Type 212 sprint endurence?

[speed150mph]

okay so im in a debate with a buddy over Nuclear vs Diesel subs. Im a nuke supporter, and hes for the diesels.

and of course I had to bring up the range idea, which is the logical advantage over a diesel, and he said that with AIP a diesel had enough range to perform any task. I countered with a scenario...

I set it up that there was an enemy battlegroup inbound towards a friendly target, and you are a distance away. you have to intercept the enemy battlegroup before they get in range of their target.

so I know that on AIP they can stay submerged for up to 2 weeks and travel 3000 nm running at 4 knots. but what would be the maximum range of a type 212 sub running on AIP at flank speed?

[magicstix]

I always find these debates amusing, as none of them have enough info to go on. The capabilities of both types of submarines are closely held secrets, so an internet argument will invariably come out wrong. :P

[Paulebaer1979]

But what would be the maximum range of a type 212 sub running on AIP at flank speed?

It´s nearly none. Because the AIP-system is not strong enough to produce as much power which is needed for flank speed.

All subs without nuclear power have this problem. They are very quiet but for this the have to relaod their batteries regularly. This can be done by diesel (surfaced or with snorkel) or by the AIP at low speed.

It´s a question of the taktik from the navy if they use nuclear or diesel/AIP-subs.

[ikalugin]

The easy answer for this - nuclear submarines are better at operating in the deep seas, due to the fact that their speed and underwater endurance are not limited (well you can run out of food but this is about it).

Conventional submarines are good at operating in shalow waters, as they can crawl quitely, however AIP submarines did solve some of the issues conventional submarines had (ie the need to conduct a noisy battery recharge on PD).

[Paulebaer1979]

Conventional submarines are good at operating in shalow waters.

Yes. That´s right. Both, class 206a and 212, can operate submerged in waters with a depth of 18 metres. Try this with a LA-class :har:

Conventional subs are designed to prtoect the coastline. Nuclear subs are designed to protect the whole ocean (or try it).

The biggest problem of a nuclear powered sub ist to kepp the reactor cool and save. In 2002 my sub did an exercise against a LA-class (fresh out of the shipyard after refresh). We won 30:1. Our commanding officer decided to snorkel during exercise - batteries were at 60% at that moment. Above 5kn nearly all nuclear subs make noise for cooling it´s reactor. conventional subs are designed to be quiet up to 10kn - but they make noise when snorkeling if they don´t have an AIP-system.

[ETR3(SS)]

The biggest setback for a nuclear powered submarine is the reactor coolant pumps, they make the most noise of anything on the boat. That's why the Ohio class had a natural circulation reactor, the S8G.

[Hinrich Schwab]

I always find these debates amusing, as none of them have enough info to go on. The capabilities of both types of submarines are closely held secrets, so an internet argument will invariably come out wrong. :P

Agreed. The only thing debatable are those issues that are publicly known. Nuke boats make constant noise with certain cooling systems. Diesels make noise during a battery charge and AIP boats have very expensive fuel cells to replace.

[magicstix]

Agreed. The only thing debatable are those issues that are publicly known. Nuke boats make constant noise with certain cooling systems. Diesels make noise during a battery charge and AIP boats have very expensive fuel cells to replace.

Just because a nuke has a reactor doesn't mean it needs a coolant pump, and just because it has a coolant pump doesn't mean you can hear said pump outside of the hull. ;P

[ikalugin]

Most modern (late 3rd and 4th generation) pressuriesed water-water reactors have the ability to operate under natural circulation when on low power.

In liquid metal reactors you could use magnetic pumps which do not have any moving parts, thus the only noise you make is the flow noise (which is more or less constant in this case and can be actively cancelled out).

Another means of reducing the noise of a nuclear submarine is to detach the turbines from the propulsor, for example by using electric transmission. Partially this is done on the pr.885 for example - when on low speed it would travel under the electric motor.

[ETR3(SS)]

Just because a nuke has a reactor doesn't mean it needs a coolant pump, and just because it has a coolant pump doesn't mean you can hear said pump outside of the hull. ;P See quote below.

The biggest setback for a nuclear powered submarine is the reactor coolant pumps, they make the most noise of anything on the boat. That's why the Ohio class had a natural circulation reactor, the S8G.

[magicstix]

Getting back to the original question in the post:

The type 212 has a 1.7 MW Siemens electric motor. This is what's going to be driving your prop.

If we make the reasonable assumption that flank speed on a 212 will take pretty close to the max output of this electric motor, for our purposes, let's say 1.5 MW, then we need to provide that power somehow.

The first way would be with batteries. Well there's very little info on how much battery power the 212 has, so we can't say much about how long a charged battery would last at flank speed.

We do know, however, that the fuel cells can directly drive the motor, so let's look at that.

Most type 212s have 2 Siemens PEM fuel cells rated for 120 kW each, so we have roughly 240 kW to work with. Already we can see a problem here! We need 1.5 MW of power to go flank speed, but we only have 0.240 MW of electricity available, so AIP does nothing for our sprint endurance.

Ultimately, the amount of time you can sprint will depend on how much juice your batteries can store. In order to charge your batteries, your power consumption has to be less than 0.240 MW, so you have to be going slow. In fact, if you just do the math, 240/1500 = 0.1666, so if power and speed scaled linearly, you wouldn't even be able to do all ahead 1/3rd using AIP direct! Luckily though, things are much more efficient at lower speeds, so you could probably get a decent amount on AIP only, but definitely not up to sprinting speeds. So AIP will let you do stuff for a long time at slow speeds, but it doesn't help if you need to go really fast.

Which brings us back to square one. What's the sprint endurance of a type 212? Without knowing what kind of batteries it has, who knows? :haha:

[Paulebaer1979]

Which brings us back to square one. What's the sprint endurance of a type 212? Without knowing what kind of batteries it has, who knows? :haha:

You´re absolut right with your posting. I know the battery type, the voltage and the capacitiy of the cells. But i´m not allowed to post it out here.:salute:

206a had 3 batteries with 92 cells each. Every cell had a capacity of round about 8500 A/h - depending on age and maintance. They were just like the batteries in your cars - just a little bit bigger. But the problem with those batteries is that they loose power at high discharge power. At low speed the cells can spend more power than at high speed.