Hi

TopherVIIC Wrote:

> So far I have been told they are strengthening
> vanes. I know if I designed a boat that would be
> subject to explosions and possible grounding, I
> would want to protect the explosive warheads. That

I think, that this framing was not against groudning and explosions.
I believe it was related to the "piston-type" torpedo launching.

These frames are strengthening the tube in the area, where the
guiding recesses for the piston are ending. When the piston is arrested,
there had to occur some stresses, so the strengthening frames may be needed.

See the paragraph 9 and 10 in section General Construction in Chapter III
on page 16 of the british report on U-570 (HMS Graph).
[uboatarchive.net]

"9. The tubes are recessed to take a top lug and the two guides of the
discharge piston, the recesses for the latter ending about 3 ft. short
of the outboard end of the tube.
10. A series of webs is fitted to the outboard end of the tubes abreast the
end of the discharge piston guide recesses, and it is presumed that
these webs are intended to absorb the shock of arresting this piston."

According to the information, these recesses are ending about 1 meter from the
outer end of the tube, and I think it matches with the drawing
you attached from the "Anatomy of the ship".


--
Regards
Maciek


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