Ropecutters: more trouble than they are worth?

Danny Jo

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Freestyle sailed into Loch Foyle three weeks ago and was caught in a salmon drift net. Less than 30 minutes later another yacht sailed in and was caught on another. (Yes, I thought they were illegal too, but apparently fishermen on Loch Foyle have a special dispensation to use them.)

It was blowing around 18 kts from the northwest. Furling the genny was easy, but getting the main down when you are tethered by the stern is something else. Fortunately I had a reef in, and I hauled up the boom on the topping lift, but like a fool I eased the main sheet, until the penny dropped and I sheeted it in hard to reduce the windage. The crew were all for cutting the net, but I reckoned that so long as I was attached to a valuable bit of fishing kit I stood a reasonable chance of getting a tow into harbour, and so it proved. Tied up in Greencastle, I took a look underneath, found that the float rope had a half-hitch around the propeller, and was free in less time than it takes to consume two lung-fulls of air.

The other crew wasn't so lucky, because they had started their engine before fouling their net. I and the other skipper both had a go at cutting it off, and managed to cut away enough rope to turn the prop, but could not clear the mass of fine netting. The diver engaged to cut it all away came up with bad news - the bronze cutlass bearing housing (to which the fixed part of the boat's serrated, scissor-type ropecutter was attached) was rotating freely in its own housing, another bronze fitting glassed into the hull. The cutlass housing was supposed to be screwed into the hull fitting, but the thread had been stripped.

My view is that this boat would have been a lot better off without a rope cutter. To the cost of the diver, the rope cutter has added the cost of a specially hired crane and some expensive work to rehouse the cutlass bearing into the hull.


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Possibly or maybe he should have had a different cutter? but I would say that.

We haven't seen any shaver cutters broken from their mounts in four years of supplying them to commercial fishing boats and only one has needed spare parts in that time.

In some ways he may have been lucky as we have seen two boats where the gearbox has been pulled of the engine after catching debris.
 
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Wouldn't be without mine. Here is a little bit of net that I caught in the North Sea.

I have felt a dull thud several times, and seen fine evidence of rope fouling on my boat.The only dmage was a nick out of one of the Zytel blades on my Kiwiprop, and I really heard that one. Quick bit of fairing off and its perfect again.
 
You do seem to have been unlucky. My Stripper works fine, certainly on a genoa sheet, not sure about netting as I don't think I've ever tangled with any.
 
Unguarded drift nets deserve no mercy. Rope cutters generally work well and I wouldn't be without one. Got us out of trouble twice so far.
 
When I didnt have a rope cutter it cost the insurance company nearly £3K, engine/gearbox damage plus all the labour. Since I installed a rope cutter I've never seen another rope, or have I?
 
Even after they have cut a rope or net you can have a bit left wrapped around the shaft or even between the blades, but at least damage has been avoided and you can get home. It worked so well one year I didn't even realise we'd caught a rope during the season until our lift out for the winter, and a short bit was still wrapped around the shaft.
 
cost shouldnt be an issue. if the net was unmarked and in a fairway, sue the fisherman through the small claims court. I wouldnt hesitate.

isnt that boat one of these expensive Swedes. Doesnt sound so well constructed if that can happen.
 
My view is that this boat would have been a lot better off without a rope cutter. To the cost of the diver, the rope cutter has added the cost of a specially hired crane and some expensive work to rehouse the cutlass bearing into the hull.

That's why we pay insurance :)

Having seen them in action during our rope cutter test, I wouldn't be without one ;)
 
cost shouldnt be an issue. if the net was unmarked and in a fairway, sue the fisherman through the small claims court. I wouldnt hesitate.

isnt that boat one of these expensive Swedes. Doesnt sound so well constructed if that can happen.

The nets were possible to see only from within a 20 metres or so. The owner of the one that netted Freestyle said "Didn't you see me waving?" I replied that I was concentrating on the ferry whose path I was about to cross. Having towed me in, the net owner and I parted on amicable terms, but, again, the other boat wasn't so fortunate. His netter kept pestering him for 200 Euros for damage to his net.

Yes, I think that the boat was a Swedish-built one.
 
I have an Ambassador rope cutter. On our last trip in Mallorca it sliced through the marina's bow line that was probably 40mm rope! I would not want to be without it now

Tudorsailor
 
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Wow! Ten out of ten respondents refute my suggestion.

Can I claim a first?

Difficult to see what is wrong with the stern gear on the boat - but it should never unscrew! Normally it is screwed up tight and then has locking screws/bolts to stop it from turning. One of the strongest bits of the boat which is why you can anchor the fixed cutter striker block to it.
 
What actually happened to the cutter? and why.

It would be intersting to see what state the cutters fixed and rotating blades were in after this incident. If the net had caught a prop blade and was winding up on the shaft aft of the rotating blades fitted to the shaft, the net is likely to have exerted considerable pressure on these blades trying to push them forewards before any net would have gone between the blades of the cutter. Could it have been this build up which then resulted in the large force forewards and rotating to damage the bearing carrier?

Was the fixed blade damaged, were the fixed and rotating blades still running with a close tolerance enabling them to cut efficiently?

Analysis of this failure could be quite useful.

Seeing as there is a link to the MBM test, here is a link to the shaver cutter test. Notice that the debris is fixed at the prop blade and winds on the shaft/spool.

http://www.youtube.com/watch?v=Qh9SnDzXJXk

The shaver was not included in the mbm test because the test involved fixing one end of the debris to the P bracket and letting the loose end wrap on the shaft. The debris whilst loose, went around with the shaft for a few turns until the slack was taken up, it was then either pulled apart with the help of being tight over a rotating sharp disc or being pulled directly into the path of the rotating blades. The shaft works like a winch drum winding the debris on until there was no slack.

In some cases the shaft continued to rotate under the few turns of debris .

In essence the rope was fixed in relation to the rotating shaft,blades and discs.

The cutters rotate and in this test the debris was fixed.

The shaver cutter works by shaving away at the rope as it winds on the shaft having been caught by a prop blade (rope is rotating with the shaft) so this test would not have shown what happens when rope is caught by a prop blade (fixed at the prop and pulling up slack from the sea bed or winding in a net horizontally)

The cutter is fixed and the debris rotates.
 
Analysis of this failure could be quite useful.



It would indeed. However, if you read the post carefully, the cutter did not fail, but the cutless bearing housing thread stripped allowing the housing to turn. The fixed cutter would then no longer be fixed! If the thread did strip then he has more problems than just picking up a net!

Perhaps the owner (rather than an observer) will read this and give us his story.
 
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