5"/25 on shore bombarment

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OpanaPointer
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Re: 5"/25 on shore bombarment

Post by OpanaPointer »

Sounds quite reasonable.
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marcelo_malara
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Re: 5"/25 on shore bombarment

Post by marcelo_malara »

Byron Angel wrote: Mon Sep 26, 2022 12:01 am Hi Marcelo,
Those projectiles sitting in the fuze-setters might have been "insurance" against possible kamikaze intruders, which were prone to coming in at all sorts of odd hours, singly, severally and from any direction or height. Saipan was kind of in the middle of the Kamikaze campaign (after Leyte Gulf, before Okinawa) and those 5in/25s represented the long-range HAA defence of the ship.

Just a thought.

Byron
Yes! I didn´t think that. Totally plausible. The shell bearers are seen behind the guns and not close to the fuze setters, one would expect they to be there to take the shells just set to the guns.
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Re: 5"/25 on shore bombarment

Post by Byron Angel »

Hi Marcelo,
One “loose string” in my thinking might be .... what about VT shells? I do not offhand recall whether the 5in/25 were issued with VT ammunition (but I know where to look when I get a chance). On the other hand, the shells sitting in the fuze-setters must by definition be mechanically-fuzed. These were still used in large numbers (about 25-30pct IIRC) even after large scale introduction of VT ammunition as marking rounds to alert CAP and check FC solutions (not every ship had the Mk37 GFCS for its HAA battery - and one drawback of VT she’ll was that it would only explode if the fuze was activated by passing within lethal distance of an aircraft.

These rabbit holes always go so much deeper than we think.

Byron
OpanaPointer
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Re: 5"/25 on shore bombarment

Post by OpanaPointer »

Forward observer marks VT shell explosions. When they are on the money the conventional shells follow. (One poss. method.)
Byron Angel
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Re: 5"/25 on shore bombarment

Post by Byron Angel »

Hi Marcelo,
Yes, the 5-in/25cal was issued VT AAC ammunition. So those rounds in the fuze-setters likely must have been for target marking.


Hi Opanapointer,
Good question. I assume you are talking land bombardment? I imagine that a VT-fused HE bursting in the air must be pretty visible - especially in the case of targets sheltering in wooded areas. OTOH, I recall reading that VT-fuzed artillery shells themselves, when introduced at the Battle of the Bulge, were found to be devastating against sheltered (i.e. dug-in enemy personnel) - far more so than conventional contact-fuzed HE.

B
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marcelo_malara
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Re: 5"/25 on shore bombarment

Post by marcelo_malara »

Byron Angel wrote: Tue Sep 27, 2022 6:04 pm Hi Marcelo,
One “loose string” in my thinking might be .... what about VT shells? I do not offhand recall whether the 5in/25 were issued with VT ammunition (but I know where to look when I get a chance). On the other hand, the shells sitting in the fuze-setters must by definition be mechanically-fuzed. These were still used in large numbers (about 25-30pct IIRC) even after large scale introduction of VT ammunition as marking rounds to alert CAP and check FC solutions (not every ship had the Mk37 GFCS for its HAA battery - and one drawback of VT she’ll was that it would only explode if the fuze was activated by passing within lethal distance of an aircraft.

These rabbit holes always go so much deeper than we think.

Byron
Yes, they have VT fuzes, from navweaps:

HC Mark 36: 53.85 lbs. (24.43 kg)
AAC Mark 28 Mods 1 to 8 2 3: 54.0 lbs. (24.49 kg)
AAC Mark 36 2 3: 53.85 lbs. (24.43 kg)
VT AAC Mark 28 Mod 9 3: 51.7 lbs. (23.45 kg)
VT AAC Mark 36 Mods 2 and 4 3: 54 lbs. (24.49 kg)

Illum Mark 25 Mod 2: 54.5 lbs. (24.7 kg)
Illum Mark 27 Mods 1 to 4: 53.65 lbs. (24.33 kg)
Illum Mark 27 Mods 5 to 10: 54.5 lbs. (27.7 kg)
Illum Mark 45 Mod 0: 54.5 lbs. (27.7 kg)

May be there were not enough?
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marcelo_malara
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Re: 5"/25 on shore bombarment

Post by marcelo_malara »

Byron Angel wrote: Tue Sep 27, 2022 8:33 pm So those rounds in the fuze-setters likely must have been for target marking.

How would this work? I mean target marking with time-fuzed shells instead of impact fuzed shells.
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Re: 5"/25 on shore bombarment

Post by Byron Angel »

marcelo_malara wrote: Tue Sep 27, 2022 8:43 pm
Byron Angel wrote: Tue Sep 27, 2022 8:33 pm So those rounds in the fuze-setters likely must have been for target marking.

How would this work? I mean target marking with time-fuzed shells instead of impact fuzed shells.

Hi Marcelo,
I picked up on this from the profuse reflections and studies prepared by the USN in connection with the Kamikaze campaign. A VT projectile would only burst if it flew within fuze-triggering distance of an aircraft (70ft? IIRC). AA fire control, even the radar-assisted Mk37, was not by any means that accurate, especially out beyond, say, 6,000 yards ... in which case the VT-fuzed projectilef could easily miss by a distance far greater than their fuze-initiating radius and simply sail on invisible to both eye and radar.

The solution was to open fire against more distant targets with mechanically-fuzed ammunition which would more or less reliably burst no matter how distant they passed by the target aircraft. They were used not only to correct own ship's HAA fire, but also to alert nearby ships and aloft CAP aircraft to incoming enemy that they might not necessarily have yet spotted.

I was, to be honest, surprised by the amount of mechanically fuzed HAA ammunition fired, even after the introduction of VT.

Wheels within wheels, as they say :dance: .


Byron
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marcelo_malara
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Re: 5"/25 on shore bombarment

Post by marcelo_malara »

Thanks! Didn´t know all that.
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Re: 5"/25 on shore bombarment

Post by Byron Angel »

marcelo_malara wrote: Tue Sep 27, 2022 11:22 pm Thanks! Didn´t know all that.

De nada. :wink:

Byron
OpanaPointer
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Re: 5"/25 on shore bombarment

Post by OpanaPointer »

Byron Angel wrote: Tue Sep 27, 2022 8:33 pm Hi Opanapointer,
Good question. I assume you are talking land bombardment? I imagine that a VT-fused HE bursting in the air must be pretty visible - especially in the case of targets sheltering in wooded areas. OTOH, I recall reading that VT-fuzed artillery shells themselves, when introduced at the Battle of the Bulge, were found to be devastating against sheltered (i.e. dug-in enemy personnel) - far more so than conventional contact-fuzed HE.

B
Patton said he approved of the shells "with the funny fuse."
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marcelo_malara
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Re: 5"/25 on shore bombarment

Post by marcelo_malara »

Byron Angel wrote: Wed Sep 28, 2022 3:24 am
marcelo_malara wrote: Tue Sep 27, 2022 11:22 pm Thanks! Didn´t know all that.

De nada. :wink:

Byron
:ok: :ok: :ok:
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