Naval Historywith Dr. Alex

Q&A · 1:25:53-1:27:13

Why a combined snorkel was not a simple modification

Combining intake and exhaust in a Type VII snorkel avoided underwater back pressure but introduced its own development, detection, and retrofit compromises.

Anti-Submarine WarfareDiesel EnginesSnorkelsSubmarine DesignType VII U-BoatU-Boats
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Question

Why combine exhaust with the snorkel instead of discharging it underwater despite the back pressure?

Short answer

A combined installation could be the more practical retrofit for an older Type VII, even though snorkel exhaust created development and detection tradeoffs.

Notes

Exhaust arrangements evolved and did not always work equally well, while aircraft also used chemical detection methods against submarines. Discharging exhaust underwater created significant back pressure, but lifting it to the surface required additional routing through the snorkel. Any theoretically cleaner system had to fit the age and internal arrangement of the Type VII design. For that older boat, carrying both intake and exhaust through the raised installation could be the more practical retrofit even with its detection and development compromises.