Tech.s to clear up fishnets entangled on a Wreck

aquatiker · 29th July 2007, 13:25

Dear all,

I was wondering if anyone has any procedure or methodology that besides safe, allows divers to clear up a wreck filled with fishing nets, of several kinds.

That is, what´s the best way?
- Cut small pieces, and keep them on a mesh bag, doing it over and over?
-trying to roll the nets as a single portion tied up?
-Other?...

Thanks, i would really thank for any replies since as you know this can be a tricky thing to do within a safety margin.

Drmike · 29th July 2007, 14:28

Quote: (Originally Posted by aquatiker)

Dear all,

I was wondering if anyone has any procedure or methodology that besides safe, allows divers to clear up a wreck filled with fishing nets, of several kinds.

That is, what´s the best way?
- Cut small pieces, and keep them on a mesh bag, doing it over and over?
-trying to roll the nets as a single portion tied up?
-Other?...

Thanks, i would really thank for any replies since as you know this can be a tricky thing to do within a safety margin.

Its a huge amount of hard work to try to do it manually. I wouldnt even try on anything but the smallest portion or recent net

To clean up heavily netted wrecks we often tie a strong (tight) line from the netting to the anchor chain and let the ships movement (sea swell) tear off the net overnight/day as were diving. You can also use the anchor whinch (or rising boat) to pull it off. Be aware that pulling netting off can cause significant damage to the wreck/expose new stuff (which is sometimes the motivation)

UKSteve · 29th July 2007, 15:29

Agree with Mike ...it takes a lot of work...

Have done it on quite a small wreck which was recently netted. Tied a lifting bag on one end (where there was a clear end) and blowing it to create lift and then working back along the net, pulling it free bit by bit.

You need to limit the number of divers in the water and be very aware of your position in the water relative to the net being lifted and that still on the wreck.

Biggest concern is the net tearing free and pulling you up towards the surface with it.

Once the first lifting bag reaches the surface a second is attached at the wreck depth to apply more lift. I believe this is a safer way of working than rolling up on the bottom cos there is a lot less possibility of entanglement and less effected by current on a wreck.

Worst job of the lot is loading the stinking pile of rotting net etc onto the boat!! In the middle east it turned rather ripe rather quickly!!

Dive knives are pretty much useless unless the net it under tension.. far better to use scissors / surgical shears.

Steve

maayanh · 29th July 2007, 17:13

I have done several dives to clear up fishnets, the techniques I've used are as following:

if the net was relatively new (less entangled, and only a few layers of net) then the technique was: to roll up the net (cutting and tearing where required) and every time it get to be 2 feet diameter , cut it off, tying it off and secure it on the side. after finishing all the area (or time) collecting the various rolls. and sending them to the surface vie lift bag. For a medium net this usually takes 60-90 minutes for 4 divers working simultaneously (more if the haven't done it before).

if the nets are old or in many layers than rolling up the net is almost impossible, and we usually only cut to expose entrances and exits and to remove specific peaces we find dangerous or interesting.

In every dive I've gone to remove netting (pieces more than 200 meters long) I've gotten at least a little entangled. therefor I use some variation of the rule of thirds when dealing with nets to make sure that even if I get entangled I still have time to get untangled. we go over all the equipment were taking and remove any thing non essential

(including buckles) tie off/tape up any straps. and make sure that every diver has at least two sharp cutting instruments. and while diving that each diver is seen by at least two other diver that can help them when (not if) they become entangled.

please note, I have not tried to use a lot of force to remove netting for fear of detestableising the wreck if that is not an issue that would defenaltly save time

aquatiker · 30th July 2007, 07:01

Quote: (Originally Posted by Drmike)

Its a huge amount of hard work to try to do it manually. I wouldnt even try on anything but the smallest portion or recent net

To clean up heavily netted wrecks we often tie a strong (tight) line from the netting to the anchor chain and let the ships movement (sea swell) tear off the net overnight/day as were diving. You can also use the anchor whinch (or rising boat) to pull it off. Be aware that pulling netting off can cause significant damage to the wreck/expose new stuff (which is sometimes the motivation)

Thanks Mike: Yes it will be a lot of work, done by several teams and several dives.
In this case i believe that using force would defenetly cause damage, plus there are several spots where they´re entangled as you may imagine. It could be done spot by spot, but even so the damage could be significant.

