"April 5th, 1941
Tactical-technical characteristics for design and production of an explosive delivery and deployment device for the T-34
- The explosive delivery and deployment device for the T-34 tank is designed to demolish various bunker type fortifications, which can only be approached under the protection of armour, and destruction of anti-tank fortifications.
- The explosive delivery and deployment device must be removable and suitable for installation on a mass production tank, by field workshops if necessary.The following changes are allowed by the GABTU, on the condition that they do not impede the tank's function:
- Attachment or welding of lugs on the inside or outside of the tank hull, in locations where they do not impede service.
The size of lugs can be no more than 150x150 mm, with no more than 1-2 lugs per square meter of hull. The form of the lug can be oval or square with truncated corners. The lugs can be attached with shellproof blunt bolts. The lugs must be welded according to standards, with austenite electrodes. The distance between two parallel weld seams must be no less than 100 mm.
- Drilling of holes up to 35 mm in diameter. The number of holes can be up to 1-2 per square meter of hull, with no less than 200-250 mm between holes.
When the device is not installed, the holes must be covered with caps, equivalent in resistance to the hull, which come standard with the device.
When designing the hull, the first aim must be to retain the hull as is (use existing openings), then to use lugs whenever possible.
- The explosives and fuse must be protected with armour during transport, equivalent to the tank's main armour in protection.
- The mass of explosives required to demolish a bunker is 300 kg.It must be possible to transport and deploy smaller charges, 50 kg each, designed to destroy dugouts, anti-tank fortifications (ditches, etc), and log barricades. The number of charges carried is 4-5.
- The shape, attachment, and delivery conditions must ensure that the explosive charge ends up right next to the wall of the bunker in the optimal position.When blasting openings in anti-tank ditches, the device must allow placement of charges on the ground one meter away from the edge of the ditch.It must be possible to place a charge on a 45 degree slope, up to one meter in height.
- Controlling the deployment of the charge must be done by one person, from inside the tank.
- The position of the device and charges on the tank must not impede observation or firing from the tank, and must not reduce the tank's maneuverability.
- The charge's armoured cover must remain on the tank after deployment.
- The fuse must go off as soon as the charge is deployed. The charge will detonate five minutes after deployment.It must be possible to increase the fuse length to 7 and 10 minutes. The timer will be set when the charge is loaded.
- The fuse must be simple in design, reliable, and produced from available components.
- Working with the charges and fuses during installation and removal must be safe for personnel with average training.
- The addition of the device must not make servicing the tank (fueling, oiling, etc), entering the tank, or driving the tank more difficult.
- The tank's crew must be able to install the explosive charges and armoured cover on the tank with the aid of simple equipment, designed for this purpose, which will be included with the device.
- The total mass of the explosive charge, armour, and device must not exceed 1000 kg.
- It must be possible to transport the charge inside the tank and still be able to place it on the target.
These tactical-technical requirements serve as the foundation of design and production of the prototype. Designers are allowed to make changes that improve the function of the device, but only with the permission of the GABTU. Tactical-technical characteristics are subject to review and approval when the design is presented.
Chief of the 3rd Department of the BTU, Military Engineer 1st Class, Afonin
Chief of the 6th Section of the 3rd Department of the BTU, Major Kovalev"
Similar requirements were composed for the KV-1 tank, except the KV's device would carry 600 kg of explosives (or 8-10 50 kg charges), and its mass was limited to 1600 kg.