|
The Mark 1 was a simply constructed gun intended to support landing operations. This weapon is also described as a boat gun. Monobloc construction with a Fletcher breech mechanism (down-swinging carrier type) and used a hydraulic recoil piston screwed directly onto the gun. The data that follows is for the Mark 1. |
3"/21 (7.62 cm) Field Guns now at St. Clair,
Pennsylvania
|
Breech and elevation screw of one of the
above cannons
|
| Designation | 3"/21 (7.62 cm) Mark 1 |
| Ship Class Used On | N/A |
| Date Of Design | About 1874 |
| Date In Service | About 1875 |
| Gun Weight | 384 lbs. (174 kg) |
| Gun Length oa | 69.6 in (1.768 m) |
| Bore Length | 64.3 in (1.633 m) |
| Rifling Length | N/A |
| Grooves | N/A |
| Lands | N/A |
| Twist | RH 1 in 29.89 |
| Chamber Volume | N/A |
| Rate Of Fire | about 8 - 9 rounds per minute |
| Type | Bag (?) |
| Projectile Types and Weights | HE - 13 lbs. (5.9 kg) |
| Bursting Charge | N/A |
| Projectile Length | N/A |
| Propellant Charge | N/A |
| Muzzle Velocity | 1,150 fps (351 mps) |
| Working Pressure | 9.5 tons/in2 (1,500 kg/cm2) |
| Approximate Barrel Life | N/A |
| Elevation | With 13 lbs. (5.9 kg) Shell |
| Range @ 19.5 degrees | 5,000 yards (4,570 m) |
| No information available for boat guns, although I would suspect that a simple pedestal type mounting was used. Maximum elevation was slightly greater than 19.5 degrees. |