Anyway that way would be the safest! Thanks for your reply.

aquatiker · 30th July 2007, 07:13

Quote: (Originally Posted by UKSteve)

Agree with Mike ...it takes a lot of work...

Have done it on quite a small wreck which was recently netted. Tied a lifting bag on one end (where there was a clear end) and blowing it to create lift and then working back along the net, pulling it free bit by bit.

You need to limit the number of divers in the water and be very aware of your position in the water relative to the net being lifted and that still on the wreck.

Biggest concern is the net tearing free and pulling you up towards the surface with it.

Once the first lifting bag reaches the surface a second is attached at the wreck depth to apply more lift. I believe this is a safer way of working than rolling up on the bottom cos there is a lot less possibility of entanglement and less effected by current on a wreck.

Worst job of the lot is loading the stinking pile of rotting net etc onto the boat!! In the middle east it turned rather ripe rather quickly!!

Dive knives are pretty much useless unless the net it under tension.. far better to use scissors / surgical shears.

Steve

Thanks Steve!

When i started to read a "lift bag on one end", my concern was the possibility of one or more divers getting caught on huge ghost net, being shoot towards the surface.
There are a lot of nets down there, some older than others, and therefore with some tension they can tear appart, while other parts won´t.

I would like to avoid creating a "curtain" of fishing nets ready to go top side.
One rip, and there it goes! Or stronger currents, low viz, and we have a deadly trap specially if someone else decides to go to that wreck (outside our team) not knowing what is being done.

Yup, keeping it simpler than usual, diminuishing all possible edges, scisors and cirurgical or those special blades (rather cheap) to cut carpets.(sorry can´t remember it´s proper name).

If the nets will be either kept on mesh bags, or wrapped, i hope than it won´t cause a lot of mess when surface; after all, in either situations their rapped on portions and secured.

aquatiker · 30th July 2007, 07:33

Quote: (Originally Posted by maayanh)

I have done several dives to clear up fishnets, the techniques I've used are as following:

if the net was relatively new (less entangled, and only a few layers of net) then the technique was: to roll up the net (cutting and tearing where required) and every time it get to be 2 feet diameter , cut it off, tying it off and secure it on the side. after finishing all the area (or time) collecting the various rolls. and sending them to the surface vie lift bag. For a medium net this usually takes 60-90 minutes for 4 divers working simultaneously (more if the haven't done it before).

if the nets are old or in many layers than rolling up the net is almost impossible, and we usually only cut to expose entrances and exits and to remove specific peaces we find dangerous or interesting.

In every dive I've gone to remove netting (pieces more than 200 meters long) I've gotten at least a little entangled. therefor I use some variation of the rule of thirds when dealing with nets to make sure that even if I get entangled I still have time to get untangled. we go over all the equipment were taking and remove any thing non essential

(including buckles) tie off/tape up any straps. and make sure that every diver has at least two sharp cutting instruments. and while diving that each diver is seen by at least two other diver that can help them when (not if) they become entangled.

please note, I have not tried to use a lot of force to remove netting for fear of detestableising the wreck if that is not an issue that would defenaltly save time

Hi maayanh:

We have old and new pieces mixed all together; it will be quite a lot of work, for a few months!..
Anyway we got a pretty got number of divers split in 3 ind/team to work on specific spots.
Probably 4/team would be safer; 2 working, 2 monitoring in turns.

I also considered the idea of getting a regular vest,

but putted on top of the harness, and reversed; that is, all pockets turned inside, as was as buckles, etc. That way all instruments would not turn into edgy points and if one diver requires anything kept inside if, it´s just a matter of unzipping and zipping it again. If in a messy situation or with a lot of nets hanging out, that procedure should be done away from the wreck.

Another thing, would be to cover all units/tanks with a nice wrap with an elastic band on the end. (material: probably the same used in trucks to cover cargo).

