Why did the Soviets put so much emphasis on amphibious, sea-land warfare even before WW2 despite being primarily a land warfare nation?

by 2012Jesusdies

USSR developed and produced one of the first amphibious tank, T-37A, 1200 of them, T-38 would be 1340. These are pretty big numbers for pre-war tanks, for amphibious tanks, especially so. Why would they make these? They wouldn't be completely useless in a war, but I see very limited use as the USSR. Their most likely and powerful enemies pre WW2: Japan, they can't beat the IJN to land these tanks anyways, Germany, they also can't beat the Kriegsmarine and even if KM is neutralized, would opening a new front in North Germany really be that great of a decision? If it was for crossing rivers, they don't seem to have been actually used for that role very often.

If it was USA, Japan or UK, primarily naval powers investing heavily into such tanks, I'd understand, but for USSR? During the Cold War as well, they seem to have invested heavily into amphibious IFV and recon vehicles. The Soviet surface naval capability edge hadn't improved on a grand scale over NATO, so what gives?

wotan_weevil

Why did the Soviets put so much emphasis on amphibious, sea-land warfare

The various Soviet amphibious tanks and armoured cars were primarily reconnaissance vehicles. In this role, it's very useful to be able to cross rivers and swamps. Using them in river-crossing assaults was possible, but this wasn't their main purpose. They sacrificed protection to keep their weight down to the point where they could float, which was made worse by the large hull required for buoyancy (which meant that the armour was spread over a larger surface area). If they were the only armour available to support the infantry on the far side of the river, they would be better than nothing. The post-WWII PT-76 was used by Soviet and Warsaw Pact naval infantry (i.e., marines) and coastal defence units, but the vast majority were used by reconnaissance units. The earlier Soviet amphibious tanks were almost exclusively reconnaissance vehicles (and since so many were lost during Operation Barbarossa, they didn't have enough, and used many non-amphibians (and the US-supplied Ford GPA amphibious jeep or "seep" - the US decided that they weren't very good, and gave many to the Soviets)).

Cold War Soviet river-crossing doctrine was to cross straight from the march, as quickly as possible. This assumed that opposition would be fairly light. The main crossing would be made by amphibious APCs, and if opposition was light enough, the APCs would continue moving forward without the infantry dismounting (just firing on the move from their vehicles). The actual crossing would be protected by smoke, and artillery or tank fire from the original bank. When a bridgehead was secured, tanks would cross by fording if possible, and ferries and/or snorkeling otherwise. (Amphibious tanks are useful for engineering reconnaissance units to find suitable fording places.) The problem with trying to get amphibious tanks across as the first tanks is that they are very vulnerable, and they don't play a major role in Soviet doctrine for river-crossing assaults.

Other notable amphibious vehicles were the amphibious self-propelled 122mm howitzer and the amphibious wheeled carrier for the SA-8 SAM. The goal of these vehicles was to be able to keep up with the infantry (who were using amphibious APCs), rather than having to wait for ferries or bridges.

Most of the combat use of Soviet (or Soviet-supplied) amphibious tanks has been as light tanks, not making use of their amphibious capabilities. In this role, they have suffered from their very light armour, but the PT-76 at least had the benefit of a reasonable effective gun. The most successful user of the PT-76 as a combat vehicle was India, in whose hands they performed well against Pakistani light tanks in 1971 (the opposing tank was the M24 Chaffee, with a somewhat inferior gun and little more armour than the PT-76).

For more on Cold War Soviet doctrine, see: