2S3 "Akatsiya" floatation packages

Due to the 2S3 "Akatsiya's" inability to traverse water obstacles using fording equipment, VNIITransmash was tasked with developing 2 different floatation package kits. One design was based on a hard frame body and the other was a pontoon-style kit, both of which could be mounted and unequipped. VNIITranshmash also carried out model tests using the PST-63M pontoon flotation package. 

Floatation package No.1 mounted on 2nd pre-production 2S3 prototype

Two experimental hard frame body packages were created by VNIITransmash together with СЗТрМ (Sverdlovsk Transport Engineering Plant). The 2nd 2S3 pre-production prototype was retrofitted to equip the aforementioned kit and was tested in 1970. 

The design was made using a hard frame body, which consisted of tubes, mounted to the hull and turret of the vehicle. A rubberized tarp was attached to the frame and mounted to hermetically sealed mounting points. The driver had a special opening in the front of the package but directions were given by the commander of the SPG. The engine was fitted with an elongated exhaust extending slightly above the frame. Two pumps were used to pump out water in cases of leaks. 

The 1st design had the hard frame body go around the entire tank hull. The 2nd design was much smaller and was only mounted in the front of the hull but to provide buoyancy a large cylindrical tank was mounted in the rear of the hull. 

Floatation package No.2

Movement in the water was achieved using track motion. To improve performance, hydrodynamic track guards were mounted in the front.

Floatation package No.2 is being used on a 2S3 at a local water testing facility at VNIITransmash

Both of the packages offered a water cruising speed of 6.5km/h. The 2nd variant was more sought-after due to its lower weight among mounted equipment and generally was easier to equip and de-equip. 

Images scanned by author of blog. 

Taken from: 

1. Боевые машины Уралтрансмаша. Книга третья. Уральский букет. 1966-1989 гг.