J.T. Ken. et al:

Think I found the answer to my previous, post dated 03/27/03 02:34, concerning the possibility that U-boat tubes did or did not have rollers in
the bottom of their tubes. I just couldn't buy the notion that they were
"smooth-bore" tubes, 'cause loading them would have be extremely
difficult, no matter how much grease was applied to the torpedo's skin.
I firmly believe that this grease (very stiff at times, due to the North Atlantic temperatures), would be a hindrance in a "smooth-bore" tube.
There just has to be ample clearance between the torpedo and the
torpedo tube.

Then I went through a series of posts regarding the actual tube bore diameters, and the actual diameters of the torpedoes. I was never really satisfied with the data that was offered in several posts by some forum members. I am still confused abut the lengths of the torpedoes, and tubes, bearing in mind the length of the different pistols used and the length of the "floating-piston" used to eject the torpedo. In the case of the "flat-nose" T5 there is no pistol installed ujp frot like the other non-
acoustic units. Perhaps someone, someday will come up with factual
data on this subject.

A few photos of the open breech end of torpedo tubes taken at Birkrhead show a set of lands positioned at 90, 180, and 270 degrees, but I could not determine if rollers were located on the bottom.

I have just come across a photo of the interior of tube #1 on the U-2540.

Click:

[www.diodon349.com]
U2540_torpedo_tubes.jpg

You'll notice the double set of lands on the bottom and the single lands
at 90 and 270 degrees. They appear to measure about 1" thick and 2" wide on the sides and two of them, are about 3" wide, on the bottom.
Therefore, when we speak of internal diameters of the tubes, we have to use the machined surfaces of these lands, This configuration was apparently used to conserve precious steel in fabrication and provide a
means of reducing friction during the torpedo-loading and extraction (for
normal maintenance routines on the torpedoes) processes. But why
apply grease on the afterbody and tail sections of the torpedo, unless the grease was also used as a rust preventive.

I'm forced to come to the conclusion that U-boats did not have tube rollers. Does anyone disagree?

Have a nice day,

ROBERT M.