They used one such sub's plane to bomb the US in 1942. The plane from the Japanes sub I-25 bombed a forest near Brookings, Oregon with incendiaries in an attempt to cause forest fires. It was meant to be a retaliation in sort for the Dolittle raid. It was the only time the continental United States was directly bombed during the war.

http://en.wikipedia.org/wiki/Lookout_Air_Raid

US submarines certainly had it easier. That's not the point of this thread. The idea of a what-if is actually the best answer to the OP (which was the best type of boat).

What-if a u-boat was used in the PTO from Pearl instead of a Fleet boat, vs what-if a fleet boat was used as a u-boat out of France (or wherever). MY guess is that the fleet boat would do fine in the ATO as a u-boat (about as well as a u-boat), and the u-boat would not do nearly as well in the PTO. Had the USN faced the same threat level, we would have adapted faster since we'd find the U-boat loss rate utterly unacceptable, and the US was not willing to burn through men without regard to them in the same way the Germans (or Russians, or Japanese) we willing to.

You'd do the what-if for a couple time periods at least. As I said above, I don't think that the deep-diving and maneuverability of the u-boats significantly improved their survival (almost all were sunk). If a fleet type could keep up with the X sinkings, then sunk herself, she'd win the contest unless the u-boat type could sink as many ships with fewer fish, less duration on patrol, horrible tropical heat, etc.

I tend to think that a U-Fleet boat, with all her radar, etc, would be a very capable boat in the hands of the KM, while the u-boats would be more like an S-boat in the PTO. Meaning that the Fleet type was the better, more versatile craft.

You could sort of test this in SH4 assuming you ran equally accurate campaigns/mods.

Odd.:hmm: Now the big question, who is right? (I only have one number about reload times from a type VII. But it is from a novel and therfore I guess it doesn't count but there they reloaded the four tubes manually within 12 minutes (a record time they said). So I find it odd that an automatic is supposed to take 15 min. for 6 tubes....Maybe someone has more reliable data about that...)
BTW.
How long did it take the fleet boats to reload?

@Tater
I don't think the fleet boats would have done good in the ATO, but I wrote the reasons for that already and I don't want to repeat myself. Mybe we should just leave it at that since I don't think this thread will go anywhere.

I know, but the reasons you cite (depth and maneuverability) clearly didn't work, or over 1000 u-boats would not have been sunk.

The edge would clearly go to the germans in the early war in terms of torpedo reliability. As for warhead, I think the torpex USN fish were about the same as the german types, if not more powerful. Stats on hits vs sinkings seem to bear this out (in another thread, I started by believing that german torps were more powerful, but looking at similar sized targets, the mk14s (and models with the same warhead) actually were more likely to sink various target sizes than even the late-war german torps.

That's based on the u-boat.net narratives for the ATO, and Alden's book on USN sub attacks for the PTO (match to japanese records). Note that the number of hits in Alden is if anything high since he lists claimed hits, and I checked vs certain sinking or damaged results (based on the jap records). I checked 7k ships for both, etc, and a higher % of ships actually hit* with one USN torp sank than 1 german torp, even in 1944+.

*this is important obviously because early in the war they failed to hit/detonate enough that it made them look quite bad, indeed, and they were bad—except when they hit, when the torpex really did a good job :)

Depth and "maneuverability" (whatever that comprises!) definitely fall under the category of style, not increased performance in war. As has already been established, style points are not awarded during warfare.

Tater has the H-Bomb on this one. Quitting the discussion would DEFINITELY be in order unless the inferiority of German torpedoes is something we're interested in proving. I left that unsaid on purpose. However Tater has the goods to show without question that the stats on the ingredients of German torpedos and their performance are seriously at odds. U-Boat worshippers are not subject to falsification, even if their own numbers show how ineffective their torpedoes were vs Mark 14s and Mark 18s, especially toward the last 18 months of the war.

You know, this is about arguing whether Robert E Lee or US Grant was the superior general in the American Civil War. All the style points go to Lee, but Grant showed that ugly wins just fine. Decision: Grant.

German torpedoes were excellent, don't get me wrong (though the USN and KM were both put to shame by the IJN, hands-down).

I think that the warheads were probably pretty comparable, frankly. I think that the 292kg of torpex was at the very least about the same as 300kg hexanite, and quite possibly more powerful.

