8"/30 caliber gun

8"/30 caliber Mark 1 & 2 Naval Gun
USS Boston's forward 8"/30 gun is in the right foreground, with its crew standing at their posts.
Type Naval gun
Place of origin United States
Service history
In service 1886–1906
Used by  United States Navy
Wars
Production history
Designer Bureau of Ordnance
Designed 1883
Manufacturer U.S. Naval Gun Factory
Produced 1886–
No. built
  • Mark 1: 4 (Nos. 1–4)
  • Mark 2: 4 (Nos. 5–8)
Variants Mark 1 Mod 0 and 1 and Mark 2 Mod 1
Specifications
Weight 29,100 lb (13,200 kg) (without breech)
Length
  • 257.99 in (6,553 mm) Mark 1 Mod 0
  • 254.6 in (6,470 mm) Mark 1 Mod 1
  • 255.6 in (6,490 mm) Mark 2 Mod 1
Barrel length
  • 240 in (6,100 mm) bore (30 calibers)
  • 244.78 in (6,217 mm) bore 30 calibers
Shell 260 lb (120 kg)
Caliber 8 in (203 mm)
Elevation −5° to +20°
Traverse −150° to +150°
Rate of fire 0.5–1 round per minute
Muzzle velocity 2,000 ft/s (610 m/s)
Effective firing range 14,000 yd (13,000 m) at 20° elevation

The 8"/30 caliber gun (spoken "eight-inch-thirty-caliber") formed the main batteries of the United States Navy's "New Navy". They were a US naval gun that first entered service in 1886, and were designed for use with the first three protected cruisers, Atlanta, Boston and Chicago.[1]

Mark 1

Mark 1, Nos. 1–4, Mod 0, consisted of a tube, jacket, 19 hoops and an elevating band with integral trunnions. The Mod 1 had no trunnions and were not hooped to the muzzle. They weighed 29,100 lb (13,200 kg), without the breech, with a barrel length of 240 in (6,100 mm) bore (30 calibers).[1][2]

Mark 2

The Mark 2 Mod 1, Nos. 5–8, was similar, but had the hoops differently arranged, did not have integral trunnions and had its rear sights controlled by worm and miter gears. Mark 2 gun No. 7, from Chicago, was later modified into a pneumatic gun and mounted in Vesuvius to fire a 10 in (254 mm) aerial torpedo.[1][2]

Ship Gun Installed Gun Mount
USS Atlanta (1884) Mark 1: 2 × 8"/30 caliber Mark 1: 2 × Single Barbette Mount
USS Boston (1884) Mark 1: 2 × 8"/30 caliber Mark 1: 2 × Single Barbette Mount
USS Chicago (1885) Mark 2: 4 × 8"/30 caliber Mark 2: 4 × Single "Half-turret"

On display

Two guns from the cruiser Boston are currently (2010) on display at Hamlin Park in Shoreline, Washington. A plaque at the site states that one of these guns fired the first shot at the Battle of Manila Bay on 1 May 1898. Another plaque states

             8-inch 30 Caliber Gun
                 U.S.S. Boston
   Captain Frank Wildes, U.S. Navy Commanding
            This gun is credited at
           THE BATTLE OF MANILA BAY
         with dismounting three guns
                  in the
           Spanish fort at Cavite
                May 1, 1898

[3] The two guns from Boston are marked "U. S. NAVY 8in MARK II 1899 CONVERTED".

Notes

References

Books
  • Friedman, Norman (2011). Naval Weapons of World War One. Seaforth Publishing. ISBN 978 1 84832 100 7.
Online sources
  • "United States of America 8"/30 (20.3 cm) Marks 1 and 2". Navweaps. 29 July 2016. Retrieved 19 October 2016.
  • "7 Odd Things to See in Seattle Parks (North End Edition)". The Sun Break. 8 June 2013. Retrieved 9 November 2015.

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