Designed
for Submariners

by Hamilton 1:1 Communications, LLC

Fleet Submarine SSK Conversions
Type I & II

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Fleet Submarine SSK Conversions

As early as 1946 the U.S. Navy's Operational Evaluation Group had proposed the use of submarines in ASW, and that September the chairman of the planning group for the Submarine Officers Conference noted that "with the further development and construction in effective numbers of new submarines by any foreign power the employment of our submarines in anti-submarine work may well become imperative". Also, in 1946 the Navy's ASW Conference proposed equal priority for specialized, small ASW submarines as well as the new attack class submarine (i.e. Tang).

A series of Navy ASW conferences and exercises that began in 1947 led to proposals for a hunter-killer submarine (SSK) force to counter the Soviet under-sea fleet. Central to the SSK design was a long-range, passive sonar. The SSK was envisioned as a relatively small, simply constructed submarine capable of mass production.

The principal SSK Sonar was the large BQR-4. The final SSK configuration placed the sonar in a dome at the extreme bow of the submarine, as far as possible from the noise generating machinery and propellers. Under perfect conditions, range out to 35 nautical miles was expected.

The BQR-4 in the SSKs would be supplemented by the high-frequency BQR-2 mounted in a keel dome.  Also fitted in the SSK would be the smaller BQR-3, an improved version of the WWII JT passive sonar.

Congress authorized construction of the first SSK, to be named K-1, in fiscal year 1948, and two more were authorized for the following year.

After the 1948-49 programs, further construction of the K-1 class was delayed until the first units were evaluated. As an interim step, seven fleet boats of the Gato Class were converted to an SSK configuration, their principal alteration being installation of the large BQR-4 sonar and special sound-isolation mountings provided for their auxiliary and propulsion machinery. These large SSKs proved to be highly effective "hunter-killers" for their time. They were superior in performance and habitability in comparison to the small K-boats.

The Fleet Submarines converted to SSK configuration was done by two similar types. They are visually represented by the image below under Boats Converted Type I and Type II?

*Note: (More fleet boat/SSK conversions were planned, but not undertaken, because of the use of nuclear-propelled submarines for the hunter-killer role.)

 


Specifications Type I:

306 length
27' 4” Beam
1,525 tons Surfaced Displacement
2,400 tons Submerged Displacement
2,400 SHP Diesels, 2 Shafts
2,740 SHP Electric Motors, 2 Shafts
15 kt surfaced speed
9 kt submerged speed
300 ft Test Depth

Weapons:

4 x 21” TT Bow
4 x 21” TT Stern

Sensors:

BQS-4 active search sonar
BQR-2B passive search sonar
BQG-4 passive attack sonar


Specifications Type II:

306' 6” length
27' 2” Beam
2,400 tons Submerged Displacement
3,800 SHP Diesels, 2 Shafts
2,740 SHP Electric Motors, 2 Shafts
17 kt surfaced speed
9 kt submerged speed
300 ft Test Depth

Weapons:

4 x 21” TT Bow
4 x 21” TT Stern

Sensors:

BQS-4 active search sonar
BQR-3 passive search sonar
BQG-4 passive attack sonar

BQS-2 (Converted to SQS-10 in 1961)