by Grandahi » Wed Jul 28, 2021 2:08 pm
Tom Dougherty wrote:That�s an interesting factoid! I have never seen a J screw with the 11 blade attenuator on it. How widespread was it employed? What time era (1990�s?) was the attenuator added to the 637�s? Any idea on the effectiveness?
My understanding is it was a response to the Russian installation of the SOKS wake detection system. The attenuator seemed to come and go in a short period. I was never clear on whether the 688I ring screw was to control tip vortices or to protect the prop tips under ice. Or both.
Unfortunately I cannot comment on how widespread the employment was, only physically seeing it on two different boats, Aspro and Tunny. I was on board and decommissioned Aspro from 1992-1995, and Tunny from '95-'96. This was in Pearl Harbor btw. Other boats that were there at the time besides the usual 637s and 688s, were USS Kamehameha (SSBN/SSN-642), undergoing conversion to SSN (and the reason we never carried the DDS on Tunny during my time on her), and USS Haddock (SSN-621), which came to Pearl for inactivation and decommissioning. Fun factoid, ex-USS Aspro and ex-USS Haddock were towed together in 1995 back to Washington for recycling.
I always figured the device was installed as part of Aspro's overhaul at Mare Island ca. 1989-90, which I believe is when she got SHT, sonar and fire control upgrades, etc. With those upgrades we could do all and more than 688s, except go as fast.
For the most part we were too busy keeping her (Aspro) in a state of readiness to really delve into when which equipment got put on. Tunny was in MUCH better shape, even for being just a few years younger . . .
[quote="Tom Dougherty"]That�s an interesting factoid! I have never seen a J screw with the 11 blade attenuator on it. How widespread was it employed? What time era (1990�s?) was the attenuator added to the 637�s? Any idea on the effectiveness?
My understanding is it was a response to the Russian installation of the SOKS wake detection system. The attenuator seemed to come and go in a short period. I was never clear on whether the 688I ring screw was to control tip vortices or to protect the prop tips under ice. Or both.
[/quote]
Unfortunately I cannot comment on how widespread the employment was, only physically seeing it on two different boats, Aspro and Tunny. I was on board and decommissioned Aspro from 1992-1995, and Tunny from '95-'96. This was in Pearl Harbor btw. Other boats that were there at the time besides the usual 637s and 688s, were USS Kamehameha (SSBN/SSN-642), undergoing conversion to SSN (and the reason we never carried the DDS on Tunny during my time on her), and USS Haddock (SSN-621), which came to Pearl for inactivation and decommissioning. Fun factoid, ex-USS Aspro and ex-USS Haddock were towed together in 1995 back to Washington for recycling.
I always figured the device was installed as part of Aspro's overhaul at Mare Island ca. 1989-90, which I believe is when she got SHT, sonar and fire control upgrades, etc. With those upgrades we could do all and more than 688s, except go as fast.
For the most part we were too busy keeping her (Aspro) in a state of readiness to really delve into when which equipment got put on. Tunny was in MUCH better shape, even for being just a few years younger . . .