Author Topic: Antenna Questions  (Read 9424 times)

Offline Karen D.

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Antenna Questions
« on: March 09, 2010, 05:48:45 PM »
Hey Guys,

A friend of a friend has some pretty detailed questions about a model that she's working on. I haven't been able to get the answers she's looking for so I thought maybe someone here could help her out. Her questions and pictures are below...


Dear Karen:
 
       As Jim Fields may have informed you, I am attempting to accurately document a super-detailed 1:72 scale model of the SS-408 Sennet as she was as a gun boat late in 1945. The project will probably take about two years to complete.
 
    I believe that I am clear about how the main (davit style supports P&S) antennae were set up. However, I am quite confused about the whip antenna feed arrangement. (see attached) There appears to be a cable running from the stbd outrigger toward the whip antenna in some pictures yet the cable is missing in others. In some pictures, it looks like a pair of cables (P&S) extending up to the whip antenna. Could the cable(s) be a feed to the whip antenna? One source has indicated that the whip antenna was fed by means of a cable which was secured to the aft radar mast housing.
 
    Additionally, there are two vertically oriented tubular structures secured P&S on the conning tower. Do you have any idea as to what they might be? It has been suggested that they may be flare pots or somehow involved in the rigging of high lines. (see attached)
 
By the way, there is one other question which might be answered by people who "dove" the regular fuel tanks when the ship was in drydock. On my docking plans, several flush type manholes leading to the normal fuel oil tans are shown. Were these closed via portable plates, gaskets and screws or were they welded shut? It has been suggested by one submarine vet that they were probably closed off via a plate which was secured by countersunk screws on APR 2" centers.

    As I am anxious to get as many details correct as possible, any help would be greatly appreciated.

Offline Tom Bowser

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Re: Antenna Questions
« Reply #1 on: March 09, 2010, 07:17:54 PM »
On the Drum the fuel tank covers are bolted on. there are studs welded to the hull and nuts hold the plates down. The studs are 3/4". The verticle tubes were for flares and a lanyard was fed thru the pully and the hole in the side of the sail so the flare could be fired from inside the sail. I don't have any info on the antenas.
Tom

Offline Paul Farace

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Re: Antenna Questions
« Reply #2 on: March 11, 2010, 02:46:32 AM »
The flare tubes are one thing, but the structures pointed out in the photo look to me like the radar detector leads identified in the book "The Fleet Submarine in the US Navy."

The rig was removed as better radar detector systems were introduced. The antenna rigs were changing monthly... the antenna that swings up from the main deck to the shears is just that, one of the several antenna the radio operators could use to communicate (different lengths for different frequencies)... the whip also had an antenna lead but what you point out might be the lanyard that releases the whip when you surfaced. The hydrovane (dogleg shaped metal bracket on the bottom third of the whip) would catch the water as the sub dove and fold the whip down where a ratchet mechanism would lock it down so it was horizonal. When you surfaced someone had to yank the lanyard to release the ratchet and allow the whip to swing upright and vertical. The insulator protected the "yanker" from shocks. The lead for the antenna was bolted to the shears.

Best to set a clearly defined focus date and work from there. These photos show the boat over a significant time period.
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