Csail
N/A
After reading this http://www.ybw.com/auto/newsdesk/20090103103938ymnews.html
i just wondered,how do subs avoid fishing nets?
i just wondered,how do subs avoid fishing nets?
Submarines
- Thread starter Csail
- Start date
boatmike
Well-Known Member
Sometimes they don't methinks.
The places where sub's generally exercise is marked clearly on the chart however and fishing boats are supposed to avoid these areas. Often they don't though and risk "netting" a sub. Fishing boats have sometimes dissapeared without trace and it is often rumoured that they have been dragged under by a sub. It's difficult to substantiate (sic) though and not often proven. The subs have passive (listening) sonar constantly active though and I am told the low speed throb of the big props on fishing boats is very distinctive when they are working and the rumble of a bottom dragging net board is like thunder so I believe the subs can detect fishing boats most of the time OK especially when trawling over the bottom.
The places where sub's generally exercise is marked clearly on the chart however and fishing boats are supposed to avoid these areas. Often they don't though and risk "netting" a sub. Fishing boats have sometimes dissapeared without trace and it is often rumoured that they have been dragged under by a sub. It's difficult to substantiate (sic) though and not often proven. The subs have passive (listening) sonar constantly active though and I am told the low speed throb of the big props on fishing boats is very distinctive when they are working and the rumble of a bottom dragging net board is like thunder so I believe the subs can detect fishing boats most of the time OK especially when trawling over the bottom.
maxi77
Well-Known Member
As mike mentions sometimes they don't, but in general the use of sonar helps boats avoid both fishing boats and other targets. After all if ones is supposed to stay hidden allowing oneself to be caught by random passing fishing boats would be foolish.
Also all RN ships must maintain a fishing boat log in which any 'close encounter' with a fishing boat must be recorded. A good fishing boat log was an empty one, but any captain accused by a fishing boat of damage to nets or gear who did not have a suitable entry in his fishing boat log would have some serious questions to answer.
Also all RN ships must maintain a fishing boat log in which any 'close encounter' with a fishing boat must be recorded. A good fishing boat log was an empty one, but any captain accused by a fishing boat of damage to nets or gear who did not have a suitable entry in his fishing boat log would have some serious questions to answer.
Gordonmc
Well-Known Member
The simple answer is... not easily.
The Carradale (Clyde) trawler Antares was sunk when her trawls caught a sub off the Isle of Arran with the loss of her crew. That led to the introduction of the SubFax scheme to inform mariners of active submarine exercise areas.
The Carradale (Clyde) trawler Antares was sunk when her trawls caught a sub off the Isle of Arran with the loss of her crew. That led to the introduction of the SubFax scheme to inform mariners of active submarine exercise areas.
NormanS
Well-Known Member
If you listen to the Sucfacts broadcasts, when they reel off practically every area, covering the whole of the west coast of Scotland, It makes you proud that we obviously have such a huge fleet of submarines, constantly patroling our waters.
maxi77
Well-Known Member
[ QUOTE ]
The simple answer is... not easily.
The Carradale (Clyde) trawler Antares was sunk when her trawls caught a sub off the Isle of Arran with the loss of her crew. That led to the introduction of the SubFax scheme to inform mariners of active submarine exercise areas.
[/ QUOTE ]
The rarety of such occurances would in fact suggest that submariners are quite good at avoiding fishing boats, particularly when compared with fishing boat sinking for other reasons.
The simple answer is... not easily.
The Carradale (Clyde) trawler Antares was sunk when her trawls caught a sub off the Isle of Arran with the loss of her crew. That led to the introduction of the SubFax scheme to inform mariners of active submarine exercise areas.
[/ QUOTE ]
The rarety of such occurances would in fact suggest that submariners are quite good at avoiding fishing boats, particularly when compared with fishing boat sinking for other reasons.
ValleyForge
Well-Known Member
Didn't poor 'Drum' get clobbered with a periscope out in the Minch ? (about 20 odd yrs ago ...) Vaguely recall her motoring up the clyde a bit low in the bow, or what was left of it.
boatmike
Well-Known Member
You mean that boat that was owned by the pop singer from D'rown D'rown?
boatmike
Well-Known Member
The rarety of such occurances would in fact suggest that submariners are quite good at avoiding fishing boats, particularly when compared with fishing boat sinking for other reasons.
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You mean the rarity of such occurances that are PROVEN to be due to submarines don't you?
It's also worth mentioning for encouragement of the paranoid that the most difficult thing for a submerged sub to detect is a GRP sailing boat...... /forums/images/graemlins/blush.gif
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You mean the rarity of such occurances that are PROVEN to be due to submarines don't you?
