Seajet
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:encouragement:
Sub draged fishing boat
- Thread starter BlackPig
- Start date
iain789
Well-Known Member
In 1985 I was on the bridge of HMS Broadsword as we rounded the north end of Skye at dawn. Glorious sunshine!
A couple of hours later a submarine surfaced beside us!
OK - we were there for some torpedo trials at the BUTEC range and PWO(U) in the OPS Room obviously knew it was there, but it was bit surreal. "Need to know"...
In 1982, I was on the bridge of HMS Abdiel heading northwards in Troon Bay, when an American SSN surfaced off our port bow, heading towards us on a steady bearing. We definitely did NOT know she was there until she surfaced, and we did a rapid 180 deg turn to starboard to avoid any unpleasantness. Our CO reckoned we could maneuver better than he could!
On the other hand, last year I was on my own boat, proceeding under sail from Troon to Lamlash, when one of our Trident boats on the surface approached from the north on a steady bearing. I was just weighing up my options when he made a bold turn to port to pass well clear astern of us. I wasn't expecting that!
saltylegs
Well-Known Member
Don't forget "Drum" hitting a sub on the feeder race to the Scottish series around late 80's, between Troon and the bottom of Arran IIRC.
OGITD
Well-Known Member
If in doubt or have any concerns just run your engine .... & the'll have no excuse not to know where you are ...but ... they might not be ours ... so they might just not care ..... I would never rely on your low power (what frequencies do these things run at?) echo sounder.
Give it 'Broadband' (diesel engine) & you should be fine:
http://fas.org/man/dod-101/navy/docs/es310/uw_acous/uw_acous.htm
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Seajet
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OGITD,
many thanks; that's the best answer I've had to a question I've been asking for 30+ years !
As for the comment from elsewhere about the yacht Drum ' hitting a sub ' I'm reminded of the Benny Hill sketch, ' He ran onto my knife - 27 times '
In the interests of both parties, can someone tell us the power and frequency etc of a Yot depthsounder please ?
I might have hoped the sub sonar blokes would know this, and my 2-stroke outboard prop thrashing around would be detectable, but maybe not.
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prv
Well-Known Member
Not sure about power, but the frequency is typically 200KHz. Some use 50KHz instead for better penetration of deep water, and the choice of frequencies also allows you to fit two sounders if you want to for some reason (or perhaps a conventional sounder and a fishfinder) without them confusing each other.
Pete
Seajet
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I tried 2 sounders, a Navico and a NASA, side by side mounted in-hull in the bow Vee section; they did indeed confuse each other.
Now I have the NASA Clipper with transducer in the front - display in the cockpit - for trundling around and a Garmin fishfinder with transonder in the stern, just offset to avoid turbulence from the keel.
I use the Garmin - with display in the saloon - mainly for ' anchor watch ' to tell if it's getting too shallow so we might go aground, or too deep so we might drag.
In the meantime I hope I've got my tide sums right but it's nice to have a backup !
The reason I have 2 systems is that they seemed a better bet than a repeater on the same system, when they were going for the same price.
Now I have the NASA Clipper with transducer in the front - display in the cockpit - for trundling around and a Garmin fishfinder with transonder in the stern, just offset to avoid turbulence from the keel.
I use the Garmin - with display in the saloon - mainly for ' anchor watch ' to tell if it's getting too shallow so we might go aground, or too deep so we might drag.
In the meantime I hope I've got my tide sums right but it's nice to have a backup !
The reason I have 2 systems is that they seemed a better bet than a repeater on the same system, when they were going for the same price.
Davy_S
Well-Known Member
Power? a good fishfinder could be 1000watts peak to peak.
A1Sailor
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Surely an Anderson22 can just engage warp factor 7 and get the hell out of there?OGITD,
many thanks; that's the best answer I've had to a question I've been asking for 30+ years !
As for the comment from elsewhere about the yacht Drum ' hitting a sub ' I'm reminded of the Benny Hill sketch, ' He ran onto my knife - 27 times '
In the interests of both parties, can someone tell us the power and frequency etc of a Yot depthsounder please ?
I might have hoped the sub sonar blokes would know this, and my 2-stroke outboard prop thrashing around would be detectable, but maybe not.
Davy_S
Well-Known Member
Surely any respectable Anderson 22 owner would deploy sonar chaff first!
bikedaft
Well-Known Member
interesting, thanks
but why can i not hear a yacht engine when it is only two boat lengths away with my head underwater, but i can hear the exhaust if i stick my head above water? or are the frequencies from the prop that the subs "hear" different to human audible range? etc. thanks
A1Sailor
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I am sure OGITD could tell how many blades a prop has at a range of 100 miles, given the right acoustic conditions...
Bertramdriver
Well-Known Member
Never had a problem with subs, but then I'm running two big detroit Diesels. It would probably think I'm a Destroyer.