Hi

Hansel Wrote:
-------------------------------------------------------

> First, about the detonators used in the torpedoes,
> were magnetic detonators used with the G7a
> torpedoes, or only contact detonators?

With G7a torpedoes operationaly were used following pistols: Pi-1, Pi-1a, Pi-1c
(with warhead Ka, Ka1, Ka2), Pi-3, Pi-3a, Pi-3c (with warheads Ko, Ko1, Ko2)
and rarely Pi-2, Pi-2a and Pi-2c (With warheads Kb and Kb1).
Of those, Pi-2, Pi-2a, Pi-2c are impact and magnetic pistols.
Pi-3, Pi-3a and Pi-3c pistols are impact pistols so constructed, that can
be used together with magnetic pistols TZ-3


> Second, I understand that the T-II G7e was very
> similar to the T-III G7e. What were the primary
> differences between these two variants? There
> seems to be some confusion about this. For
> example, I heard first that the T-II ran a
> distance of only 3000m at a speed of 28kts, while
> the T-III ran 5000m at a speed of 30kts.


The primary difference was used warhead: in the T-II it was Ka warhead (with
Pi-1 impact pistol), in T-III it was Kb warhead (with Pi-2 impact and magnetic pistol).
The speed for both types was 30 knots, the running distance - 5000 m.
The speed 28 knots was impractical, because TVRe used on U-Boats was
not provided for such speed setting. T-II and T-III had battery 13T.

The torpedo T-IIIa had battery type 17T with greater capacity and running distance 7500 m.

> Later I heard that the difference in range and speed
> reflects a non pre-heated vs. pre-heated battery,
> and the torpedoes were different only in detonator
> mechanism.

Pre-heating the battery (which in turn affects the electrolite
density and chemical reaction velocity) up to 30 deg C had effect
on the battery capacity and maximal output current and no effect
on the output voltage. The torpedo with pre-heated battery achieved
maximum running distance (5000 and 7500 m) respectively.

> Third, with regards to the T-III torpedoes, I've
> read that the pattern running variant had a longer
> range of 7,500m at the same speed of 30kts. How
> was such an improvement in range possible, and was
> this something applied only to the pattern runners
> or the straight running type as well? If
> anything, I would expect additional mechanisms in
> the torpedo used to allow it to run a pattern
> would reduce the maximum range...

It seems, that you refer to the type T-IIIa torpedo. T-IIIa
were straight-runners as well as FAT-II, LUT-I and LUT-II
torpedoes.

> And finally, is there any knowlidge on how common
> the various pattern running and acoustic homing
> torpedoes were in service? Was there an effort to
> replace the older straight running torpedoes
> completely with the newer types, or were they only
> available as an addition to the standard
> versions?

Generally, introducing pattern running torpedoes was the effect
of the tactical changes - as u-boats were no longer able to
approach convoy (or even get inside) to launch effective
straight-runners salvo, they were equipped with weapon, which
could be used from some distance, where some inaccuracy during
solving gyro angles could be compensated by the maneuvering ability
of the torpedo.
Homing torpedo was to be in turn used as weapon against escorts
(mainly in self defence).


--
Regards
Maciek


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