Backman Fri Apr 02, 2021 2:45 am
bren_tann wrote:Currently Russia operates 1 Yasen. The second one Kazan should be commissioned in the next few years.
The Yasen is the su 57m of submarines.
They have 5 Akula 3's in service and another handfull coming in from being modernized.
Just because there's 1 Yasen doesn't mean the fleet is a slouch
Yasen lacks pump jet. The upcoming Khabarovsk should be able to go toe to toe with Seawolf / Virginia. In any event, Russia needs 10 Yasen and 10 Khabarovsk in order to be able to challenge America in undersea.
Russia had a Kilo class submarine with a pump jet in 1990.
It was a design choice. But you are sitting here saying that pump jet is superior full stop.
It isn't. If it was, the Yasen would have a pump jet.
First, pump jets don’t necessary mean quieter running. Propeller blade shape is actually more important, reportedly. Second, most common form of a pump jet employed in submarines, the ducted propeller, is most advantageous at lower speeds, about up to 10 knots, and rapidly lose efficiency above that level, requiring putting more power to the propeller, which actually defeats the noise advantage, as more power = more noise generated by the machinery. So the pump jet is best suitable for the somewhat slow-running subs like boomers, and not much so for attack subs
. And, indeed, Russian boomers use pump jets since the project 941 (Typhoon/Akula class), but Yasen trades a somewhat higher noise of the screw for higher efficiency at speed, which allows it to use less power at the same speed. Less power=quieter at that speed.
In submarines design, you pick a speed range, and you pick your quiet level.
BTW, many subs in the same class can have different propellers and therefore are optimized for different missions. The operational depth of the sub has a lot to do with choice also. Water is more compressed at depth so less cavitation anyway.