Needed information on Semi-Armour-Piercing history

[jvollenberg]

Can anyone tell me when the Stampings SAP were initially used on projectiles? Specifically seacoast / 10 inch projectiles?

I am doing some research on these and the stamping SAP is thowing me off. I don't have pictures of it as of right now ... might be able to post some on Monday. But is it found on the base of a 10 inch round originating in the late 1800's here in the US.

Thanks,

Joe

 

[HAZORD]

I have a lot of older reference material, Textbooks from the Naval Academy, Congressional reports, etc. Most date in the early 1900's.

Post your photos and I will start to check through the material.

 

[jvollenberg]

Here is a picture of the marking ... It says 10 IN SAP SHELL

from the research I have gathered so far ... this marking can be fairly old. I just cannot seem to find where and when it originated. I was reading through books from the 1917 / 1918 area and they don't mention it. Only AP rounds. How ever, this round is from the late 1800's.

The plug above it is a fuze well plug for a BD fuze. Unlike the British plugs this oine doesn't have a nomenclature.

Joe

 

[HAZORD]

Joe,

I will start to look through references. In the U.S., artillery development has always followed Navy weapons till after WWI. The need for the Marines to have artillery caused the addition of carriages to Naval guns for land use. The SAP material isn't seen much, whereas the common shell and shrapnel are the ones usually found. Metallurgy was going through a lot of changes as the dreadnought ships were being developed, and the need for stronger armor and better penetration were battling back and forth, everyone looking for harder and tougher armor and the shells to penetrate it.

 

[EODGUY]

Joe,

I'm not sure what is going on with my ability to post on your thread. I typed two nice long messages and both times it told me I didn't have permission to post and the message disappeared. I'll try the condensed version. I am puzzled over your question. It is so simple I never thought of it, yet I am having real trouble finding any kind of answer. I have looked through about 20-25 different documents dated from 1800 to 1979. That includes manuals, reports, books, complete round charts, etc. and NONE of them even mention the term semi-armor piercing associated with projectiles of any caliber. Around the turn of the century the classes were AP shot (solid projectile), AP Shell (cavity projectile) and Deck Piercing. In the 1940 printing of TM 4-205, Coast Artillery Ammunition ,it says that the old AP Shot and AP Shell projectiles were being phased out. Seacoast artillery projectiles 12-inches and above had the two older types being replaced by a more modern design that had an HE base cavity, an angular soft nose cap and over that a long tapered thin metal ogive and it was referred to as just an armor piercing projectile. A design very similar to many modern projectiles. Seacoast artillery projectiles less than 12-inches were being replaced by common steel high explosive shells, so obviously they felt no need for AP projectiles of any type in those calibers. Later manuals have APHE, AP Capped, AP shot, and later, of course, the HVAP family of projectiles. Nowhere in that chain of documents is the term SAP even mentioned that I found.
It is a little far fetched, but I wonder if the SAP could be the government's typical way of reversing words in nomenclatures and it was for Shot, AP or Shell, AP. Dosen't make much sense but other than a category of aircraft bombs I can find no reference to the term Semarmor piercing. I sure hope someone can clear this one up. Bob

 

[jvollenberg]

Thats pretty much what I was finding. Thats why this round is throwing everyone off ... for its time SAP shouldn't be on it. I am begining to wonder if this was some type of experimental round? We know there are 2 gun positions in Oregon (where this round was located). So there were 10 inch positions there. Tomarrow when I get in I wil post the other pics of this round and that might help those looking for things. I am just very confused by the SAP especially since it states 10 IN SAP SHELL.

Joe

 

[HAZORD]

I will add a comment to what Bob has written. During WWII, a number of larger caliber projectiles from 14 inch diameter down had metal straps with bomb lugs bolted around them and fins attached, to be used as deck piercing bombs. I'm thinking this was a way to use up all of the older caliber AP projectiles, and to provide a deck piercing bomb substitute till the different designs could be produced. The U.S. seems to have a habit of keeping old ordnance in storage, and repurposing it for other applications. Perhaps you old projo was stamped to be a SAP bomb, but doesn't have a tail fin or lug straps bolted on.

 

[jvollenberg]

OK a little more on the round that has started this trek ....

here are 3 pics: full round and close ups of the Plug and other marking

The plug is: 35MM
The rotating bands are: 40MM wide
115MM length between spanner holes (center to center)

 

[HAZORD]

Well Joe, first of all, thanks for asking about this. Your request caused me to research through a number of books where I learned a lot, and here is the result:

Started with the oldest and worked forward. "The Annual Report of the Chief of Ordnance to the Secretary of War" in 1887 was covering minor improvements, but they didn't have an explosive to use in an armor piercing projo, and they didn't have a decent projectile due to lack of decent metallurgy. The current trend was to perfect the Dynamite Gun.

The "Textbook of Ordnance and Gunnery" for West Point from 1896 describes some forged Ap projectiles and "Deck Piercing" projectiles made from cast iron. Their Metallurgy was still lacking.

By 1905, the "Textbook of Ordnance and Gunnery" from the Naval Academy had what you are looking for. Armor metallurgy had progressed and was followed by Armor Piercing Projectile Metallurgy. I have attached an excerpts from this manual that defines Semi Armor Piercing as a substitute name for the Forged steel Common projectile, to be used for deck piercing.

The 1921 edition of "Naval Ordnance" from the Naval Academy refers to Semi armor piercing as a projectile type used by other nations. The interesting thing here, is that the U.S. now calls the projectile a Class B projectile, as it is produced to penetrate "Class B" armor, which is the lesser grade of armor used for deck plates. I have attached excerpts from this manual with a projo labeled CL. B and the description.

The 1934 edition of "Naval Ordnance" had no mention of semi armor piercing, and the Class B projectile had disappeared. Common projectiles were still an economy projo, and the Bombardment projo had made its debut.

Other books say that as of 1917, Common projectiles were no longer produced in calibers larger than 5 inch.

So, in conclusion, semi armor piercing was a term in use from early 1900 up to 1921, but your projo would have been produced before 1917.

 

[2pounder]

The British handbook on ammunition admiralty publication makes reference to Semi Armour Piering as a base fuzed shell whose function comes between HEP and AP. typical would be a capped common pointed shell but does not give any idea what period this was used over.