pre-heating torps

[PortoFerro]

From uboat.net:
G7e

The standard torpedo of the war. It suffered from early problems with its internal depth-keeping equipment, and its firing pistol, but these were solved after the Norwegian Campaign.

In mid 1942 an improved version was introduced with an icreased battery capacity. The increased battery capacity increased the range 50%. The improved G7e was designated T3a. Range was 7500m at 30 knots (preheated state - 4500m at 28 knots).

* data for preheated state. Full effectiveness was obtained when the T2 was preheated electrically to 30 degrees Cent (86 F) before firing. Not preheated figures are 28 knots for 3000m.

And I was preheating my G7a eels...

But for the G7e it seems to be mandatory, right?