Sailing Today did a group test a few years ago. In broad terms, dearest came out best. Results ranged from 'cut through everything we threw at it' to completely ineffectual. Can't recall the trade name, but the latter was the simple disc-type device. The types that rotate shaft-mounted blades against fixed blades seem the most effective.
My Ambassador works: someone let a mooring line (20mm double braided) hang in the waters and it got wrapped round the propeller. In very short time (apparently theye did not have time to realise what had happened!) we had a free propeller /forums/images/graemlins/smile.gifand lost a couple of meters of new mooring line /forums/images/graemlins/crazy.gif.
It seems to work, but cost me half as much as the new propeller.
My Ambassador works. AFAIK it was only the once. I was about to leave Brest, when there was a great thumping and bumping under the boat. I disengaged the engine and it stopped. I wondered if I had a problem with the prop. so arranged a lift (cheap at Brest €40). I was v careful going into the hoist, engine dead slow - no thumps and bumps - then lifted. I was a bit surprised to see big marks on my rel. new antifouling, like someone had swept something across it. Later, I met the person who had accidentally left a 16mm mooring rope dangling... it just had this messy end, as if cut with a blunt hacksaw! The marks must have been where the prop was sweeping this hawser around, before or during the cut.
The Ambassador or Spurs always come out best in tests by the boating mags - circular 'knife' type appear to be pretty useless but much cheaper of course!
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The Ambassador or Spurs always come out best in tests by the boating mags - circular 'knife' type appear to be pretty useless but much cheaper of course!
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Just to keep you up to date, THIS rope cutting system was developed after Keith Colwell's rope cutter article.
My rope cutter was fitted 12 years ago by Harold Hayles in Yarmouth IOW by the previous but one owner.
Last year got fouled by a rope of Cowes IOW, which stopped the engine. On restart everything fine - so it did its job.
On haulout this year found that the fixed bit attached to the hull was not longer there. Spares are available so it will be re fitted this winter. The make is Spur, and it worked for me!
I have spur cutters. The most they have dealt with that I know of was a hard laid leaded 25mm.
I did lose the whole thing when I picked up some Spanish longline, about 200 m in a lump, and have lost the V block on another occasion.
They are only as strong as the Allen screws holding the 'V' block on the stern tube. After losing this I redrilled and upgraded the size. That was ten years and ten thousand hours ago.
A friend is pleased with the C&O Engineering disc type: I think you have to rely on getting the stuff wrapped around a bit to cut it, or get an end aboard and make fast. Great thing is, no moving parts.