What causes “Fish hooks” in your Tow Wire?
If you have strained it you can break individual stands, sometimes hanging it up on the bottom. Also you can cause them by it wearing on the fairlead corners.
Usually the thimble on the wire is coming up on the vessel at an awkward angle or the gear used to retrieve the wire is inadequate,
on my vessel the wire is too long so it bends around the cleat coming on-board causing the fishhooks.
in order to keep a wire fishhook free the shipyard needs to create a “slope” similar to the anchor’s downward angle to get full use from a wire
coming back on-board the vessel
but that is not going to happen anytime soon.
PS, I just ordered a new wire yesterday…yes it has many fishhooks
Looking up the answer in my trusty brain, there are three main causes for fish hooks.
- Abrasion.
- Repeatedly running a wire around too Sharp a fairlead.
- Lack of internal lubrication.
So you can see that from the barge point of view the design of the opening where the wires must be pulled into is causing this: both abrasion and too Sharp an angle.
From the tug point of view, fishhooks usually come from slowing down too much while stteaming/retrieving the tow wire. This causes the outer layer to get worn down which causes either stress fractures or the actual contact with something on the bottom tears some strands.
But wire in all usage can be fishhooked from mis use.
In my experience a wire that has been lubed and is used with the proper sized (and workin) sheaves almost never gets fishhooks prior to being retired for expiration for ABS time limits.
How do you keep it properly lubed when the first four layers are in the water 12 to 15 hrs a day? We lube the tow wire once weekly but it just washes right off. The three bottom layers never leave the drum and are saturated with lube.
What baffles me is the fishhooks are on the first and second layer.
I’m trying to prevent this from happening again. I have cut off two and half layers and installed a new spelter socket. This wire was installed in Dec of last year. At 10k for a new wire I’m trying to get some life out of her. We are just fortunate that we don’t need a full drum to do the work we are doing now.
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Are you letting the wire out in the shallows? Also are you surging hard on the wire when it is up short?
No and yes. When we pay out we are in fairly deep water. As for the surging. Yes. When shorting up and the wire is short it will surge. Not So hard that it throws you off course but it does fetch up. Will that surging cause fishhooks?
It can, if you pull hard enough you can break individual strands. Also surging with a bad lead out of the levelwind on the winch will cut into the wire itself if it is out of the pins.
Might I ask where the wire was manufactured? Cheap wire is brittle wire. I really hope it isn’t Chinese? My experience with that crap is to just not go there in the first place but if you do have Chinese wire, plan on replacing it with US wire as soon as you can afford to do so.
.
And depending on use (or abuse), end for end will extend the life.
Most likely it is Chinese wire! Every tug I worked on that’s what we had!
Do you guys have a wire pendant or a chain pendant? When I was working in the Caribbean we had a chain pendant (half a shot) because it help with the surge. The bad thing about a chain pendant is that every time you break and make tow the weight of the chain puts extra ware and tare on the wire when compare to a wire pendant or a shock line.
Also if I remember correctly you guys are down in Puerto Rico (Beautiful island right?). I know all your maneuvering is done alongside with the wire over the bulwarks and that will add to the ware and tare.
Yes the island of enchantment!! I highly recommend you visit. As for where it was made. I don’t know. My customer supplied it at the beginning of the contract. But if your familiar with the local suppliers. It came from Astro Industrial. We do not flop around on it. We shorten up and let it go and make up in push gear on the fly. We use wire pennants off the scow shackled to a 10ft shock line shackled to our tow wire.
If memory serves me right. I was told once that if the fishhooks are sharp and pointy that is a indication they parted due to chaffing, abrasion. If the fishhooks are blunt and some what squared off on the ends that means they parted due to overload or stress. I don’t know how true it is or if it was ever true. I do know the fishhooks in our wire are sharp and pointy. Like they have been sharpened.
[QUOTE=tugboatchief;74275]If memory serves me right. I was told once that if the fishhooks are sharp and pointy that is a indication they parted due to chaffing, abrasion. If the fishhooks are blunt and some what squared off on the ends that means they parted due to overload or stress. I don’t know how true it is or if it was ever true. I do know the fishhooks in our wire are sharp and pointy. Like they have been sharpened.[/QUOTE]
You got the square deal on that chief…look at all the rest of your wire in the area near where the fish hooks are and you’ll see the chafing. You say the problem is only the first two wraps or two turns (ie. fish hooks over more than a couple of hundred feet or only the first 40’ or so? I assume you have a stern roller free to turn easy under the weight of the wire and pennant? Are you allowing the wire to run right on top of the bulwarks aft? If the problem is close to the socket your bending and abrading the wire bringing it in I’d venture to guess.
btw, my understanding of wire rope construction is that the strength of the rope is carried in the inner strands and the core not on the outer strands. A few fish hooks on the outside doesn’t mean a rope is bad but if you open up a nice shiny rope and find the inside all rusty with no lube in there then you have a problem. Lube well and lube often.
Once in Thailand a young woman told me the exact same thing. Lube well and lube often. She was very friendly and very helpful. Ah the memories
Yes you are correct. Roller with pin system and the fishhooks start 200’ft from the thimble and continue up another 300ft.