Water Depth

[Crash1952]

OK, so I'm near center of AN81. Compass says 133 miles north east of nearest English land. Game says 31 meters of water? I'm at 18 meters (depth to keel, correct?) and 13 meters under the keel. That's got to be wrong.

[bstanko6]

If you were walking on the water like Jesus you would have 31 meters of water under you. You boat in the water is 13 meters, the depth under your keel is 18 which equals 31.

[Kaptlt.Endrass]

Correct. The sonar ping is sent to the bottom, wherever that may be, reflects off the ocean floor, and bounces back. The first thing it will hit on it's way up is the keel. The time it takes for it to return is how your nav officer calculates the depth.

It's actually more useful than being told how deep the ocean is; say you want to dive to avoid a hunter-killer patrol in shallow waters. If you're already at periscope depth (anywhere from 12 to 18 metres), and you ask your NO what depth under keel is, then you know exactly how much room you have to manouver before planting the bow into the ocean floor. If you're only given "Sir, the ocean floor is 30 metres deep here sir!", then you'll have to do some quick math, wasting time in a situation where every second counts.

[Crash1952]

Thanks for the replies, but you misunderstood my question. I'm having a hard time believeing that the north sea is only 31 meters deep at that location.

[Von Due]

It doesn't sound unreasonable. The North Sea is not very deep at all, ranging from 20-ish meters in the south to 90-100-ish meters further north. Think of it this way, not that many thousands of years ago, you could walk from today's Belgium to England without getting your feet wet.

[bstanko6]

And so the discussion of Pangea begins...

[Crash1952]

OK, I also did some research on it and I'm surprised at that. Just always thought of 'oceans' (as in many miles from shore, not literal definitions) as being deeper than that. Never too old to learn!!