Battleships firing HESH?

goose

ACCESS: Restricted
Joined
14 July 2010
Messages
29
Reaction score
5
I wonder what the effect of an 11-inch High Explosive Squash Head (HESH) round would be on a ship? I'm sure that the shear quantity of explosive would be spectacular and cause great damage to 'soft' structures directly as well as indirectly due to shock waves. Also a near miss into the sea could have an effect if detonated as water transmits shock quite well. If the round hit armour it would cause spalling on the other side-shedding people, equipment etc . Would they be more effective than the heavy armour-piercing shells that Battleships fired? I welcome any comments.
 
Perhaps, given the terminal velocity involved at impact, it would be high-explosive splatter head rather than high-explosive squash head. ie ineffective.

But what would I know about ships.
Chris
 
I'd be suprised if a HESH round could survive launch from a typical naval gun - they have pretty thin shell walls to ensure that the plastic explosive can spread out properly on impact. At the velocities needed to achieve useful ranges at sea, I'd expect to see rounds breaking up in the barrel.

There were high explosive rounds for battlehip guns, called High Capacity shells. Even these had quite small explosive fills (<10%), due to the need for thick shell walls just to survive the launch forces.
 
A quick look on the internet reveals that the 15inch naval gun fired its shell at 749m/s. The 105mm L7 tank gun fired its HESH at 737m/s. Practically identical, that suggests that a naval HESH shell would work as advertised & achieve similar range to conventional rounds. The low HE of the conventional naval ammunition may be a result of the technology of the time. My main question is what would be more effective, an armour piercing shell exploding inside the warship or a HESH against its outside?
 
The success of HESH rounds depends on the ability to transmit the shock wave through the armor and cause spalling on the inside of your target.


I see two problems with using HESH:


1. Battleship armor is layered which would inhibit the shock wave effect. Any spalling would likely be between armor layers and would therefore be ineffective.


2. Ships are compartmentalized and any spalling that did get through would have difficulty penetrating to sensitive areas and areas like the magazines have their own armor layers.


As you can see from the following cross-section, the armor is multi-layered and actually designed to stop spalling (slintering).


IowaSideArmor_zps66dc51bc.jpg
 
goose said:
Would they be more effective than the heavy armour-piercing shells that Battleships fired? I welcome any comments.

Possibly. However a shaped charge warhead would be even more effective. However the fact there are no shaped charge warhead big naval rounds developed is closely linked to why there are no more big gun battleships. While WWII demonstrated that scarce naval funding was much better spent on aircraft carriers than battleships it also demonstrated that gun ships were not a good idea in the face of shaped charge warheads. Loading a ship with highly explosive propellant charges in the face of shaped charge warheads that can punch a molten jet through the armour and into the magazine creating a catastrophic chain explosion was not very appealing.
 
SpudmanWP said:
I see two problems with using HESH:


1. Battleship armor is layered which would inhibit the shock wave effect. Any spalling would likely be between armor layers and would therefore be ineffective.


2. Ships are compartmentalized and any spalling that did get through would have difficulty penetrating to sensitive areas and areas like the magazines have their own armor layers.


As you can see from the following cross-section, the armor is multi-layered and actually designed to stop spalling (slintering).

The natural and designed in layering of a multi deck, multi compartment warship would not be so effective against a ship sized charge of a HESH warhead. The armouring of a battleship is designed to defeat spalling from the armour created by impacts of kinetic penetrators. A HESH warhead of similar size would create far larger and far more energetic spalling. Many of these splinters may have the size and velocity to penetrate further inboard layers of armour to reach the protected areas of the magazine and propulsion units.

Further the thing about using explosive energy for penetration of armour (HESH, HEAT) is you are no longer dependent on velocity for your penetration capability. So you don’t need to shoot relatively small artillery shells that can be launched by feasible guns. Gliding bombs, missiles, etc with low terminal velocities are more than acceptable allowing for much larger warheads. The first versions of the Soviet Styx anti ship missile, from back in an era when the NATO allies still had quite a few armoured gun boats in service, was equipped with a 500 kg (1,100 lbs) HEAT warhead.
 
I think we should look upon this not as a reinvention of AP projectiles for battleship main guns but rather as a means to add significant AP capability to what is otherwise basically a HE shell.
HESH "penetration" is roughly 1.2x Shell diameter.

HESH also does significantly more shock damage to structures than regular HE.
 
I read somewhere that all Soviet big aircraft carrier killer missiles eg.: P500, CH22 etc. has some form of HEAT warhead. Major problem was to survive Mach 5 impact, while deliver big explosion and Soviet Union decide to go for HEAT effect triggered by radar fuse and explosion 1-2 meters from the hull of attacked ship.
 
I read somewhere that all Soviet big aircraft carrier killer missiles eg.: P500, CH22 etc. has some form of HEAT warhead. Major problem was to survive Mach 5 impact, while deliver big explosion and Soviet Union decide to go for HEAT effect triggered by radar fuse and explosion 1-2 meters from the hull of attacked ship.

