"Use of HE vs AP" Topic

I have just started to learn more about the dreadnaught / WWI naval engagements. I have read several sources that comment on the use of HE at longer ranges and the use of AP at shorter ranges for the big guns. As near as I can tell the reason is that at longer ranges, HE was better at punching through the thinner deck plates using a plunging arc and at shorter ranges, AP was better at punching through the belt armor.

Is this the gist of it or is there more?

Trying to understand if in a war game of this type, should the player have the ability to pick ammunition type or is it simply just dictated by range and thus the trajectory of the shell? A decision that any competent Gunnery Officer would make.

Thanks in advance – stay safe.

I would go with B, let the crew decide.

I've never seen a movie or rule set that required a captain to choose the ammo (well, in age of sail ball versus chain, but not for anything post 1900).

So leave it up to your officers and men, they'll serve you creditably.

There should be more to the equation then that. AP will generally do less damage when it penetrates then HE when it penetrates. The difference being IF either one will penetrate. At least that is what I read and why HE was used at longer ranges instead of AP. Also at shorter ranges vs less well armored ships the HE may always be the best bet. So I would allow the player to choose if those variables are taken into account.

From "Devil at the Helm: Naval Warfare 1850- 1906":

"The following types of ammunition may be fired… Spherical Shell… Roundshot… A.P. Solid Shot… A.P. Shell… Common Shell…"

"…Ammunition may only be changed by written order. Such an order will take three moves to be carried out…"

A very highly detailed set of rules; ammunition types available for each gun type are also specified.

I know I keep turning up like a bad penny when WW1 naval combat queries come up. My apologies; I just cannot help myself.

The ammunition outfit of WW1 battleships and battlecruisers included relatively little HE. For example, see HMS Invincible's succession of ammunition outfits (based upon information from NJM Campbell) -

Pre-WW1 peacetime outfit – 80 rounds per gun
24 x APC (black powder filled)
40 x CP (black powder filled)
16 x HE (lyddite filled)

These relative proportions were maintained when the ammunition outfit for wartime was increased to 110 rounds per gun.

With the introduction of 4crh projectiles, the outfit became 110 rounds per gun -
33 x APC (lyddite filled, possibly some black powder filled)
38 x CPC (black powder filled)
39 x HE (lyddite filled)

The ammunition outfit per gun was again altered by mid-1916 to -
44 x APC
33 X CPC
33 X HE

Post-Jutland, it was recommended that the number of HE be reduced to 10 per gun, and later for HE to be eliminated and the ammunition outfit to consist of a half and half mix of APC and CPC. The final ammunition outfit, introduced immediately after WW1, was -
77 x APC (shellite filled)
33 x CPC

As can be seen, heavy caliber HE fell further and further into disfavor as the war progressed. HE was found to be inefficient in the attack of heavily armored warships. DK Brown considered the warhead of the Exocet missile to be approximately equivalent to a 14-inch HE (lyddite filled). Brown stated that its blast effect could hole 4-inches of vertical armor, but with most of the blast expended outside the ship. Although HE could inflict serious damage upon unarmored or lightly armored areas, it could not be relied upon to have much of a disabling effect against a well armored warship

On the other hand, heavy caliber HE was deadly against unarmored or lightly armored targets such as a DD or CL. Such a heavy caliber HE projectile is known to have sunk a destroyer with a single hit.

CPC (British version of SAP) in fact became a quite important projectile in the RN, especially after the flaws of APC (lyddite filled) projectiles became apparent after Jutland.

It is also important to note that HE had next to no intrinsic ability to penetrate anything substantial. It was fuzed to explode immediately upon striking any resistance. Its effect upon the target was measured solely by its blast effect.

FWIW.

B

Hi khanscom,

While I do possess a copy of "Devil at the Helm" (purchased IIRC in 1976 from a little wargame shop next door to my hotel in Chester, England), I never progressed beyond reading through the rules a few times.

How was it to actually play?

B

But didn't HE starts fires topside and the Lyddite create gas that would force German gun crews to abandon their turrets? If your AP rounds would not penetrate in some cases it may have been better to fire HE.

Wolfhag

Well HE is more consistent vs. horizontal armor while AP has to have a certain angle to bite in. I ran a simulation with 9.2" Greenboy AP against it's HE shell and the HE shell has more deck penetration up to 12,000 yards than the AP. The AP and HE is the same at 13,000 yds where AP penetrates more at greater ranges. I'm guessing this pattern is for most guns but the transition range would be different.