I think any argument that states the strength of one vs the other as being definitive is flat out wrong (in either direction). I don't think it is at all clear. I have seen folks argue that the G7e should be MORE powerful, and I looked into the sinkings as a reality check and was actually surprised to find that the m14 was more effective (when they actually exploded, lol) as they were. (measured by the % of attacks with only 1 hit on a given size target that ended up sinking. 1-hit sinkings for all 7,000 ton ships (I have the stats for every single attack on said size in a spreadsheet for the whole war) were something like 69% as I recall for the USN fish, and around half that for german attacks on Liberty Ships in 1944—and the Liberty was a POS in terms of construction, they were quite fragile.

The mk 18, OTOH, is likely weaker than the G7e it copied. I don't have breakdowns on the fish used for the late-war USN attacks I checked, so I'm certain a % were actually with the weaker mk18 (which lowers the stats vs the german fish, actually).

So it is fair to say the 2 navies had VERY similar fish in terms of warhead strength.

Caveat: some numbers list heavier warheads (some lighter, too) for the G7 fish. If there was a sub-model with a significantly larger warhead than 300kg, clearly the strength balance would shift. Navweaps says some sources have a 430kg number which would clearly be more powerful than 292kg of torpex by a ways.

Nope I also said that you can't make good use of your radar since the British could detect it. That would mean that you will attract a lot of hunter / killer groups while the convoys evade you. Without radar the fleet boat is more vulnerable to planes (as long as the planes don't use radar since the fleet boat can detect it too) because of the slower dive time. And once you are detected by British ASW vessels (I think after sinking some of there merchants they know that you are there;)) the bigger size of your boat makes you also a bigger target that (usually) doesn't dive as deep as a u-boat.

Ok lets solve the issue within the SH4 framework! How about two "what if" campaigns or series of scenarios/battles with:
1. U-boats vs IJN and merchant marine and
2. Fleetboats vs Allied Navy and merchant marine.

What the heck! we're supposed to be subsimmers...

Clearly deep-diving didn't work, though (unless you count diving all the way to the bottom, forever, as the large majority of u-boats did ;) )

Dive times... yeah, u-boats were faster on average, but in the fleet type books I've read (written by the skippers or crew) they were aiming for 30-something second crash dive times.

I actually agree the fleet type would not have been as effective against the allies by a considerable margin, though I'm a little at doubt as to how much worse it could have been than the u-boats. What % of u-boats were sunk? 90%? There's really not much room to do worse than that, and even if the fleet type WAS worse (probably true in the ATO, I'll grant you), it only had a few % points worse available to it. So if the u-boat was not at least that much better than the fleet boat in the PTO, the fleet "wins."

Get what I'm saying?

I recently read war patrol reports of the USS Drum. In one of them the skipper wrote that they achived 45 sec (IIRC) and that that was an improvement over the crash dive tests done prevoiusly by the same boat and crew.

*Edit*
Found it:
http://www.drum228.org/warpatrol09.html#personnel

*/Edit*


Well there are still 10% to go.;)

Well it can be worse by sinking less ships than the u-boats did. The large fleet boats are easyier to detect (but to stay fair I have to admit that if the fleet boat gets a shot it can do more damage).

I think we are again at my first post in this thread. Each type of sub was best for it's theatre.:sunny:

A couple of points need to be addressed:

Diesel Electric propulsion: A diesel engine turns a generator to create electricity. The engine itself is not directly connected to the propeller shaft. The electricity created by the generator is then sent to high speed electric motors that are connected to the shaft through reduction gears. These same generator engines also charge the battery.

Advantages:

1. The engine does not have to be aligned with the propeller shaft, allowing a more efficient engine room arrangement.

2. Complex, damage prone, and hard to maintain clutches are eliminated from the drive train.

3. The engines can be run at their most fuel efficient speed, as speed is regulated by sending more or less current to the motors.

4. Constant speed operation greatly reduces wear and tear on the engines.

5. Generally, a much greater amount of electricity can be produced, allowing for greater hotel loads (better habitability) and more powerful electronics (i.e. radar and sonar).

Disadvantages:

1. Generally requires a larger submarine

Towards the end of the war, the U.S. replaced the high speed motors with slow speed models, allowing the elimination of reduction gears, which were very sensitive to depth charge damage.

