Type IXD2's 23700 NM does not compute!

Ducimus · 07-06-10, 06:44 PM

Something about the IXD2's often cited 23,700 NM @ 12 kts has always striked me as incredible.

I noticed wiki's article says: 12,750 nmi (23,610 km) at 10 knots.

Everywhere else says: 23,700 NM @ 12 kts.

But this is wiki were talking about, and not really considered a reliable source. But, it got me looking more closely. Now according to uboat.net:

an IXC is:
76.7 meters long, 6.7 meters wide, goes 13450 @ 10 kts, for 1540 total displacement.

an IXC/40 is:
76.7 meters long, 6.8 meters wide, goes 13850 @ 10 kts, for 1545 total displacement.

An IXD2 is:
87.6 meters long, 7.5 meters wide, goes 23700 @ 12 kts, for 2150 total displacement.

So.....
-an IXC/40 is only 0.8 meters wider, and 5 tons heavier then an IXC.

-an IXD2 is 10.9 meters longer, 0.7 meters wider, and 605 tons heavier.

So with an extra 605 tons, the extra range almost seems plausible....almost. But the thing is, i doubt all that 605 tons was occupied by fuel. IXD2's had two smaller backup engines normal type 9's didn't carry for example. So it still seems like quite a big jump in range.

--------------

Now compare the IXD2, with an equivlant long range attack submarine that could be thought of as a valid comparison.

So here's the IXD2 again:

- 87.6 meters long, 7.5 meters wide, goes 23700 @ 12 kts, for 2150 total displacement.

Followed by a Gato class:

- 95 meters long, 8.3 meters wide, goes 11000 @ 10 kts, for 2424 total displacement.

Mind you both of these boats carry 24 torpedos.

So a gato is, 7.4 meters longer, 0.8 meters wider, and is 274 tons heavier.

Now with wartime modfications of fuel ballast, a gato could go around, im guessing, 13,000 NM give or take. Even then with that additional range, internet sources (which tend to copy each other) mean to tell me that the TypeIXD2 that is 7.4 meters shorter, 0.8 meters skinner, and 274 tons lighter could go an additional 10,700 NM?

I find that a hard pill to swallow, also could it be more then a coicidence that 23700 kilometers converts to 12797 nautical miles? I strongly suspect that somewhere, some source mistakenly cited the KM range as a NM range, and the same mistake has been quoted all over the internet.

Anybody have some hard resources not on the internet to support or refute my hypothesis here?

07-06-10, 06:44 PM	#1
Ducimus Rear Admiral Join Date: May 2005 Posts: 12,987 Downloads: 67 Uploads: 2	Type IXD2's 23700 NM does not compute! Something about the IXD2's often cited 23,700 NM @ 12 kts has always striked me as incredible. I noticed wiki's article says: 12,750 nmi (23,610 km) at 10 knots. Everywhere else says: 23,700 NM @ 12 kts. But this is wiki were talking about, and not really considered a reliable source. But, it got me looking more closely. Now according to uboat.net: an IXC is: 76.7 meters long, 6.7 meters wide, goes 13450 @ 10 kts, for 1540 total displacement. an IXC/40 is: 76.7 meters long, 6.8 meters wide, goes 13850 @ 10 kts, for 1545 total displacement. An IXD2 is: 87.6 meters long, 7.5 meters wide, goes 23700 @ 12 kts, for 2150 total displacement. So..... -an IXC/40 is only 0.8 meters wider, and 5 tons heavier then an IXC. -an IXD2 is 10.9 meters longer, 0.7 meters wider, and 605 tons heavier. So with an extra 605 tons, the extra range almost seems plausible....almost. But the thing is, i doubt all that 605 tons was occupied by fuel. IXD2's had two smaller backup engines normal type 9's didn't carry for example. So it still seems like quite a big jump in range. -------------- Now compare the IXD2, with an equivlant long range attack submarine that could be thought of as a valid comparison. So here's the IXD2 again: - 87.6 meters long, 7.5 meters wide, goes 23700 @ 12 kts, for 2150 total displacement. Followed by a Gato class: - 95 meters long, 8.3 meters wide, goes 11000 @ 10 kts, for 2424 total displacement. Mind you both of these boats carry 24 torpedos. So a gato is, 7.4 meters longer, 0.8 meters wider, and is 274 tons heavier. Now with wartime modfications of fuel ballast, a gato could go around, im guessing, 13,000 NM give or take. Even then with that additional range, internet sources (which tend to copy each other) mean to tell me that the TypeIXD2 that is 7.4 meters shorter, 0.8 meters skinner, and 274 tons lighter could go an additional 10,700 NM? I find that a hard pill to swallow, also could it be more then a coicidence that 23700 kilometers converts to 12797 nautical miles? I strongly suspect that somewhere, some source mistakenly cited the KM range as a NM range, and the same mistake has been quoted all over the internet. Anybody have some hard resources not on the internet to support or refute my hypothesis here?