Rope cutters that work!

I have an ambassador ropecutter on a very short stub on a perkins 4108. The only time i realised i'd hit a rope was whan we got an 18mm anchor warp under the boat and into the prop. The cutter parted the rope with a single thump. Engine was in gear but barely above tickover.

Have not found any other ropes, at least never had a fouling problem. Maybe because it works, maybe because that once was the only time I'd hit anything!
 
I have a Quickutter as distributed by H4 Marine , not only are they simple but they are very low drag ( less fuel), minimal production of disturbance and cavitation on the props and very simple.

Some of the sharpened discs and the rotating blades generate a lot of drag ( fuel wasted) and cause significant cavitation to props.

However QuicKutter are more expensive to fit but I probably saved that in fuel in the first 40 hours on saved fuel.

I rate them.
 
From memory a scissor type rope cutter came out best in the YM test.

I used to have one and found it effective but to mind it suffered from one draw back. On my boat, when actually cutting a rope it seems quite strain is placed on the cutter, one half of which is fixed to a a soft bronze P-bracket. The result was that the rope cutter was knocked out of adjustment resulting in a maddening clicking as the scissor blades touched on rotation thereafter.

Yes - the fixing screws ran be re-tightened but I subsequently found that anything less than perfect adjustment meant more clicking, as did a new flexible coupling, or another rope contact.

I have subsequently changed to a disc cutter because its simple and robust, but that said its too soon to provide any honest practical feedback.
 
silver-fox said:
From memory a scissor type rope cutter came out best in the YM test.

I used to have one and found it effective but to mind it suffered from one draw back. On my boat, when actually cutting a rope it seems quite strain is placed on the cutter, one half of which is fixed to a a soft bronze P-bracket. The result was that the rope cutter was knocked out of adjustment resulting in a maddening clicking as the scissor blades touched on rotation thereafter.

Yes - the fixing screws ran be re-tightened but I subsequently found that anything less than perfect adjustment meant more clicking, as did a new flexible coupling, or another rope contact.

I have subsequently changed to a disc cutter because its simple and robust, but that said its too soon to provide any honest practical feedback.
Click to expand...

+1

Disc cutters are simple effective mechanics. Gets my vote every time.
 
When you next take your prop and rope cutter off, put the prop narrow end of taper on the ground than place the disc or blade cutter over it as if the shaft was in place.

You will see better the disturbance that the cutter is likely to cause and then imagine the cavitation.
 
We have had both scissor and disc types on various boats over the years. Have found both types roughly equally effective. This is judged by bits of rope and, on one occasion, the remains of a life vest found hanging around when the boats were lifted! We assumed the life vest was unoccupied at the time of impact!

We had one failure of the scissor type when we encountered a large amount of fisherman's netting off Nieuwport, Belgium. In fairness there was so much of it that no cutters would have been effective. The impact sheared three of the bolts securing the fixed end of the cutters but fortunately didn't cause any other damage.

Richard.
 
Spurs, had them on two boats. There are other scissor-type varieties but probably not much in it. Yes you may get cavitation, I don't at shaft speed max 800rpm, when I had a fast boat with 1:1 drive and a sandy harbour they wore out, but I didn't notice any cavitation. I have twice broken these in twenty years, about 20,000 hours engine time, once took the holding block off the stern tube (large coil of 12mm) and this year broke a blade off. Usually don't even notice the cut until I see bits floating astern. My friend has the rotating disc type, he likes it, but he has to make fast the end of what's in there to be effective
 
If you have spurs or similar rotating blade cutters it is s good idea to clean the blades and to replace the plastic bearings/ separators each year so the blades do not touch each other.
 
Bandit said:
If you have spurs or similar rotating blade cutters it is s good idea to clean the blades and to replace the plastic bearings/ separators each year so the blades do not touch each other.
Click to expand...

Yerbut, I haven't had to replace the spurs bearing on this boat for many years, perhaps twice in twenty years/20,000 hours, but with a faster drive and/or a sandy environment it could be more than once a year.
 
Bandit said:
I have a Quickutter as distributed by H4 Marine , not only are they simple but they are very low drag ( less fuel), minimal production of disturbance and cavitation on the props and very simple.

Some of the sharpened discs and the rotating blades generate a lot of drag ( fuel wasted) and cause significant cavitation to props.

However QuicKutter are more expensive to fit but I probably saved that in fuel in the first 40 hours on saved fuel.

I rate them.
Click to expand...

And me. Saw no difference in speed when fitted and used it in earnest last season... and it worked
 
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