These two ways would be a nice, safe and cheap way for us divers to keep it withing some safety margins.

Also thanks for reminding the thirds rule; i consider it as well, plus, i would like every team to have a bailout tank close (few meters) to the spot their working on, in case of necessity.

Still, i´m not yet convinced on what should be best...

Maybe partially as you said; new pieces rolled up and tied by small sections.

Older cutted of and kept on a mesh bag, or plastic bag to avoid getting stuck.

What about this?...

Rule to decide aging process on nets; (on pull, breaking off?..that can be somehow trickier, since their wrapped on each other..)

It´s going to be a hell of an operation!

(hell as in a lot of work, hopefully!!)

UKSteve · 30th July 2007, 11:31

Quote: (Originally Posted by aquatiker)

Thanks Steve!

When i started to read a "lift bag on one end", my concern was the possibility of one or more divers getting caught on huge ghost net, being shoot towards the surface.
There are a lot of nets down there, some older than others, and therefore with some tension they can tear appart, while other parts won´t.

I would like to avoid creating a "curtain" of fishing nets ready to go top side.
One rip, and there it goes! Or stronger currents, low viz, and we have a deadly trap specially if someone else decides to go to that wreck (outside our team) not knowing what is being done.

Yup, keeping it simpler than usual, diminuishing all possible edges, scisors and cirurgical or those special blades (rather cheap) to cut carpets.(sorry can´t remember it´s proper name).

If the nets will be either kept on mesh bags, or wrapped, i hope than it won´t cause a lot of mess when surface; after all, in either situations their rapped on portions and secured.

No probs at all...every job is different too. Mine was a smallish wreck in about 20m of crystal clear water off Oman in the Middle East. We got the recently shared net off in one day's work with a team of 6 divers.

Quite agree that it is not the appropriate method in lousy vis etc.

Why do you need to remove the net by the way?

Steve

aquatiker · 31st July 2007, 09:47

Quote: (Originally Posted by UKSteve)

No probs at all...every job is different too. Mine was a smallish wreck in about 20m of crystal clear water off Oman in the Middle East. We got the recently shared net off in one day's work with a team of 6 divers.

Quite agree that it is not the appropriate method in lousy vis etc.

Why do you need to remove the net by the way?

Steve

Hey there!
Crystal clear waters..that would be nice and easier;Greenish is what we have

(ok, brownish once in a while, and green turning to blue a few days over the whole year)

We want to remove the nets, considering the huge amount that has been covering the wreck turning it into a by-catch trap and within a few years really hazardous to divers.

More ideas, or critics are welcome!

Cheers

UKSteve · 31st July 2007, 10:04

Quote: (Originally Posted by aquatiker)

We want to remove the nets, considering the huge amount that has been covering the wreck turning it into a by-catch trap and within a few years really hazardous to divers.

Can definitely relate to the by-catch aspect.. must be one of the saddest sights to see.. fish, turtles etc trapped in lost nets, fish pots etc.

BTW ..if the wreck is fished regularly...watch out for hooks and monofiliment snagged in the net.. could be hiden under algae growth until you grab it with fingers... ouch!! Real snagging risk too. Again the knife is useless, slashers / shears essential..and placed where you can easily reach them (which is not generally the calf!!)