It's also worth mentioning for encouragement of the paranoid that the most difficult thing for a submerged sub to detect is a GRP sailing boat...... /forums/images/graemlins/blush.gif
LadyInBed
Well-Known Member
Wasn't there a couple of trawlers that were dragged backwards / sunk in the Irish sea some years back?
It was suspected that subs, maybe Russian in one instance, were the cause.
It was suspected that subs, maybe Russian in one instance, were the cause.
KenMcCulloch
Well-Known Member
[ QUOTE ]
It's also worth mentioning for encouragement of the paranoid that the most difficult thing for a submerged sub to detect is a GRP sailing boat...... /forums/images/graemlins/blush.gif
[/ QUOTE ] Whereas a wooden or steel sailing boat....? I have always assumed that if my echosounder makes enough noise to bounce a signal back of the seabed, any passing submarine should be able to detect it.
It's also worth mentioning for encouragement of the paranoid that the most difficult thing for a submerged sub to detect is a GRP sailing boat...... /forums/images/graemlins/blush.gif
[/ QUOTE ] Whereas a wooden or steel sailing boat....? I have always assumed that if my echosounder makes enough noise to bounce a signal back of the seabed, any passing submarine should be able to detect it.
maxi77
Well-Known Member
[ QUOTE ]
The rarety of such occurances would in fact suggest that submariners are quite good at avoiding fishing boats, particularly when compared with fishing boat sinking for other reasons.
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You mean the rarity of such occurances that are PROVEN to be due to submarines don't you?
It's also worth mentioning for encouragement of the paranoid that the most difficult thing for a submerged sub to detect is a GRP sailing boat...... /forums/images/graemlins/blush.gif
[/ QUOTE ]
I think the proof of my point is that every one is struggling to even find suspicious incidents never mind proven ones. On the other hand serious incidents with fishing boats not involving submarines are common place.
Certainly any sailing vessel can be hard for a boat to find unless of course the echo sounder is running. On the other hand when a boat is dived the top of the fin is at least some 15 feet below the surface, then one only has to miss the 300mm wide look stick. At the end of the day the submariner is trying very hard not to hit you or any one else for that matter.
One of my biggest worries was not yachts or fishing boats but VLCCs heading for Finnart who would stop engines 20 miles south of the Cumbraes and then coast 250000 tonnes of silent death, not a noice thought
The rarety of such occurances would in fact suggest that submariners are quite good at avoiding fishing boats, particularly when compared with fishing boat sinking for other reasons.
___________________________________________________________________
You mean the rarity of such occurances that are PROVEN to be due to submarines don't you?
It's also worth mentioning for encouragement of the paranoid that the most difficult thing for a submerged sub to detect is a GRP sailing boat...... /forums/images/graemlins/blush.gif
[/ QUOTE ]
I think the proof of my point is that every one is struggling to even find suspicious incidents never mind proven ones. On the other hand serious incidents with fishing boats not involving submarines are common place.
Certainly any sailing vessel can be hard for a boat to find unless of course the echo sounder is running. On the other hand when a boat is dived the top of the fin is at least some 15 feet below the surface, then one only has to miss the 300mm wide look stick. At the end of the day the submariner is trying very hard not to hit you or any one else for that matter.
One of my biggest worries was not yachts or fishing boats but VLCCs heading for Finnart who would stop engines 20 miles south of the Cumbraes and then coast 250000 tonnes of silent death, not a noice thought
boatmike
Well-Known Member
Whereas a wooden or steel sailing boat....? I have always assumed that if my echosounder makes enough noise to bounce a signal back of the seabed, any passing submarine should be able to detect it.
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Ken, I am not an expert, but having been involved in the business end of maintaining and refurbishing active and passive sonars for the MoD I have had plenty of conversations with people who are and I think any sailing boat is difficult to detect on the surface. A steel one would probably reflect sound waves a little better than a wooden or GRP one but thats if they are really searching for you with active sonar. Active sonar is not used routinely by subs as it tells everyone on the planet exactly where they are. Passive (listening only) sonar is usually running but if you don't make noise you will not be heard. Your tiny little ping from a low powered echo sounder could possibly be heard but it's a bit of a whisper in a storm frankly and focussed in a pretty narrow beam going straight down. They would certainly detect it as a series of clicks if they were directly beneath you but otherwise I wouldn't rely on it! If you suspect a sub around start your engine and open the throttle wide. He might hear you then!
