IX D2 or XVIII Walther?
 

Which German submarine is better?

The IX D2 or the XVIII Walther?

What are the differences between them?
I noticed the Walther has a water turbine feature that allows me to clip along at 28 knots...but the H2O2 runs out quickly. The torpedo slots are different as well, and there's no aft torpedo slots in the Walther...which is disappointing.

Are there are other subs you can change to after you get the Walther? Or no?

Unmodded, there is only the Type IXD2 and the Type XVIII. There are a couple of threads that already address the Type XVIII, but since I just finished the German missions in 4 with the Type XVIII, I will give my assessment.

With the exception of diesel range, which the Type IXD2 excels hands-down over the Type XVIII, the Type XVIII is a superior boat, all around. Its standard diesel-electric performance is on par with a Type VIIC boat. It is capable of going much deeper than any other boat in the game. I tested the Type XVIII to 270 meters with no hull damage. The only reason she exceeded the depth gauge (260 meters) is that below 180 meters, the Walter Drive needs to be engaged to maintain depth. The Type XVIII starts with some of the best equipment in the game and what is not included can easily be added after a patrol. No need to worry about the shoddy METOX or the short time BOLD1 canisters. The Walter drive excels in rapid submerged approach from ~10-20km out and is just as good at rapid escapes in tandem with the BOLD launcher. Despite the fact that the Walter Turbines are extremely noisy in the hydrophone(Ahead Slow is 10knots@200rpm), I have yet to aggro any destroyers. Naturally, I dump a BOLD canister to distract them, but the noise of the Walter Drive did not deter them, regardless of speed. I will admit that my detection test is incomplete because I never let an escort close more than 3500m from my position.

The torpedo loading mechanism is the same as the Type XXI boat. six forward tubes, none aft. All with mechanical loading. Likewise, the torpedo loading is quieter and does not seem to attract aggro. Using the Walter Drive in tandem with batteries, when needed, the Type XVIII can dance through convoys and make the lives of the merchantmen and escorts utterly miserable simply because you have the speed to get away.

Historically, this boat never was completed. The Walter Drive looks spiffy on paper, but would have been way too expensive and problematic in practice. The drive relies on ~204 tons of 80% Hydrogen Peroxide solution. This is rocket fuel. While this boat would have been able to go fast enough to force escorts to ASDIC wash-out speed, any hit had potential to damage the fuel cells. High concentration Hydrogen Peroxide is very unstable, ludicrously corrosive and explodes if you look at it the wrong way. The sub would have been like a ship from Star Trek. Super fast, but one good hit in the engine or fuel tank and you blow yourself up. This was also one of many reasons that Germany preferred to complete development of the Type XXI.

In the game, I would quickly trade the range of the Type IXD2 for all of the other boons the Type XVIII has to offer. Submerged, the Type IXD2 is a pig. The Type XVIII is the opposite, which boosts your survival.

I've never played the stock campaign, preferring the traditional Atlantic campaign offered by OM. Of course you can always run two careers, one in each boat. If you decide on the Type IX you might want to look at the great campaign designed exclusively for that boat.
http://www.subsim.com/radioroom/showthread.php?t=171443

well...

my 2 cents on the baot is its got 23 torpedo capacity.
the walter drive lets u go 20 knots under water
and i went to 920 meters in a straight dive. dont know if the walter drive is noisy as i did it in the middle of no where

kinda bummed for the lack deckgun and rear tubes

Flank speed is around 28 knots.


Meters or feet? 920 meters is 3,019 feet. I doubt this is the case. 920 feet (~300m) I believe.

Did more tests after my initial post. The thing is very noisy. However, you can run fast enough to prevent destroyers from doing much to capitalize on it. Top it off with a well placed BOLD3 and the destroyers run around like the Keystone Kops.

The speed and maneuverability make up for the lack of stern tubes. Considering that the U-Boat missions are Late War, the deck gun is next to worthless anyway as almost everything is escorted and/or the weather is too foul to use the thing.

Personally, given this is a sim, i think the best boat is the one that saw actual use, combat, and has ever fired a torpedo in anger. :03: