Coils on deck gun?

[Aktungbby]

https://en.wikipedia.org/wiki/5-inch/25-caliber_gun

5"/25 guns removed from pre-war battleships (especially those rebuilt after Pearl Harbor) had their barrel linings chromed. These guns were remounted for submarine use beginning in late 1943 for extra firepower against small boats and sampans often encountered off the coast of Japan and elsewhere in the Pacific Theater, replacing the earlier 3-inch and 4-inch guns. New production Mark 17 5"/25 guns on the Mark 40 mount designed for submarines became available in mid-1944; USS Spadefish was the first submarine built with this gun. Some submarines had two of these weapons.[2] The Mark 17 gun in the Mark 40 submarine gun mount used semi-fixed ammunition (case and projectile handled separately) and had a range of 14,500 yards (13,300 m) at the maximum elevation of 40 degrees. The submarine mounting had manual elevation, train, and loading with no power assist.
From late 1944 some submarines were built or refitted with two of these weapons. The first of these was USS Sennet, commissioned on 22 August 1944. In February–March 1945 she operated with two other two-gun submarines, USS Haddock and USS Lagarto, in a wolfpack with significant success.To further improve the effectiveness of the two-gun configuration, seven submarines were fitted with a Mark 6 "Baby Ford" fire control computer with a Mark 6 stable element to correct for pitch and roll. The first of these was USS Sea Cat, followed by Flying Fish, Entemedor, Sea Dog, Sea Poacher, Sea Robin, and Sennet. However, some of these refits were completed in September 1945, too late to see action.

Note the 20" recoil BBY!

[1Patriotofmany]

[d@rk51d3]

Anti-Vortex device. On the periscope they were used to eliminate the vortex effect of the water rushing around the scope at speeds of 6 knots and higher, and shaking the daylights ot of them.

Apparently also used on antennas, to keep them stable in high wind.

I'm guessing its the muzzle cap lanyard though, that just looks like a solid coil in the game rendering.

[razark]

I can't recall ever seeing this before. Can anyone provide period photos of this?

[d@rk51d3]

Originally Posted by razark

I can't recall ever seeing this before. Can anyone provide period photos of this?

Deck gun:

http://www.uboataces.com/weapon-deck-gun.shtml


Periscope:



Modern Scope:

[razark]

Ah. So this appears to be more of a u-boat, rather than fleet boat, thing.


I'm no expert, but the vortex explanation seems reasonable.
However:
The periscope is perpendicular to the water flow, while the gun barrel would be parallel to it. Would the same mechanism work for both?

[d@rk51d3]

Originally Posted by razark

Ah. So this appears to be more of a u-boat, rather than fleet boat, thing.


I'm no expert, but the vortex explanation seems reasonable.
However:
The periscope is perpendicular to the water flow, while the gun barrel would be parallel to it. Would the same mechanism work for both?

As per my note above, I don't think the coil on the deck gun is such a device.

I think it's just a bad graphical rendering of the lanyard/rope that secures the muzzle cap/plug to the deck gun platform to prevent its loss overboard.