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Ken, I am not an expert, but having been involved in the business end of maintaining and refurbishing active and passive sonars for the MoD I have had plenty of conversations with people who are and I think any sailing boat is difficult to detect on the surface. A steel one would probably reflect sound waves a little better than a wooden or GRP one but thats if they are really searching for you with active sonar. Active sonar is not used routinely by subs as it tells everyone on the planet exactly where they are. Passive (listening only) sonar is usually running but if you don't make noise you will not be heard. Your tiny little ping from a low powered echo sounder could possibly be heard but it's a bit of a whisper in a storm frankly and focussed in a pretty narrow beam going straight down. They would certainly detect it as a series of clicks if they were directly beneath you but otherwise I wouldn't rely on it! If you suspect a sub around start your engine and open the throttle wide. He might hear you then!
boatmike
Well-Known Member
I think the proof of my point is that every one is struggling to even find suspicious incidents never mind proven ones. On the other hand serious incidents with fishing boats not involving submarines are common place.
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Sorry you haven't got my point. There are as you say plenty of examples at sea documented where fishing boats are sadly lost without trace. Unfortunately many of these losses are totally unexplained. How do you know that a large number of these losses are not caused by subs? You don't! We just don't know. What we do know is that if a foreign sub is lurking around and does cause a fishing boat to be lost, he isn't likely to surface and say sorry is he? /forums/images/graemlins/frown.gif
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Sorry you haven't got my point. There are as you say plenty of examples at sea documented where fishing boats are sadly lost without trace. Unfortunately many of these losses are totally unexplained. How do you know that a large number of these losses are not caused by subs? You don't! We just don't know. What we do know is that if a foreign sub is lurking around and does cause a fishing boat to be lost, he isn't likely to surface and say sorry is he? /forums/images/graemlins/frown.gif
Sandyman
Well-Known Member
''A steel one would probably reflect sound waves a little better than a wooden or GRP one but thats if they are really searching for you with active sonar.''
I may be wrong but i never recall seeing an active sonar that searched for targets on the surface.
If you suspect one of those nasty black things lurking about beneath you then take your portable gas fog horn, stick it in the oggin & give it a long blast. Believe you me it will do the trick /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif
I may be wrong but i never recall seeing an active sonar that searched for targets on the surface.
If you suspect one of those nasty black things lurking about beneath you then take your portable gas fog horn, stick it in the oggin & give it a long blast. Believe you me it will do the trick /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif
maxi77
Well-Known Member
I think you are perhaps deliberately obscuring my point, unexplained losses, tragic though they may be are relatively uncommon. If one adds to that the reality that the only submarines operating round the UK whose position is not known are those of Russia. There are lots of very good reasons why getting caught up in fishing gear is not a good experience for the submarine so it is something which is activelky avoided.
I am well aware that there will always be some who will believe the RN and others will rush around underwater negligently sinking fishing boats and others almost for fun, but I do know that is not the case.
I am well aware that there will always be some who will believe the RN and others will rush around underwater negligently sinking fishing boats and others almost for fun, but I do know that is not the case.
maxi77
Well-Known Member
Quite right submarines rarely use active sonar so hull material will make little difference. if you want to be 'seen' you need to make enough noise, though as I said the real risk of being hit is very sl;ight.
boatmike
Well-Known Member
I may be wrong but i never recall seeing an active sonar that searched for targets on the surface.
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Couldn't possibly comment on how often they do and suspect as I said before that it's not often they use it at all cos it's advertising their own position, but I can confirm they have the capability of acquiring surface targets by active sonar if they want to.
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Couldn't possibly comment on how often they do and suspect as I said before that it's not often they use it at all cos it's advertising their own position, but I can confirm they have the capability of acquiring surface targets by active sonar if they want to.
ValleyForge
Well-Known Member
Flopping about on a sunny calm day off Innellan we saw a line of large bubbles approach us from up the Clyde, which rapidly came alongside & passed on down. Bubbles accompanied by an oily slick & a bit of a greasy whiff. Track speed pretty quick, probably 10kn +. Down in the cabin a strange 'eeeek' was heard (not a 'ping').
Echosounder got switched on PDQ, those in the pub later reckoned it must have been a flash yank using active sonar..... not a whale.
(again many many years ago when Holy Loch was active)
Of course had we been irresponsible oiks a few beer cans would have been chucked over the side to cries of Fire 1, Fire 2 etc. but of course we didn't, not wishing to start WWIII.
Happy days, you don't get such excitment on Windermere sadly.
/forums/images/graemlins/laugh.gif
Echosounder got switched on PDQ, those in the pub later reckoned it must have been a flash yank using active sonar..... not a whale.
(again many many years ago when Holy Loch was active)
Of course had we been irresponsible oiks a few beer cans would have been chucked over the side to cries of Fire 1, Fire 2 etc. but of course we didn't, not wishing to start WWIII.
Happy days, you don't get such excitment on Windermere sadly.
/forums/images/graemlins/laugh.gif
DannyB
Well-Known Member
I recall seeing Drum not long after she was hit, she was lying in Rosneath boatyard getting repaired. The gash in her side must have been at least 20 foot long. Any smaller boat would have gone straight to the bottom. I always wondered if she bent the subs periscope.
