Soviet never-built Submarine designs

[darthpanda]

Project 673

[thegrumpykestrel]

Awesome! By sheer coincidence I read about this just yesterday, nice to see it done here

[heuhen]

it's a weird f***** isn't it

interesting drawing btw

[Hood]

A great addition, I can't wait to see what gems turn up in this thread.

[AF92]

It must have had a crazy underwater speed

[heuhen]

It must have had a crazy underwater speed

Numbers I have seen on the internett suggest a top speed of 40 knots, but how fast it would have been in reality...? Although Project 705K ALFA Class could do 41 knots and it used many of the design features from project 673. (Project 661 Anchar / Papa class are recorded at 44.7 knots as the world fastest submarine.)

[AF92]

It must have had a crazy underwater speed

Numbers I have seen on the internett suggest a top speed of 40 knots, but how fast it would have been in reality...? Although Project 705K ALFA Class could do 41 knots and it used many of the design features from project 673. (Project 661 Anchar / Papa class are recorded at 44.7 knots as the world fastest submarine.)

Propulsion is another matter to consider. Both classes had the same OK-550 or BM-40A (on Alfa) reactors that produce 155 Mwt of electricity for 40.000 hp engine performance. I can say that Pr.673 would be much faster (and maneuvrable) as it was designed to be %25 smaller than Alfa class.

[Hood]

My main concern would be stability at high speeds without the stabilising effect of a conning tower.

[heuhen]

My main concern would be stability at high speeds without the stabilising effect of a conning tower.

And knowing back then they did mostly a: "fail and error, testing"... Those reports would be fun to read.

[erik_t]

My main concern would be stability at high speeds without the stabilising effect of a conning tower.

If anything, underwater stability and control ought to be better, not worse. Stability in pitch will obviously be unaffected. Stability and controllability in yaw should improve -- since the sail on nearly every submarine is well forward of the center of pressure, a sail is a destabilizing element. Of course, you could then reduce the size of the stern control surfaces to reduce drag, and indeed this design seems to have unusually small vertical surfaces.

It is in roll that the removal of the sail would have the most pronounced effect. This is most apparent on a US-style sail, which is a tall, wing-shaped structure. Because it is forward of the center of rotation of the boat, when the submarine yaws, the sail is at an angle of attack to the local flow. Because it is above and not below the hull, whatever lift the sail generates translates directly into a rolling moment which (IIRC) rolls the top of the sail outward during a turn. This effect would be less pronounced on a Soviet-style low 'pimple' of a sail, but it would be non-zero.

Submarine designers have been itching to get rid of the sail for almost as long as submarines have operated mostly underwater. Operators having been resisting this, for very understandable reasons, for just as long. Still, it seems conceivable that the Virginias will be the last USN attack boats with a sail, just as it seemed that the Seawolf might be the last, and the 688s the last, and even Sturgeon the last. Wave your hand to give Rickover just a little bit less influence in the late 60s and early 70s, and Los Angeles might have looked like this...