Rope cutter- any thoughts?

[Crinan12]

Hi all another question from me sorry

I read about these rope cutter things and watched a few videos- they look amazing. I assumed due to relatively low cost and potential to save a major headache almost everyone would have one. So I was surprised to see none at the boat yard at Crinan had one fitted. Am I missing something? I wondered what the general consensus was. Are they not as good as they look?Or is it just rare to get something wrapped round the prop?

I was going to fit one to my shaft assuming I have room. I seem to have about 60mm of shaft avaiIable but i need to get an anode on there as well so perhaps it's a bit tight for space.

Thanks

 

[LadyInBed]

[FONT=Open Sans, sans-serif]There looks to be space to me, move the anode tight upto the prop.[/FONT]

 

[Sticky Fingers]

They're not "low cost" and "amazing" at the same time.... I've got one, it was £1500 plus VAT fitted. It's an Ambassador Stripper, on a 3 blade Volvo folding prop. Volvo D2-60.

http://www.ropestripper.com/

So far, no prop wraps, so either no rope anywhere near the prop, or it works.

 

[Gerry]

We have 'The Stripper'. It has been invaluable on a number of occassions. To our knowledge it has cleared lines at least a dozen times over the past twenty years. From fairly small ropes to substantial lumps of fishing net. Wouldn't be without it even though it is quite expensive to fit.

 

[Crinan12]

Hi Gerry. What's involved in fitting?I thought they just bolted to the shaft?Thanks

 

[macd]

What's involved in fitting?I thought they just bolted to the shaft?Thanks

Some do, but they don't work very well. The more effective ones, including the Stripper (mentioned above) have a rotating blade element on the shaft plus a fixed blade, the two acting against each other. Obviously the fixed blade takes a little more fixing than the one on the shaft.

PBO did a test on several types a few years ago: the single, disc-type were rubbish, the fixed+rotating blade types good. The Stripper, if I remember correctly "chopped through everything we threw at it".

 

[Heckler]

Hi all another question from me sorry

I read about these rope cutter things and watched a few videos- they look amazing. I assumed due to relatively low cost and potential to save a major headache almost everyone would have one. So I was surprised to see none at the boat yard at Crinan had one fitted. Am I missing something? I wondered what the general consensus was. Are they not as good as they look?Or is it just rare to get something wrapped round the prop?View attachment 76845

I was going to fit one to my shaft assuming I have room. I seem to have about 60mm of shaft avaiIable but i need to get an anode on there as well so perhaps it's a bit tight for space.

Thanks

If you do anything, make sure you dont block the entrance to the cutlass bearing! It needs water up there to cool the seal and bearing.

 

[NormanS]

Be aware that if your propeller thrust is taken by the engine, rather than a thrust bearing, and if, like many, your engine is mounted on rubber mounts, the engine will move ahead when in forward gear, reducing that 60mm considerably.

 

[PhilipH]

Another vote for the Stripper - saved us on two occasions. Service kits also available at reasonable cost.

 

[RupertW]

We have never had one on 4 boats and decades of sailing. I’ve wished I did have one maybe 4 times over 30 years, with a lot more occasions where a quick burst of reverse has removed weed or other obstacles from the prop.

Those 4 occasions required me to go down with mask and bread knife - twice it was a pleasure, twice a chilly chore.

I now sail in warm waters where I dive to check the anchor every time - as much for fun as necessity so currently no inclination to fit one for such a rare event that is fairly easily solved. But that’s my choice - and if I wasn’t spending so much on fridges and ice makers as a priority it would eventually get to the top of my spending list.

 

[Norman_E]

The plain disc type work perfectly well, if you do the right things. Firstly they have to be sharp because they work by the propeller pulling the rope tightly against them, not by rotating against it as some people seem to think. Secondly if caught on a rope and the engine stalls, simply restart in neutral, and go backwards and forwards until the rope is severed. I have several times posted photos of a big tangle of rope, mostly 16mm braid on braid, that was sucessfully cut away by mine. The expensive and complicated ones need to have a part attached to the P bracket, where there is not much metal to tap in to. There have been cases of the fixed part being torn off by the forces involved.

 

[ghostlymoron]

I've read somewhere that RNLI have the sharp disc type. I've only got rope round my prop once and that was my own mooring rope! whilst leaving my tidal mooring. I just waited for the tide to go out and cut it off with my sailing knife.
To the OP I'd say fit a disc cutter and replace your anode - it looks about shot.

 

[JumbleDuck]

Be aware that if your propeller thrust is taken by the engine, rather than a thrust bearing, and if, like many, your engine is mounted on rubber mounts, the engine will move ahead when in forward gear, reducing that 60mm considerably.

Also you have to leave a reasonable amount of space behind the cutless bearing for water to get in and lubricate it.

 

[Gerry]

Hi Gerry. What's involved in fitting?I thought they just bolted to the shaft?Thanks

Not to fit but to buy! Sorry it was early....

 

[Neil_Y]

I've read somewhere that RNLI have the sharp disc type. I've only got rope round my prop once and that was my own mooring rope! whilst leaving my tidal mooring. I just waited for the tide to go out and cut it off with my sailing knife.
To the OP I'd say fit a disc cutter and replace your anode - it looks about shot.

The RNLI use the QuicKutter which we supply, as do many commercial and fishing boats.
We also supply the US Navy, Christensen Yachts, Fleming, Baltic Workboats, Aquastar, Ali Cats to name a few.

 

[capnsensible]

Have had several occasions to be grateful for them being fitted on a number of yachts Ive sailed. Top idea.

 

[Neil_Y]

Rope cutters, there are three distinct types.
Scissor - Spurs,Gator,stripper a fixed blade (bolted to bearing carrier) and a number of rotating blades (clamped to shaft) acting as scissors do.

Disc - shaft shark is one a sharp edged or serrated disc clamped or bolted to shaft


Shaver - quicKutter a fixed blade attached to bearing carrier (works like a lathe tool) and a spool bolted to prop to act as a winch drum. The RNLI used to use Scissor cutters (Spurs) but changed to the shaver QuicKutter many years ago.

 

[vyv_cox]

You need to ensure there is sufficient meat in the bearing housing to hold the fixed blade of a Stripper when a heavy shock load comes on it. Modern P-brackets have quite thin walls and I have lost two fixed blades when the threads simply pulled through. Ambassador make an additional bolted ring that provides extra strength in this case.

Since I lost them I switched to a Proprotector, which was not described as 'rubbish' in the YM test, just not quite as good as the Stripper in a couple of special cases, e.g. copper wire.

 

[Neil_Y]

You need to ensure there is sufficient meat in the bearing housing to hold the fixed blade of a Stripper when a heavy shock load comes on it. Modern P-brackets have quite thin walls and I have lost two fixed blades when the threads simply pulled through. Ambassador make an additional bolted ring that provides extra strength in this case.

Since I lost them I switched to a Proprotector, which was not described as 'rubbish' in the YM test, just not quite as good as the Stripper in a couple of special cases, e.g. copper wire.

Very true Vyv, one of the problems with the scissor idea, huge shock loads, especially if there is a fish hook or any metal like a wire trace that finds its way between the blades.

 

[Neil_Y]

In terms of space required, with a soft (engine on rubber taking thrust loads) drive set up we suggest you allow for 18mm total shaft movement and 3mm min for water to exit shaft bearing. Thus equals a min gap if 32.00mm with the 20mm spool final gap is 12mm but the anode needs to be moved to a prop nut anode. To be honest on the smaller engines the engine normally stalls before significant damage is done. On bigger engines with big reduction gearbox you can pull the p bracket out or pull the gearbox off.