Steve

29th July 2007, 13:25	#1 (permalink)
aquatiker New Member Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Nov 2006 Location: Portugal Posts: 14	Tech.s to clear up fishnets entangled on a Wreck Dear all, I was wondering if anyone has any procedure or methodology that besides safe, allows divers to clear up a wreck filled with fishing nets, of several kinds. That is, what´s the best way? - Cut small pieces, and keep them on a mesh bag, doing it over and over? -trying to roll the nets as a single portion tied up? -Other?... Thanks, i would really thank for any replies since as you know this can be a tricky thing to do within a safety margin.
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29th July 2007, 14:28	#2 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,128	Re: Tech.s to clear up fishnets entangled on a Wreck Quote: (Originally Posted by aquatiker) Dear all, I was wondering if anyone has any procedure or methodology that besides safe, allows divers to clear up a wreck filled with fishing nets, of several kinds. That is, what´s the best way? - Cut small pieces, and keep them on a mesh bag, doing it over and over? -trying to roll the nets as a single portion tied up? -Other?... Thanks, i would really thank for any replies since as you know this can be a tricky thing to do within a safety margin. Its a huge amount of hard work to try to do it manually. I wouldnt even try on anything but the smallest portion or recent net To clean up heavily netted wrecks we often tie a strong (tight) line from the netting to the anchor chain and let the ships movement (sea swell) tear off the net overnight/day as were diving. You can also use the anchor whinch (or rising boat) to pull it off. Be aware that pulling netting off can cause significant damage to the wreck/expose new stuff (which is sometimes the motivation) __________________ Get a girlfriend you sad twat - a Rebreather is an unfaithful mistress - dont blind yourself to her faults just because she goes down on you
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29th July 2007, 15:29	#3 (permalink)
UKSteve Still a novice... Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Jul 2005 Location: Weymouth, UK Posts: 557	Re: Tech.s to clear up fishnets entangled on a Wreck Agree with Mike ...it takes a lot of work... Have done it on quite a small wreck which was recently netted. Tied a lifting bag on one end (where there was a clear end) and blowing it to create lift and then working back along the net, pulling it free bit by bit. You need to limit the number of divers in the water and be very aware of your position in the water relative to the net being lifted and that still on the wreck. Biggest concern is the net tearing free and pulling you up towards the surface with it. Once the first lifting bag reaches the surface a second is attached at the wreck depth to apply more lift. I believe this is a safer way of working than rolling up on the bottom cos there is a lot less possibility of entanglement and less effected by current on a wreck. Worst job of the lot is loading the stinking pile of rotting net etc onto the boat!! In the middle east it turned rather ripe rather quickly!! Dive knives are pretty much useless unless the net it under tension.. far better to use scissors / surgical shears. Steve Last edited by UKSteve : 29th July 2007 at 15:36.
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29th July 2007, 17:13	#4 (permalink)
maayanh New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Not Bought Yet Join Date: Jan 2007 Posts: 18	Re: Tech.s to clear up fishnets entangled on a Wreck or reef I have done several dives to clear up fishnets, the techniques I've used are as following: if the net was relatively new (less entangled, and only a few layers of net) then the technique was: to roll up the net (cutting and tearing where required) and every time it get to be 2 feet diameter , cut it off, tying it off and secure it on the side. after finishing all the area (or time) collecting the various rolls. and sending them to the surface vie lift bag. For a medium net this usually takes 60-90 minutes for 4 divers working simultaneously (more if the haven't done it before). if the nets are old or in many layers than rolling up the net is almost impossible, and we usually only cut to expose entrances and exits and to remove specific peaces we find dangerous or interesting. In every dive I've gone to remove netting (pieces more than 200 meters long) I've gotten at least a little entangled. therefor I use some variation of the rule of thirds when dealing with nets to make sure that even if I get entangled I still have time to get untangled. we go over all the equipment were taking and remove any thing non essential (including buckles) tie off/tape up any straps. and make sure that every diver has at least two sharp cutting instruments. and while diving that each diver is seen by at least two other diver that can help them when (not if) they become entangled. please note, I have not tried to use a lot of force to remove netting for fear of detestableising the wreck if that is not an issue that would defenaltly save time Last edited by maayanh : 29th July 2007 at 17:15. Reason: spelling
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30th July 2007, 07:01	#5 (permalink)
aquatiker New Member Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Nov 2006 Location: Portugal Posts: 14	Re: Tech.s to clear up fishnets entangled on a Wreck Quote: (Originally Posted by Drmike) Its a huge amount of hard work to try to do it manually. I wouldnt even try on anything but the smallest portion or recent net To clean up heavily netted wrecks we often tie a strong (tight) line from the netting to the anchor chain and let the ships movement (sea swell) tear off the net overnight/day as were diving. You can also use the anchor whinch (or rising boat) to pull it off. Be aware that pulling netting off can cause significant damage to the wreck/expose new stuff (which is sometimes the motivation) Thanks Mike: Yes it will be a lot of work, done by several teams and several dives. In this case i believe that using force would defenetly cause damage, plus there are several spots where they´re entangled as you may imagine. It could be done spot by spot, but even so the damage could be significant. Anyway that way would be the safest! Thanks for your reply.
(Offline)