While I do possess a copy of "Devil at the Helm" (purchased IIRC in 1976 from a little wargame shop next door to my hotel in Chester, England), I never progressed beyond reading through the rules a few times.

How was it to actually play?

They were written my friend Bob Walker and you'll find me credited along with Clive Essery for "ideas and assistance" in the introduction.

They were designed to period 1860-1905 and they work quite well for that period. Maybe a bit of rivet counting in them. I drop the written orders when I play them today. Each area of a ship has a probability of shot landing there. That area has a number of points based upon armour. Shot does damage depending upon ammunition type and penetration. Once you beat the value for an area you roll for any additional effects.

Are they the fasts playing set out there? No. Considering they were written 42 years they're still good.

"How was it to actually play?"

I never dared to try.

Wolfhag wrote:
"But didn't HE start fires topside and the Lyddite create gas that would force German gun crews to abandon their turrets? If your AP rounds would not penetrate in some cases it may have been better to fire HE."

Mobius wrote:
"Well HE is more consistent vs. horizontal armor while AP has to have a certain angle to bite in. I ran a simulation with 9.2" Greenboy AP against it's HE shell and the HE shell has more deck penetration up to 12,000 yards than the AP. The AP and HE is the same at 13,000 yds where AP penetrates more at greater ranges. I'm guessing this pattern is for most guns but the transition range would be different."
- – -
Dogger Bank and Jutland are the best cases we have to study. HE Lyddite was nose-fuzed and would detonate upon striking any significant resistance; It was very effective when it struck light unarmored or very lightly armored structure, but unlikely to take effect upon the vitals of a heavily armored ship. The only horizontal armor I could visualize falling victim to an HE hit would have been the roof os the secondary casemate battery, usually 1 to 1.5 inches thickness; the lower protective decks would have been highly unlikely to be reached by HE, even at high angles of fall, due to the intervening upper decks that would have set off the fuze. Also, even if the fuze were to have permitted, the shell body was (IMO) probably not really strong enough to remain intact while passing through any sort of heavy structure.

Lyddite was also the explosive filler of British APC at Jutland and there is no question that the explosion of Lyddite in confined spaces produced considerable amounts of noxious gases and fumes that could "incommode" crew in the vicinity of a hit. The duration of inconvenience I would speculate relied upon the condition of the target ship's internal ventilation system and the presence or absence of respirators. Accounts from Bluecher made note of serious fume problems, with some crewmen below decks being asphyxiated as she was being shot to bits.

Fire risk on the part of high explosives like Lyddite and Shimose were considerable, but a great deal depended upon the condition and preparation of the target ship. Japanese Shimose-filled shells created numerous fires upon hitting, but much of this was a function of the high relative flammability of warships of that period – heavy multiple layers of flammable paint, excessive woodwork (see the USS Olympia as an example), wooden and upholstered furniture in the ward rooms and officer cabins and, in the case of the Russian fleet at Tsushima, extra coal stowed all over the ships in unprotected areas. Lessons were drawn by the major navies from the Russo-Japanese war and the fire risk was reduced. There are some interesting stories of some of the more "over the top" efforts by RN ships to clear their ship in the days after the declaration of war – all sorts furniture, bric-a-brac and flammable sundries summarily pitched overboard.

NJM Campbell's book on Jutland has a good summary section, within which known ammunition expenditures by shell type are tabulated. It is interesting to review the relative number of shell types fired (although the targets are unfortunately not easy to determine without a lot of add'l homework.

FWIW.

B

Could HE waterline hits create leaks?

Wolfhag

"Could HE waterline hits create leaks?"

Certainly. In fact, one of the principal objections to the "all-or-nothing" armor concept was that the extremities of the ships were left unprotected and could rely only upon enhanced internal sub-division to limit damage/flooding from hits. Large HE that happened to strike unarmored areas could do serious damage.

From my readings, there were occasions and circumstances when HE might offer an advantage. In the event that your AP cannot defeat the opponent's protection at any range, HE will produce an enhanced damage effect against any "soft" areas that might be struck – Japanese firing against SoDak @ 2nd Guadalcanal, for example – but in such a case the best that can be hoped for is a soft kill. None of the opponent's essential systems are likely to be injured.

I think the proof in the pudding (with the exception of capital ships detailed for shore bombardment duties) is seen in the steady decline of HE in the standard capital ship ammunition outfits over time.

FWIW.

B

British cruisers except for the Town class and Japanese cruisers only had 1" turret and barbette armor so were pretty vulnerable to HE shells.