Net Removal On the Georgia Straights

[Blackwood]

--- Note: the following is a repost. Original by LimeyX on divematrix ---

Mark Blackwood, Tobia Enhus, Ari Shofet and mysefl joined Kurt on the Clearwater today to try to remove some fishing nets from the Georgia Straights.

The wreck is in about 80 feet of water off of San Pedro. Kurt and his teams have worked it before, but it was the first time for us divers. We had a little bit of footage from previous dives to watch on the trip out to the site.

In all, we did two dives with about 50 mins bottom time on each dive.

This net is really embedded on the wreck, and you have to fight for every inch of it.

Vis was a decent 10-15 feet, rapidly dropping to zero as we started to cut.

We definitely need to rethink our tools.

We started off with Z-knives, but they just dont cut it (pun intended) for thicker net or bunched up net.

One of the more effective ways we found was to roll up a bunch of net into a "tube" and cut with a serrated knife.

Tobias and Marc spent a lot of effort cutting through some very thick rope which may have embedded metal. What are these fishermen thinking ?

In all, we only got around 30 pounds of net off, but it was not for trying.

A few shots.

 

[ligersandtions]

Thanks for all the hard work, Marc! I think what you guys are doing is remarkable....it's so sad to see critters get caught up and die in nets. It's great that you guys are doing what you can to eliminate this issue!

 

[Teamcasa]

On behalf of the rest of us, thanks for doing the work.


Just a fleeting thought on removing the net. What if you connected several small lift bags to different points on the net and floated it up and cut the attachment points?
Just thinking aloud.

 

[JeffG]

Just a fleeting thought on removing the net. What if you connected several small lift bags to different points on the net and floated it up and cut the attachment points?
Just thinking aloud.

Could get ugly as an entanglement. Personally, I would always want the net to be below me.

 

[limeyx]

Thanks for reposting Marc! Now we just got to get back there for another go!

 

[Blackwood]

On behalf of the rest of us, thanks for doing the work.


Just a fleeting thought on removing the net. What if you connected several small lift bags to different points on the net and floated it up and cut the attachment points?
Just thinking aloud.

Could get ugly as an entanglement. Personally, I would always want the net to be below me.

Good thinking, and while it may work in some situations I'm not sure how well it would apply to the big mix of entangled, ensnared (to use Nick's word). Whatever we managed to lift would still result in a huge volume of connecting net to cut (the 6th photo is a good example).

At one point, Tobias was standing flat footed (finned?) on the bottom and pulling with all the strength he could muster to try and identify a cut point. He didn't make any progress other than to create a silt plume that reached 18 feet and zero out the viz on the bottom to the point that we could no longer find where we had been working (so our second dive was a wash, hence only three sacks retrieved).



That said, I agree with Jeff's assessment. When we went after the Caissons (different layout, net is draping over the side like, well, drapery), the plan was to start from the bottom and cut up vertically before bundling and making a horizontal cut to free the big burrito of net, idea being to never have loose nets above divers. The Caissons are in 150 feet of water, so entrapment is much more severe than on this wreck (80 feet), but it's still a major concern. If current picked up in midwater, or for whatever reason the bag failed, or if cutting some of the attachment points allowed the rest to give way under the buoyant load, nets moving around out of control could pose a major problem.

Personally, if we end up "brute forcing" it, I think I'd rather go connect a bunch of the net to a winch and see if we can get anything up (without just ripping through the net) that way. In other words: all divers out of the water before the nets start going up.

 

[MaxBottomtime]

Part of the problem with winching is that you need four anchor points for the boat, otherwise any spin would likely tangle the net on another spot of the wreck. I have used liftbags to remove nets many times and was able to bring up more net with two or three divers than four teams bagging pieces on the bottom.
As far as the Georgia Strait goes, it would be best to have two divers use a few liftbags with forty feet of line attached between the net and liftbags. If the net became free unexpectantly and trapped a diver it would only rise about twenty feet above the wreck. After filling the bags with just enough tension to make the net taut, the two divers would then work as safety divers for the cutting teams. No bagging, no uplines to clip bags to and minimal cutting involved (only the points where the net is caught. Also, the cutting teams would be working mostly on the perimeter of the net rather than above it. With the limited bottom time on the wreck it would be nice to bring up a few large pieces each dive than a couple bags.
The last time I was there I was able to cut the entwined ropes with the steel cable using only my EMT shears and a pair of cheap snips from Target.
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[Teamcasa]

...the cutting teams would be working mostly on the perimeter of the net rather than above it....

That was the direction I was thinking.

 

[MaxBottomtime]

When Ross discovered the abandoned gill net a couple of years ago we planned to bunch it up. Merry and I dived from Marc Bacon's boat while Elaine Jobin and Jeff Shaw dived with Ross. Merry, Marc and I dropped and found a trawl net covering a nearby reef. I attached a single liftbag, then Merry and I cut away the snagged net. We brought up the entire net in only fifteen minutes.
On the Fog Wreck, Ross, Merry and I used two liftbags, then began cutting the perimeter of the net. We had just finished one side when the net broke free and went to the surface. We didn't get as much as we wanted, but you can see how much three divers can do on one dive.