30th July 2007, 07:13	#6 (permalink)
aquatiker New Member Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Nov 2006 Location: Portugal Posts: 14	Re: Tech.s to clear up fishnets entangled on a Wreck Quote: (Originally Posted by UKSteve) Agree with Mike ...it takes a lot of work... Have done it on quite a small wreck which was recently netted. Tied a lifting bag on one end (where there was a clear end) and blowing it to create lift and then working back along the net, pulling it free bit by bit. You need to limit the number of divers in the water and be very aware of your position in the water relative to the net being lifted and that still on the wreck. Biggest concern is the net tearing free and pulling you up towards the surface with it. Once the first lifting bag reaches the surface a second is attached at the wreck depth to apply more lift. I believe this is a safer way of working than rolling up on the bottom cos there is a lot less possibility of entanglement and less effected by current on a wreck. Worst job of the lot is loading the stinking pile of rotting net etc onto the boat!! In the middle east it turned rather ripe rather quickly!! Dive knives are pretty much useless unless the net it under tension.. far better to use scissors / surgical shears. Steve Thanks Steve! When i started to read a "lift bag on one end", my concern was the possibility of one or more divers getting caught on huge ghost net, being shoot towards the surface. There are a lot of nets down there, some older than others, and therefore with some tension they can tear appart, while other parts won´t. I would like to avoid creating a "curtain" of fishing nets ready to go top side. One rip, and there it goes! Or stronger currents, low viz, and we have a deadly trap specially if someone else decides to go to that wreck (outside our team) not knowing what is being done. Yup, keeping it simpler than usual, diminuishing all possible edges, scisors and cirurgical or those special blades (rather cheap) to cut carpets.(sorry can´t remember it´s proper name). If the nets will be either kept on mesh bags, or wrapped, i hope than it won´t cause a lot of mess when surface; after all, in either situations their rapped on portions and secured.
(Offline)

30th July 2007, 07:33	#7 (permalink)
aquatiker New Member Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Nov 2006 Location: Portugal Posts: 14	Re: Tech.s to clear up fishnets entangled on a Wreck or reef Quote: (Originally Posted by maayanh) I have done several dives to clear up fishnets, the techniques I've used are as following: if the net was relatively new (less entangled, and only a few layers of net) then the technique was: to roll up the net (cutting and tearing where required) and every time it get to be 2 feet diameter , cut it off, tying it off and secure it on the side. after finishing all the area (or time) collecting the various rolls. and sending them to the surface vie lift bag. For a medium net this usually takes 60-90 minutes for 4 divers working simultaneously (more if the haven't done it before). if the nets are old or in many layers than rolling up the net is almost impossible, and we usually only cut to expose entrances and exits and to remove specific peaces we find dangerous or interesting. In every dive I've gone to remove netting (pieces more than 200 meters long) I've gotten at least a little entangled. therefor I use some variation of the rule of thirds when dealing with nets to make sure that even if I get entangled I still have time to get untangled. we go over all the equipment were taking and remove any thing non essential (including buckles) tie off/tape up any straps. and make sure that every diver has at least two sharp cutting instruments. and while diving that each diver is seen by at least two other diver that can help them when (not if) they become entangled. please note, I have not tried to use a lot of force to remove netting for fear of detestableising the wreck if that is not an issue that would defenaltly save time Hi maayanh: We have old and new pieces mixed all together; it will be quite a lot of work, for a few months!.. Anyway we got a pretty got number of divers split in 3 ind/team to work on specific spots. Probably 4/team would be safer; 2 working, 2 monitoring in turns. I also considered the idea of getting a regular vest, but putted on top of the harness, and reversed; that is, all pockets turned inside, as was as buckles, etc. That way all instruments would not turn into edgy points and if one diver requires anything kept inside if, it´s just a matter of unzipping and zipping it again. If in a messy situation or with a lot of nets hanging out, that procedure should be done away from the wreck. Another thing, would be to cover all units/tanks with a nice wrap with an elastic band on the end. (material: probably the same used in trucks to cover cargo). These two ways would be a nice, safe and cheap way for us divers to keep it withing some safety margins. Also thanks for reminding the thirds rule; i consider it as well, plus, i would like every team to have a bailout tank close (few meters) to the spot their working on, in case of necessity. Still, i´m not yet convinced on what should be best... Maybe partially as you said; new pieces rolled up and tied by small sections. Older cutted of and kept on a mesh bag, or plastic bag to avoid getting stuck. What about this?... Rule to decide aging process on nets; (on pull, breaking off?..that can be somehow trickier, since their wrapped on each other..) It´s going to be a hell of an operation! (hell as in a lot of work, hopefully!!)
(Offline)

