgrade for the 7.5/57 system. Nuclear weapon protection was prioritized, and the hatches were therefore made even stronger. With the exception of electric power, each unit was built as an independently functioning facility and the installation standard was slightly increased. Since the method of concrete structures mounted close to the rock proved to provide poor protection against ground shaking, they were replaced with elastically suspended steel buildings which were also provided with adequate EMP protection. Here, too, the facilities, including the central facility (now called s-plats), were built in sinkholes which were then poured over with concrete.

Nr	Code	Name	Place	Finished	Closed
19	GI	Gisslingö	Söderarm	1971	1997
20	FÅ	Fårö	Ryssnäs, Gotland	1971	2000
21	JV	Järnavik	Tärnö-Harö, Blekinge	1971	1997
22	KP	Kappelshamn	Gotland	1972	2002
23	EN	Ellenabben	Aspö, Blekinge	1972	2000
24	RN4	Roten	Södra Singö, Uppland	1972	?
25	STE2	Trelleborg	Maglarps distrikt	1973	1997
26	SA2	Söderarm	Båtskär, Uppland	1973	1997
27	MS4/YG	Mällsten	Yttre gården, Nynäshamn	1973	1999
28	BÅ	Bråviken	Kungshamn, Nyköping	1974	2000
29	MD	Marstrand	Koön	1975	2000
30	KO2	Korsö	Vindalsö	1975	1997

Common characteristics

Auxiliary power was provided by 2 Scania diesel generators, with enough fuel for 60 days of operation. Water was supplied by a saltwater intake (for toilets, showers etc.) and a drilled well for fresh water. Each battery had a number of dummy turrets which basically consisted of the fiberglass hood, a steel pipe and a heat source which was placed inside the dummy turret to give it an IR signature. Dummy rangefinders and targeting radars was also built. A number of shelters (type SK10) and prepared foxholes were provided for the close-in defense troops.

Fire Control, series 1 and 2

The first fire control system developed for 7.5/57 was Ci 710 (Central Instrument 710). This consisted of a mechanical ballistics computer, a periscope and a radar installed in the battery command post. An additional search periscope and radar PPI was provided as well as an optical rangefinder in the reserve command post. This was replaced with the world’s first operative military laser rangefinder, an Ericsson design called AML 701, starting in 1968. The Ci 710 computer was built by Arenco and would take its input from either the radar, periscope or laser rangefinder and produce parallax corrected firing parameters for the three guns. The gun crew was provided with analog displays which would show traverse and elevation which they then had to manually follow.

Fire Control series 3

For the new Series 3 batteries a new fire control system called ArtE 719 was developed by Philips Elektronikindustrier AB (PEAB). This eliminated the periscopes, replacing them with a remote controlled low-light TV system with an integrated laser rangefinder thus enabling the command post to be located away from the ranging station. Also, the radar was completely replaced with a more modern unit. It featured an analog electronic calculation unit which could track 2 targets simultaneously, as well as digital transmission of normalized target parameters to a computer at each gun emplacement where its individual firing parameters would be calculated. The gun crew, however, still had to lay their gun manually as automatic control was not included. The two target trackers allowed for engaging two targets simultaneously, with the guns firing a number of salvos on target 1 and then shifting to target 2 and firing on it while the shells to target 1 were in the air, after which the cycle was repeated as necessary. Short-term rate of fire was about one shell every other second.