To be exact, they use combined high explosive/shaped charge warhead. A large HE with shaping cavity in front (pointing at downward angle). The idea was, that when missile hit enemy ship - usually from shallow dive - the jet would penetrate deep into the hull, affecting machinery, ammo magazines, command posts, while the blast wave and fragments would damage the upper hull and superstructure.

For example, the KSR-2 missile:

1652720947562.png
 
Large naval rounds, be they AP or HE, are best when they can penetrate a lot of ship, and not necessarily the armored portions. Wrecking a larger number of compartments and causing flooding then progressive flooding is preferable to an HE detonation on impact. AP rounds, even if they don't detonate, create a considerable amount of fragmentation along their path through the ship.
It really makes no sense to use HEAP on a ship as that would limit the damage to the point of impact likely reducing the amount of damage the round does.
 
Large naval rounds, be they AP or HE, are best when they can penetrate a lot of ship, and not necessarily the armored portions. Wrecking a larger number of compartments and causing flooding then progressive flooding is preferable to an HE detonation on impact. AP rounds, even if they don't detonate, create a considerable amount of fragmentation along their path through the ship.
If you're using HE for anti-ship work, the way to do it is to fit the fuze to the base of the shell rather than the tip. That way it penetrates soft structure before detonation, rather than on contact.

Anti-ship missiles, of course, do some fairly sophisticated things with shaped charges, which are tuned differently than HEAT rounds. That has to do with the constructional differences between ships and tanks; I don't think I need to tell anyone that they are two very different things! Those same constructional differences make HESH a bit pointless.

About the only way I can think that HESH might be a useful round for warships is if you were doing a harbour raid and wanted to perform direct fire against concrete structures. But that application is so niche as to not be worth thinking about.
 
If I recall correctly, Japanese during WW2 experimented with sort-of HESH munition: aerial bomb with rubber spherical nose, filled with powdered explosive and equipped with delay fuze. The idea was that rubber nose would squash upon impact of target, thus increasing contact area. Those bombs were envisioned as anti-fortification weapon, though, albeit anti-ship use was also considered.
 
This is what a general purpose 1000 lbs. WW 2 era bomb could do to a ship.

1652811447285.png

1652811533999.png

In both cases, the bomb failed to penetrate any armored portion of the ship but pretty wrecked the bow and stern areas in a single hit. If the ship were at sea, massive flooding would have occurred due to wave action followed by progressive flooding as water entered the ship. So, I see no reason for a HESH round.
 
With guns against armored ships, there are basically two approaches:
  1. Penetrate the armor and explode a charge, even a relatively small one, deep inside the ship.

  2. Attack the "outside" of the ship causing enormous damage to the unarmored (or just lightly armored) parts and, if you're lucky, starting fires. This is analogous to trying to get a mission kill on a tank with artillery not by penetrating the armor, but by destroying vision blocks, fire control equipment, running gear, etc., all of which require expensive and time consuming repairs.
The first option is the one that sometimes produces catastrophic damage, e.g., HMS Hood, and seems to work best (as per one of T. A. Gardner's posts and I think every navy's practice). HESH may penetrate an outer layer of armor (either literally or via spalling), but the combination of layered armor and critical spaces (e.g., ammunition and power plant) being deep in the ship seem to make HESH unlikely to produce the effects we're looking for in Option 1.

But option 1 is not always available. There may be situations where the combination of the enemy's armor and the range and the power of your own guns takes it off the table. Then the question becomes what's the optimal ammunition choice for Option 2: HESH, HE, or something else?

HE damages not just by blast but also by fragmentation, so it's very much aligned with Option 2 and it has a bonus of being much easier to spot fall of shot at long range than it is with an AP round. Again T. A. Gardner has already posted a good example of HE's work.

HESH might have the advantage of being more destructive to the outer armor layer than HE while still doing a great deal of blast damage. This is traded off for less fragmentation. It's hard to guess where that tradeoff winds up, but I suspect that, given the blast hardening anything outside the armor envelope of a battleship has to have, just to survive the muzzle blast of a main gun salvo, the added penetration of fragments might be important.

I'd note that neither HE nor HESH is designed to start fires, which are particularly dangerous to ships, so I'd wonder if some sort of very large high explosive - incendiary round might have been do-able, but that would probably be an over-specialized round, if it were possible at all.
 
In pure theory, HESH might be efficient if it hit outside armored belt, shattering the plate and creating massive hole for flooding. Problem is, by WW2 outer belts were relatively rare...
 
This is what a general purpose 1000 lbs. WW 2 era bomb could do to a ship.

View attachment 678086

View attachment 678087

In both cases, the bomb failed to penetrate any armored portion of the ship but pretty wrecked the bow and stern areas in a single hit. If the ship were at sea, massive flooding would have occurred due to wave action followed by progressive flooding as water entered the ship. So, I see no reason for a HESH round.
That's not from bombs. That's damage from the USS Massachusetts. This is the Jean Bart and photos after the Battle of Casablanca.
 
Back
Top Bottom