Holy Crap...

[Puster Bill]

Originally Posted by Penelope_Grey

Shnorkels are able to be detected by radar, while snorkelling its a good idea to raise you observation periscope too. But.... in reality, I don't think snorkelling is a good idea because you are a sitting duck, the plane it not spotted till the last moment and you don't have time to get deeper and you cant fight back as you are underwater.

Traditionally, boats equipped with schnorkels would run on battery submerged for most of a 24 hour period, and then schnorkel for the remaining 3 to 4 hours while recharging the batteries. They would have had to keep a periscope watch in effect during that time, as the diesels would deafen the hydrophones.

This wasn't such a disadvantage for the Type XXI and XXIII boats, with their reasonable submerged speeds, but it severely limited the VII and IX boats. That is because instead of being able to travel at an average of 6 to 10 knots to their operation areas, they were limited to 2 or 3 knots, and up to 6 when snorting. That limits the amount of time they can spend 'on station', due to the limited amount of consumables (mainly food and water: Fuel wasn't really a problem, obviously) they could carry.

Schnorkels were detectable by radar, however tests revealed that detection range was cut in half over a surfaced u-boat. The Kriegsmarine tried to reduce that range even further with anti-radar coatings, and to give adequate warning by placing RADAR detector antennas on the schnorkel.

But I digress. Schnorkelling for only a fraction of the day and remaining on batteries the rest is probably the best strategy from a survival standpoint. I just wish you could assign a Watch Officer to periscope watch!