Improving Anti-Aircraft capabilities of the QF 4-inch Mk V naval gun

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Fatboy Coxy
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Joined: Thu Jul 19, 2018 5:18 am

Improving Anti-Aircraft capabilities of the QF 4-inch Mk V naval gun

Post by Fatboy Coxy » Wed Jul 25, 2018 8:10 pm

Hi all, apologies for the obscure question, I was looking at the limited anti-aircraft capabilities of the Dragonfly class gunboats.

They were equipped with 2 single QF 4-inch Mk V naval guns, 1 single QF 3.7-inch Howitzer (Which even I know wasn’t capable of an AA role), and 8 single .303-inch anti-aircraft machine guns.

Our friend Wikipedia says the 4-inch guns had a 30 degrees elevation on the Dragonfly entry, probably a CP Mk II mount. This would leave these ships with realistically only a very limited close-range AA capability by way of the .303 machine guns. But other 4-inch Mk V mounts could achieve up to 85 degrees elevation.

Could these mounts be modified, or did the gun have to be dismounted and remounted on a new mount. How difficult was it to build/rebuild/modify these mounts?

dunmunro
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Location: Langley BC Canada

Re: Improving Anti-Aircraft capabilities of the QF 4-inch Mk V naval gun

Post by dunmunro » Thu Jul 26, 2018 1:09 am

Fatboy Coxy wrote:
Wed Jul 25, 2018 8:10 pm
Hi all, apologies for the obscure question, I was looking at the limited anti-aircraft capabilities of the Dragonfly class gunboats.

They were equipped with 2 single QF 4-inch Mk V naval guns, 1 single QF 3.7-inch Howitzer (Which even I know wasn’t capable of an AA role), and 8 single .303-inch anti-aircraft machine guns.

Our friend Wikipedia says the 4-inch guns had a 30 degrees elevation on the Dragonfly entry, probably a CP Mk II mount. This would leave these ships with realistically only a very limited close-range AA capability by way of the .303 machine guns. But other 4-inch Mk V mounts could achieve up to 85 degrees elevation.

Could these mounts be modified, or did the gun have to be dismounted and remounted on a new mount. How difficult was it to build/rebuild/modify these mounts?
For high angle mounts to be effective they need high-angle fire control (which is heavy; see Wikipedia's entry for the Fuze Keeping Clock) and on-mount fuze setters and the associated wiring and indicator dials, which adds even more weight. This is also the reason that a high angle MkXIX 4in gun had little AA potential beyond deterrent value.

Fatboy Coxy
Junior Member
Posts: 13
Joined: Thu Jul 19, 2018 5:18 am

Re: Improving Anti-Aircraft capabilities of the QF 4-inch Mk V naval gun

Post by Fatboy Coxy » Tue Jul 31, 2018 8:46 pm

Hmmm, I think you answered two threads with one post there!

My question was coming from the direction of possibilities of modification of the mounts, and employing them in the smaller ships. I wasn't expecting a particularly effective fire control, not much more than a noisy deterrent. But fire from several, gunboats, corvettes, auxiliary patrol ships, among a convoy might have provided a cumulative reasonable distraction.

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