Original 1955 prototype for Swimmer Delivery Vehicle

[johnscura]

Recently purchased an Aerojet Mark VII mini sub from Southern California. This 1955 model was one of the original prototypes for a UDT Swimmer Delivery Vehicle. I believe it was designed and built in 1955 by Aerojet General at their Azusa CA plant. During 1952-1955, Lt. Cmdr. Fane worked with Calvin Congwer, an engineer at Aerojet-General in Los Angeles, to development of diver transport vehicles such as the Swimmer Propulsion Unit (SPU) and the Minisub MK VII. I do not believe this model was put into service but as I understand things from this web site it was evaluated for duty by UDT, RCN, and RN. My unit appears to be working order as powered by pedals and twin counter rotating propellers. Its battery box is still present but motor and electrical controls that were present at one time are currently missing. Photo below shows mine (crude mermaid painted on side by previous owner) and another version with original paint that was on display at the Museum of Man in the Sea in Panama City Beach FL. Unfortunately this particular sub was on display outside the museum and it was destroyed by a hurricane. Fun fact: One of these units appeared in a Sea Hunt episode (Season 1 episode 12).

I am looking for more information on this particular design, such as prop rotation speed, weight, evolution of design among the prototypes built, and anything else that is available. Also very much interested in how many units were made, how many still exist, and if any are still functional.

 

[Boxman]

This film was posted to YouTube today (12-May-2025) by Periscope Film. It features underwater footage of the Aerojet Swimmer Propulsion Unit Mark II and the Aerojet Swimmer Propulsion Unit Mark V. It would seem the latter unit was also known as the Aerojet Aquaped. The USS Quillback (SS-424), in pre-GUPPY form, also makes a cameo appearance in the footage, which would date it to sometime around or before April 1952, when she was decommissioned prior to her GUPPY rebuild.

YouTube - Periscope Film: UNDERWATER DEMOLITION TEAM UDTs / U.S. NAVY SEALs SWIMMER PROPULSION UNITS SPUs FOOTAGE GG30775b

Here is more on the Swimmer Propulsion Unit Mark II, posted at The Naval SEAL Museum (link):
Combatant Submersibles – Part II
A Photographic History: 1947 – 1960
By Tom Hawkins

Aerojet Mini-Sub Mark II (1952). The Aerojet Mini-Sub Mark II was a further improvement of the Aerojet Mark I SPU through the addition of a CO2 propulsion system. This was in addition to the pedal-drive system. It was a one-man submersible. A steady-state speed of three knots for three miles could be achieved with the pedal-drive system. Using C02, the SPU was capable of four knots for 15 minutes.

 

[johnscura]

This film was posted to YouTube today (12-May-2025) by Periscope Film. It features underwater footage of the Aerojet Swimmer Propulsion Unit Mark II and the Aerojet Swimmer Propulsion Unit Mark V. It would seem the latter unit was also known as the Aerojet Aquaped. The USS Quillback (SS-424), in pre-GUPPY form, also makes a cameo appearance in the footage, which would date it to sometime around or before April 1952, when she was decommissioned prior to her GUPPY rebuild.

YouTube - Periscope Film: UNDERWATER DEMOLITION TEAM UDTs / U.S. NAVY SEALs SWIMMER PROPULSION UNITS SPUs FOOTAGE GG30775b

Here is more on the Swimmer Propulsion Unit Mark II, posted at The Naval SEAL Museum (link):
Combatant Submersibles – Part II
A Photographic History: 1947 – 1960
By Tom Hawkins

Had not seen this. Thanks for the heads up.