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PostPosted: Sun Jul 12, 2020 11:05 am 
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Good news! I have asked Micro-Mir to manufacture a plastic model kit of the Ethan Allen. Tom Dougherty and I forwarded drawings and pictures of the boat and Micro-Mir has agreed to produce a kit of the boat with a target for December. Let's hope that they adhere to this!

Bill


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PostPosted: Tue Oct 06, 2020 1:39 am 
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Thanks Bill. Really good news
I never really thought Polar Bear productions would get to it so it's great to hear MIcro-Mir is still going strong with this project and has a projected release date.

I have been watching their Facebook page but nothing posted yet on the 608 boat.

(Pssst... get your order in early as they may make this a short run as they have done with other recent kits like their 1/144 USS Monitor, which has still not sold-out.)

Jim.


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PostPosted: Wed Feb 10, 2021 11:42 am 
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Bill, You are THE MAN!
Micro_Mir came through.

Just posted on one Overseas retailer's site...ModelsUA.

Image


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PostPosted: Wed Feb 24, 2021 7:02 pm 
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Noticed that SSBN 610 Thomas A. Edison has some kind of large dome (sonar?) on the bow. Do any of the experts know what this was and if any of the other Ethan Allen class boats have it?


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PostPosted: Thu Feb 25, 2021 4:52 am 
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That dome was for the HINDSIGHT (BQR-16?) sonar, which was intended to allow SSBNs to have sonar coverage in their baffles. Some of the 598 class had a dome in the trailing edge of the sail, which didn't last long as was exceptionally good at picking up noise from the engine room. Towed arrays streamed from the sail were also considered (the Jefferson had a prototype). Eventually most of the 608 class got the big bow dome for HINDSIGHT. I would love to know more details about this specific installation, but I have found little. It could not have seen directly aft, but perhaps it had better directivity looking aft than the BQR-2 and BQR-7. Eventually the BQR-7 was deemed sufficient for this purpose and the domes were removed. Ultimately sonar coverage in the baffles was provided by the BQR-15 towed array.

Jacob

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PostPosted: Thu Feb 25, 2021 7:26 am 
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Thank you. Unfortunately I do not think an after-market dome will become available but I might try to carve one - would make an interesting variation.


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PostPosted: Thu Feb 25, 2021 4:50 pm 
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Just to keep the terminology straight so I'm not misunderstanding what your question refers to, sonar sensors are protected by fairings, (these protrude from the exterior) windows, which usually conform to the exterior, and domes, which cover the entire bow (--that's why they're dome-shaped.) Chin mounts, (on older, and now VA-class boats) are attached to the lower portion of the bow.

The fiberglass fairing on the top of the 608 class bow protected the upper, (there's another one on the keel) low freq hydrophone for the WLR-9 acoustic intercept receiver. The (much smaller) upper (high freq) hydrophone was on top of the sail. The WLR-9 processed and displayed information about any active sonar emissions including torpedo homing sonars. It used five different alarms to alert the sonar shack which b!tch was which, without having to even look at it. Reporting the results on the display was the job of the sonar sup under normal watch-standing conditions. During battle stations, it had a dedicated operator.

Nearly all US submarines (warfighters, anyway) had this Norden-built system when it came out and newer versions exist to this day.

The closest thing to a rear-looking passive sonar was an experiment conducted using a circular BQR-2 array mounted to the rear/upper end of the sail that wasn't worth much and didn't last long. With the introduction of towed arrays in the early 70's, (BQR-15 /STASS) an improved, long-range detection method for the area surrounding the ship became available, but for the baffles that was not enough because of the (very low) frequency coverage of the array. Towed arrays offer 360 coverage, not just behind the platform as is generally believed.

A bow-mounted sonar protected by a dome cannot "listen through" the ship. This is why the God of Acoustics created "The Baffles" which students were acquainted with during the first week of basic submarine sonar "A" school.

Submarines "clear baffles" at random intervals and prior to excursions to periscope depth by executing a (min 90 degree) turn and exposing their listening beams to the formerly obscured areas behind the ship with their passive sonars.