30th July 2007, 11:31	#8 (permalink)
UKSteve Still a novice... Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Jul 2005 Location: Weymouth, UK Posts: 557	Re: Tech.s to clear up fishnets entangled on a Wreck Quote: (Originally Posted by aquatiker) Thanks Steve! When i started to read a "lift bag on one end", my concern was the possibility of one or more divers getting caught on huge ghost net, being shoot towards the surface. There are a lot of nets down there, some older than others, and therefore with some tension they can tear appart, while other parts won´t. I would like to avoid creating a "curtain" of fishing nets ready to go top side. One rip, and there it goes! Or stronger currents, low viz, and we have a deadly trap specially if someone else decides to go to that wreck (outside our team) not knowing what is being done. Yup, keeping it simpler than usual, diminuishing all possible edges, scisors and cirurgical or those special blades (rather cheap) to cut carpets.(sorry can´t remember it´s proper name). If the nets will be either kept on mesh bags, or wrapped, i hope than it won´t cause a lot of mess when surface; after all, in either situations their rapped on portions and secured. No probs at all...every job is different too. Mine was a smallish wreck in about 20m of crystal clear water off Oman in the Middle East. We got the recently shared net off in one day's work with a team of 6 divers. Quite agree that it is not the appropriate method in lousy vis etc. Why do you need to remove the net by the way? Steve
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31st July 2007, 09:47	#9 (permalink)
aquatiker New Member Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Nov 2006 Location: Portugal Posts: 14	Re: Tech.s to clear up fishnets entangled on a Wreck Quote: (Originally Posted by UKSteve) No probs at all...every job is different too. Mine was a smallish wreck in about 20m of crystal clear water off Oman in the Middle East. We got the recently shared net off in one day's work with a team of 6 divers. Quite agree that it is not the appropriate method in lousy vis etc. Why do you need to remove the net by the way? Steve Hey there! Crystal clear waters..that would be nice and easier;Greenish is what we have (ok, brownish once in a while, and green turning to blue a few days over the whole year) We want to remove the nets, considering the huge amount that has been covering the wreck turning it into a by-catch trap and within a few years really hazardous to divers. More ideas, or critics are welcome! Cheers
(Offline)

31st July 2007, 10:04	#10 (permalink)
UKSteve Still a novice... Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Jul 2005 Location: Weymouth, UK Posts: 557	Re: Tech.s to clear up fishnets entangled on a Wreck Quote: (Originally Posted by aquatiker) We want to remove the nets, considering the huge amount that has been covering the wreck turning it into a by-catch trap and within a few years really hazardous to divers. Can definitely relate to the by-catch aspect.. must be one of the saddest sights to see.. fish, turtles etc trapped in lost nets, fish pots etc. BTW ..if the wreck is fished regularly...watch out for hooks and monofiliment snagged in the net.. could be hiden under algae growth until you grab it with fingers... ouch!! Real snagging risk too. Again the knife is useless, slashers / shears essential..and placed where you can easily reach them (which is not generally the calf!!) Steve Last edited by UKSteve : 31st July 2007 at 10:12.
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