4.5-Inch BBR Old Faithful
The purpose of the 4.5-Inch BBR (Beach Barrage Rocket), nicknamed Old Faithful, was to provide naval landing craft a means to attack coastal positions in the time between naval gunfire and aerial bombardment, and the time when the troops actually landed on the beach. The rocket was developed by a CalTech (California Institute of Technology) team for the Navy within a short time in summer 1942. A 2.25-inch MK 3 rocket motor of the Mousetrap anti-submarine rocket was fitted with a standard 9 kg (20 lb) general purpose bomb. The resulting rocket first flew on 24 June 1942, and the first combat use of the Old Faithful occurred in November 1942 during the North Africa campaign.
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| Photo: via ORDATA Website |
| 4.5-Inch BBR Old Faithful MK 1 |
The 4.5-Inch BBR consisted of a 2.25" solid-propellant rocket motor, a 4.5" warhead with 3 kg (6.5 lb) of high explosive, a nose-mounted impact fuze, and a circular fin assembly for stabilization. With a burnout speed of only 390 km/h (242 mph) the rocket was relatively slow, and therefore had a rather large dispersion. Nevertheless, it was extensively used as a ship-to-shore bombardment rocket, and a total of about 1.6 million rounds were produced. On some occasions, Old Faithful was even employed as a ship-to-ship or land-based ground-to-ground rocket. There were also slightly longer smoke and incendiary variants of the rocket. In the final phase of the war, the 4.5" BBR was gradually replaced in the beach bombardment role by the more accurate and powerful spin-stabilized 5-Inch HVSR rockets.
The following table lists the 4.5" Rocket MARK/MOD designations for complete Old Faithful rounds:
| Designation | Type | 2.25" Motor | 4.5" Head |
|---|---|---|---|
| MK 1 MOD 0 | HE | MK 7 MOD 0 MK 8 MOD 0 MK 9 MOD 0 | MK 1 MOD 0 MK 2 MOD 0 MK 3 MOD 0 |
| MK 1 MOD 1 | HE | MK 9 MOD 0 | MK 3 MOD 0 |
| MK 2 MOD 0 | Practice | MK 9 MOD 0 | MK 3 MOD 0 (inert) |
| MK 3 MOD 0 | Dummy | MK 9 MOD 0 (inert) | MK 3 MOD 0 (inert) |
| MK 4 MOD 0 | Smoke (FS) | MK 9 MOD 0 | MK 5/7/10 MOD 0 |
| MK 4 MOD 1 | Smoke (WP) | MK 9 MOD 0 | MK 7/10 MOD 0 |
| MK 4 MOD 2 | Smoke (PWP) | MK 9 MOD 0 | MK 10 MOD 0 |
| MK 5 MOD 0 | Incendiary | MK 9 MOD 0 | MK 9 MOD 0 |
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| Photo: via ORDATA Website |
| 4.5-Inch BBR Old Faithful MK 4 |
Specifications
Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!
Data for 4.5-Inch BBR MK 1:
| Length | 76.2 cm (30 in) |
| Diameter | 11.4 cm (4.5 in) |
| Weight | 13 kg (28.7 lb) |
| Speed | 390 km/h (242 mph) |
| Range | 1000 m (1100 yds) |
| Propulsion | 2.25" MK 9 solid-fueled rocket |
| Warhead | 3 kg (6.5 lb) high explosive |
Main Sources
[1] Norman Friedman: "US Naval Weapons", Conway Maritime Press, 1983
[2] Norman J. Bowman: "The Handbook of Rockets and Guided Missiles", Perastadion Press, 1963
[3] Frederick I. Ordway III, Ronald C. Wakeford: "International Missile and Spacecraft Guide", McGraw-Hill, 1960
[4] ORDATA Online Website
[5] Department of the Navy: "OP 1415: Rocket Assemblies, Complete Rounds and Components Data", 11 May 1955
Back to Directory of U.S. Military Rockets and Missiles, Appendix 4
Last Updated: 11 December 2025