The older, main analog sonars, (BQR-2, BQR-4, BQR-7) could manually sweep their listening beams in azimuth using small handwheels, the operator used their ears and several indicators to determine when the listening beam was dead nuts-on the bearing with the highest noise level. Digital sonars like the BQR-21, BQQ-5, and BQQ-6 use digital processing to ultimately display information that automatically updates at different rates to present acoustic data. The fastest update rates (called integration time averaging) are the least accurate compared to longer update rates which smooth out the signal for a better target track. Multiple averaging rates are assigned on the consoles to provide the best overall acoustic picture.

If a noise level met detection criteria, an analog or digital tracker was assigned, and locked onto the contact, tracking it automatically. That data was made available to fire control for detailed contact tracking purposes and weapons employment if necessary. Other sensors like radar, ESM, and periscopes could provide data to refine the tracking solution, since sonar bearings can be several degrees off, depending on several factors.

During the Cold War, the Soviets had a nasty habit of reversing course to monitor their baffle area, since their sonars weren't as advanced and US boats held a commanding acoustic (radiated self-noise) advantage.

A high percentage of sonar information found online is erroneous, contradictory, and misleading. The words "hydrophones" and "transducers" are often used interchangeably, but they have completely different purposes.

CC


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PostPosted: Thu Feb 25, 2021 9:59 pm 
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CC,

The dome that FRAMSailor is referring to is not the WLR-9, but rather the large HINDSIGHT dome (dome is not incorrect terminology in this case):

http://navsource.org/archives/08/609/0861003.jpg

Also, the 608 class had the French-made DUUG-1 before they received the WLR-9:

http://navsource.org/archives/08/609/0861001.jpg

Jacob

_________________
Under Construction:
1/350 Typhoon
1/350 Skate
1/350 USS Nautilus
1/350 Tang
1/350 November
1/350 Hotel II
1/350 Alfa
1/350 George Washington
1/72 Type VIIC


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PostPosted: Fri Feb 26, 2021 5:26 am 
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Never saw any pictures posted by the FRAMSailor (other than two sets of box art) only a reference to a dome on a bow. And yes, I'm well acquainted with the DUUG, having posted about it on this site previously. The DUUG (made obsolete by the WLR-9) was still installed in the Attack Team trainers we used in Pearl during off-crews in the late 70's.

Technically, the 609 is sporting a fairing on the bow. 608's and 598's had steel "windows" on their bows with torpedo tubes between them. The BQR-7 was on top and the BQR-2 (BQR-21 which replaced it on the 608's) was located on the bottom. True domes are used to cover spherical arrays. They are huge structures typically made from GRP.

CC


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PostPosted: Fri Feb 26, 2021 7:55 am 
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Here is another photo of the "dome" to which I was refering.

http://navsource.org/archives/08/609/0861016.jpg


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PostPosted: Fri Feb 26, 2021 6:08 pm 
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Thanks, now what you were referring to makes sense! That's an experiment that didn't pass the evaluation.

Call it whatever you want; "dome" has been used interchangeably for so long, it's to the point where it's lost it's original meaning. Skimmers have always called their bow-mounted curb feelers domes. But then . . . they're skimmers.

CC


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PostPosted: Fri Feb 26, 2021 6:23 pm 
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It's all a matter of semantics of course and it doesn't really matter in the grand scheme of things, but I will reiterate that technically it is not incorrect to call that HINDSIGHT dome a dome. You can find numerous examples of such structures being referred to as domes in official documents. Here is just one example:

https://i.imgur.com/cuMSOvo.jpg

Also, rather amusingly, Donald Kern (head of submarine preliminary design at BuShips) called the HIDSIGHT dome a pod:

https://www.alternatewars.com/WW3/WW3_D ... cerpts.htm

Jacob

_________________
Under Construction:
1/350 Typhoon
1/350 Skate
1/350 USS Nautilus
1/350 Tang
1/350 November
1/350 Hotel II
1/350 Alfa
1/350 George Washington
1/72 Type VIIC


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