Slitherine

Unless German destroyers are not supposed to detect submerged enemy submarines if they are sitting still, I have encountered a strange Sonar Sweep bug in the first scenario of the Kriegsmarine campaign.

I've observed several situations where a submerged Polish submarine remained undetected by Sonar Sweep even though it was clearly in range of the destroyer conducting the sweep. The only way to reveal the submarine was to directly target its hex field by a move order. Afterwards other destroyers in range were able to target and damage the already revealed submarine using their Sonar Sweep.

The posted image shows such a situation where I intentionally encircled an enemy submarine to reproduce the bug: the destroyer on the left fails to detect the submarine by conducting a Sonar Sweep from an adjacent hex, but ordering the bottom destroyer into the center hex reveals it during the same turn.

The only clue I found was that the issue only seemed to arise if the submarine had not changed its position from the previous turn. When trying to reproduce this situation in the "Rising Sun" campaign I could detect submerged submarines just fine, no matter whether they had moved or not.

I've found an official statement in an old thread mentioning that submerged submarines remain undetected by Sonar Sweep if they do not move or attack; so this is an intentional feature.

However, some testing revealed that the game mechanics of this rule depend a lot on whether the alliance in charge of the submarine moves before or after the enemy during a game turn:

- If the submarine's alliance moves after the enemy in each turn, it is sufficient not to have moved or attacked during the previous turn to remain undetected by Sonar Sweep during the current turn.

- If the submarine's alliance moves before the enemy, it is necessary not to have moved or attacked both during this *and* the previous turn, *and* it is further necessary that the submarine hasn't been attacked in between.

This means that it's currently nearly impossible to benefit from this rule if a side is moving first in each turn. Could the rules be adapted so that it's sufficient to sit still in the current turn for the side that moves first?

Thales99 wrote: ↑Tue Sep 17, 2019 8:14 pm However, some testing revealed that the game mechanics of this rule depend a lot on whether the alliance in charge of the submarine moves before or after the enemy during a game turn:
[...]
This means that it's currently nearly impossible to benefit from this rule if a side is moving first in each turn. Could the rules be adapted so that it's sufficient to sit still in the current turn for the side that moves first?

Yep, you're right again. And as the human player usually moves first, one can not use this against the AI effectively. This should be definitely corrected as you described.