Diesel Direct propulsion: A diesel engine is connected via a clutch to a combination generator/motor, which is directly connected to the propeller shaft via reduction gears. For surface propulsion the diesel is directly turning the shaft through the clutch. Some arrangements have a 2nd clutch aft of the generator/motor so the engine can charge the battery without providing propulsion. For submerged propulsion, the engine is secured and declutched from the shaft. Electricity from the battery is fed to the generator/motor which turns the shaft.

Advantages:

1. Due to the generator and motor being the same unit, you can have a smaller submarine.

Disadvantages:

1. Generally, the reverse of all the advantages of Diesel Electric.

2. There is no transmission or reverse gear in the drive train, so in order to back down, the engine has to be declutched and current has to be sent the the other side of the motor from the battery. Greatly slows and complicates maneuvering orders, especially in critical situations in harbors.

3. Because the engine is directly connected to the propeller shaft, you can only have two engines in your submarine! You can add some additional generator only engines for charging or electrical loads, but these can't be used for propulsion. On two separate occasions, the U.S. Navy experimented with connecting two diesels in tandem at the crankshaft, but these experiments were dismal failures. It is virtually impossible to precisely match the speeds of the two engines. Any mismatch is speed results in incredible torsional vibrations in the crankshafts and eventually broken crankshafts or engine mounts.

As for air conditioning: The major advantage of A/C on the fleet boats was not in providing crew comfort (which it did), but in greatly reducing humidity. Condensation in a submerged submarine is a huge problem. The condensate drips into electrical circuits and causes fires. The degree of mechanical reliability this gave to the Fleet Boats in incalculable.

This is a interesting discussion, but with no good answer. I think of it in this way: Which is the better airplane, a P-51 Mustang fighter, or a C-47 Dakota cargo plane? The answer is both. The P-51 is faster, more maneuverable, and carries a heavy armament. The C-47 has a much greater range and payload. The same line of thought applies to submarines. The Fleet Boat and the Type VII or IX were designed with completely different operating parameters and requirements. Both excelled in their respective areas, but can not be directly compared.

Dave

www.pigboats.com

No, I think the fleet was a better all around sub.

45 seconds is decent for a dive, but in Silent Running, he talks about getting under 40 seconds.

In addition, RR mentioned something in another thread that has some bearing. He said that US skippers virtually never put the planes at more than a 10 degree dive angle during the war (previous training, etc?), but that after the war, Guppy boats (modified fleets) dived at steeper angles and sped dive times. If there was no physical limitation on that, and if u-boat skippers ever put more than 10 degrees on the planes, then tithe crash dive time might literally evaporate simply by ordering "15 degrees down!" There is also the whole diving party stuff (guys running forward which was not done in US boats at all).

Might be interesting to see what they could have done with dive times just by different doctrine, no changes to the boat.

Tench schemes 2 and 3 are listed with TEST depths of 1000', BTW. So the US could have easily modified Balao/Tench to go as deep as any u-boat, looks like.

RR points out in the other thread that Archerfish did tests and found they could dive at 25 degrees down bubble, no problem vs the 10 degrees used universally during the war.

So the fleet could have crash dived considerably fast with no more change than a differently trained skipper giving the orders. What was a u-boat crash dive angle?

The whole thing is VERY interesting speculation from any viewpoint. One thing fascinating about the U-Boats is how they got a large percentage of the utility out of much less technology. We talk about the aspect ratio method of measuring AoB. Of course with radar and good plotting you can measure that really precisely with a protractor.

Without radar, using their OLC Gui (insert German name for the real device here) they could measure AoB just about as precisely without all the technology, but just as quickly! The ingenuity of doing with less is often more admirable than brute force techological assault. But again, we're talking style points here. You really can get 15% better performance for about 300 times the effort and expense. The fleet boat proved it.

From our standpoint it's impossible to not admire the little guy who did 85% of the job with one third of the resources. But they would have died to get that extra 15%, no matter what it cost.

And that is the difference between the U-Boat sailor's view of the situation, if they had had the facts, and ours, safely speculating from the security of our cozy 21st century homes.

You have to be really careful with large down angles when submerging. Much greater than 10 degrees and you risk sticking the props out of the water. You have to remember that these boats were mostly driven under by the combined effects of the diving planes and propulsion. Stick the props out of the water and you eliminate the effect of propulsion and greatly slow the dive times.

For informational purposes: I qualified in submarines on the USS Darter SS-576 in 1984. The Darter was post war diesel boat very similar to the Fleet Boats.

Dave

www.pigboats.com