Jump to content

"2in Bomb Thrower" and variants...


Recommended Posts

"2in Bomb Thrower" and variants...

 

Looking around the web, there appear to be the following variants:

 

2in Bomb Thower Mk1 & Mk1A

2in Mortar Mk3

 

All are of the same basic construction, the following pics have been acquired from the web/museum/private sources.

 

2in Bomb Thrower Mk1/Mk1A

 

BT-2in Mk1 - Diagram.jpg

BT-2in-Mk1 - FR.JPG

 

2in Mortar Mk3

 

2in Mortar M3 - Diagram.jpg

2in Mortar M3 - NL.jpg

2in Mortar M3 - IWM.jpg

2in Mortar M3 - UK.JPG

 

So... questions therefore.

 

Which came first

Did they fire the standard 2in Mortar Smoke Bomb, or something modified.

How effective were they

Did the valve mechanism really affect the distance the bomb travelled

Could they be used to fire the HE bomb

What impact did venting the exhaust gas into the turret have

 

Anyone know?

 

Cheers

 

Tim

Edited by Packhow75
Attachment issue
Link to post
Share on other sites

The 2" Mortar Mk3 is not a Mk3 but an M3, a US built copy of the British BT.

 

The proper ammunition was marked 2" BT so presumably different to the standard infantry smoke round. Not sure if it could have fired HE rounds, they may have had a heavier propelling charge and HE was not issued to tanks anyway.

 

There is a pipe that fits on the threaded boss in Cromwell that vents excess propellant gases outside the vehicle, not used in Sherman however. Come to think of it, I'm not sure the valve is used in Sherman installations anyway, will have to check the manuals.

Link to post
Share on other sites
The 2" Mortar Mk3 is not a Mk3 but an M3, a US built copy of the British BT.

 

Adrian

 

Oops... basic reading error!

 

Be interesting to see what you come up with.

 

It seems a bit mad to me to have the gas simply vent into the turret.

 

Do you have any pictures of the smoke bombs?

 

Cheers

 

Tim

Link to post
Share on other sites

Ok, there were three models fitted to Shermans.

 

Mk. IA

Mk. IA*

Mk. II

 

The IA, firing an 18 grain ballistite cartridge had a fixed range of approx 150 yards.

 

The IA* was developed to give a variable range. This was achieved by fitting the adjustable gas release valve in the chamber and using a 55 grain cartridge. It is a modification of the Mk IA rather than a new design.

Early models had the valve retained by a Jubilee clip and these were restricted to using the 18 grain charge. Later models had the valve retained by a U bolt and could use the full charge.

In Sherman, the vented gasses were released into the turret where ''they have no ill effects on the crew''. Quite what the crews concerned thought about that is not revealed!

 

As mentioned, in Cromwell, gasses were vented to the outside via a pipe.

 

The Mk II, also known as the Campbell bomb thrower, was a new design that used an adjustable concentric sleeve (3) to set the range and gases were vented coaxially up the barrel.

BTII.jpg

 

There were two types of bomb used, the Mk I which was filled with HCE. This smoked from firing, hence leaving a trail back to the tank. It burned for 1 1/4 minutes. Early bombs had aluminium tails and could only use the 18 grain cartridge, later bombs used Mazak or steel fins and could use the 55 grain cartridge.

 

The Mk III bomb was filled with white phosphorous and was fitted with a no 151 percussion fuze so only started producing smoke upon impact.

BT bombs.jpg

Edited by Adrian Barrell
Link to post
Share on other sites

Adrian

 

Very interesting - thanks.

 

I think I'd prefer a smoke bomb which smokes on impact rather than one which leaves a smoke trail back to the tank... but then I suppose you'd hope the enemy aren't close enough to see the smoke trail!

 

Cheers

 

Tim

Link to post
Share on other sites
Adrian

 

Very interesting - thanks.

 

I think I'd prefer a smoke bomb which smokes on impact rather than one which leaves a smoke trail back to the tank... but then I suppose you'd hope the enemy aren't close enough to see the smoke trail!

 

Cheers

 

Tim

Slightly off topic, so apologies, but I'm wondering whether anyone has tried using the smoke launchers on their armored vehicle. I had to demil them on my Saracen to ship it to USA, and I don't have any of the actual smokes anyway. But curious how they would work in the theoretical world. I guess they are all electrically activated, anyone actually fire them?? And is the "ammo" available/legal to purchase?

Link to post
Share on other sites
Slightly off topic, so apologies, but I'm wondering whether anyone has tried using the smoke launchers on their armored vehicle. I had to demil them on my Saracen to ship it to USA, and I don't have any of the actual smokes anyway. But curious how they would work in the theoretical world. I guess they are all electrically activated, anyone actually fire them?? And is the "ammo" available/legal to purchase?

 

I was led to believe that the smoke dischargers on the Saracen can also be used to launch grenades (60mm?) and therefore are required to be deact in the UK.

 

Hopefully someone will confirm if this is correct, or not?

 

Tim

Link to post
Share on other sites
I was led to believe that the smoke dischargers on the Saracen can also be used to launch grenades (60mm?) and therefore are required to be deact in the UK.

 

Hopefully someone will confirm if this is correct, or not?

 

Tim

The shop restoring my Saracen told me they hooked up the electric wires, but I don't know if whatever triggers the firing mechanism was actually present.

I had to deactivate the smoke launchers per ATF (Alcohol, Tobacco, Firearms) Form 6 form, which allows conditional approval to import Saracen into USA. One of the conditions was that smoke tubes be bored with hole perpendicular to tube and equal to tube's diameter. So it's totally unusable. I was just curious if the unmolested launchers were operational and if anyone ever used them!

Link to post
Share on other sites
  • 3 weeks later...

I have a number of vehicles with the deactivated post war smoke dischargers and can confirm that a couple of years ago, the Association of Chief Officers of Police decided that they were pyrotechnic dischargers and NOT firearms so there was no need to have had them deactivated! I think that this decision was based on the fact that the tubes themselves have absolutely no mechanism being just a tube with a small hole at the back. They work by a small charge being placed in the barrel with wires going out of the hole in the back, these connect to terminals and when 24v is applied, the charge ignites. There is a tapered grommet on the wires to form a seal in the wiring hole.The charge throws out a smoke grenade which has been placed in the barrel with the handle inside the tube. You have to pull the pin after placing it in the barrel but the grenade does not set off because the handle is held in place until it leaves the barrel. Charges could be made up easily enough and live smoke grenades can be bought but I would consider that placing them together does make it into a dischargeable illegal firearm (like putting ammonia and a water pistol together) so risks 5 years in prison. The case with the 2" and the 4" weapons is different however. Both are sealed at the breech end when loaded and have firing mechanisms. As both have barrels less than 24" long, they are a banned type of weapon (similar to full calibre cartridge firing pistols) and if not deactivated, prison would be unavoidable, even if used only for blanks.

I was told by an ex National Serviceman that any type of smoke discharger, loaded with bird shot, rock salt or gravel was wonderful at clearing riots, particularly in the Middle East while the UK was mandated to "keep the peace" there.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...