Andy asked:
I wonder… can a modern military submarine (like US or Russian nuclear attack subs) detect a sailing yacht on the surface via sonar or any means other than sticking the scope up and looking around? A sailing yacht is relatively small (no more usually than 40 feet), built of lightweight materials (mostly composite plastic, rarely aluminum or wood or steel) and usually is under sails, using its engine mostly to enter and exit ports. So the only sound it makes is the sound of the hull moving through water. Can modern passive sonars pick it up and distinguish from other sounds of the sea?
OK, one more thing I probably didn’t make clear - I was considering mostly passive sonar, with active sonar that is certainly possible but subs routinely avoid using active sonar as it reveals their presence to other military ships.
Aiden
I wonder… can a modern military submarine (like US or Russian nuclear attack subs) detect a sailing yacht on the surface via sonar or any means other than sticking the scope up and looking around? A sailing yacht is relatively small (no more usually than 40 feet), built of lightweight materials (mostly composite plastic, rarely aluminum or wood or steel) and usually is under sails, using its engine mostly to enter and exit ports. So the only sound it makes is the sound of the hull moving through water. Can modern passive sonars pick it up and distinguish from other sounds of the sea?
OK, one more thing I probably didn’t make clear - I was considering mostly passive sonar, with active sonar that is certainly possible but subs routinely avoid using active sonar as it reveals their presence to other military ships.
Aiden
The first torpedo to reach you.
Comment by spkultr — September 4, 2009 @ 12:57 am
For the boat would have noise though sonar techs are mainly trying to find machinery noises and screw cavitation when searching for.
Comment by Mike W — September 6, 2009 @ 1:49 pm
Sonar requires the return echo of sound. Whales and schools of fish can be picked up. Those are both submerged so the entire object is available for echo return.
In the case of a surface vessel only the submerge portion of the hull is available. Plastic and fiberglass both are pretty good sound insulators. Anything is possible. I seem to recall that subs are required to check the surface, at least in some specific locations close to land, seems that was mentioned when the Japanese ship was hit around HI a few years ago.
Check out the link. Electronic devices can be very complex in theory, operation and repair. The ATM you take cash out of has 2 -3 manuals each about 8 inches thick. There are no more than 5 devices inside it to complete the operation, in the case of sonar/radar/data comm/CCTV/Access Control (card key) and many other systems the operations are both complex and not always easy to predict. Sonar is the one with the most variables to drive operators and repairmen crazy. It is subject to depth/temperature/salinity of the water the math is very complicated and not always accurate.
Edit: Active sonar would likely have trouble. The sound emitted by a small engine could be picked up, not sure at what distance though. A yacht under sail is going to be very very very silent….let me add one more very!
Comment by Wayne C — September 6, 2009 @ 4:07 pm