[foldr]

I believe submarines navigate long distances using INS. I don’t know how accurate it is, or how often they have to make corrections using other data. But ballistic missile submarines can’t really use active sonar or surface with any frequency, so I’m not sure what other method they’d use.

[simne]

I talked with captain of submarine. He said, in real life navigation was not reliable, so they have to go to surface and make adjustments with some classic navigation - radio beacons and star navigation.

And civilian education now close to forgot star navigation, but navy still train people to navigate with stars and learn Morse code.

https://news.ycombinator.com/item?id=43319923

[simne]

> ballistic missile submarines can’t really use active sonar or surface with any frequency

Detect semi-surfaced submarine at night is really hard, if don't have intelligence data that it will surface on some non-random position.

From experience of Ukrainian war, my country have success with eliminating surface military ships, because have constantly monitoring their moves with satellites, but I cannot remember any case when semi-surfaced submarine was hit.

[foldr]

Are they not easy to detect on radar? Even during WWII, radar got good enough to detect submarine periscopes. It's hard to imagine that a partially surfaced submarine wouldn't have a significant radar return. That doesn't mean that they're easy to detect at long ranges, but I would have thought that partially surfacing or raising a periscope would be a significant risk to a submarine if the enemy knew its rough location.

At a guess, Ukraine probably can't deploy naval assets with powerful radar close enough to where Russian subs are operating. But an adversary with a more powerful navy might be able to.

[simne]

> if the enemy knew its rough location

In these words you hit bull eye.

During WWII, submarines was just very special type of boat. You could check wikipedia about German u-boats - exist about TEN subtypes, from which only latest types have really significant underwater range, but all others was extremely limited in underwater activity.

But, surface ships of that time was even more limited, many could not achieve even half of surface speed of u-boat, so become easy prey.

But if you will try to find some artificial object on sea surface, that is really hard question. Just because sea is huge, so you need to check extremely large space in short time.

Radars are better to spot artificial object on sea surface than visual, just because radar easier to automate. But nothing more. Radar is also have problem of square distance, very similar to visual. So, as it is hard to spot partially surfaced submarine visually, it also hard to spot such sub with radar, because much less part will be on surface, so radar will have much less signal to detect.

Periscope size is nearly undetectable on surface, if it used carefully, just outside detection range of radar.

So, to conclude, Ukraine problem is, we cannot detect partially surfaced submarines on open sea, but they could fire missiles. Fortunately, Russians have very few submarines on Black sea, and after they was hit at harbors, their usage become very limited.

[foldr]

> But, surface ships of that time was even more limited, many could not achieve even half of surface speed of u-boat, so become easy prey.

Agree with most of what you said, but U-boats generally had top surface speeds under 20 knots and were thus slower on the surface than most naval vessels of the time. They could certainly move faster than most convoys, but they couldn’t outrun pursuing destroyers or corvettes.

[simne]

> slower on the surface than most naval vessels of the time

That is point. I'm not agree about most, but will be agree if you say about many.

> they couldn’t outrun pursuing destroyers or corvettes

But problem was, navy have so huge deficit of ships, so some convoys was run without naval support.

Sure, if all convoys was supported with fastest ships with best commands, u-boats will be no problem anymore, and as I understand, once this was happen.

[crote]

A big issue during WWII is that the submarines were trying to find and approach the ships in order to sink them - and the ships in turn were looking out for the submarines. The submarine is forced to be close to ships equipped with radar.

Ballistic missile submarines are a completely different story. They aren't chasing anyone. Their entire goal is to be unpredictable and stay hidden, so if there's anyone with a radar around they are just going to keep quiet and move somewhere else.

Finding a sub prowling a shipping route is quite doable. Finding a sub in the middle of the Pacific Ocean? Not a chance.

[simne]

I must admit, I agree with nearly all you said. Problem is that Ukraine was weak, and nearly without navy, and civilian ships was unable to resist to Russian navy. And Ukrainian export was blocked, as civilian ships fear to run within range of fire of Russian navy.

When Ukraine got enough weapons to force Russian ships to stay at distance, situation changed dramatically, so export was unblocked.

I think, very similar things happen during WWII.

This is not about only submarines, this is about superiority.

[maratc]

> Are they not easy to detect on radar? Even during WWII, radar got good enough to detect submarine periscopes.

They are, if you can get your radar on top of the periscope, e.g. mounted on a plane that flies above the sea.