Rope Cutters

[Tranona]

Compared to the Stripper ... I think the gap is insufficient to allow the rope to drop in and get trapped / cut ...

The Stripper has tapered cutter blades specifically to allow the rope to get into the cutting area ....

Yes and crucially one blade is not fixed so it is not a scissors action.

That is a poor installation as there is insufficient gap between the cutter and the P bracket to allow water flow through the cutless. should be minimum of 15mm.

 

[Bandit]

I have had them on my Aquastar 48 for about 14 years we have also fitted them to many customers boats, yes they have worked on my boat.
Very efficient from a drag point of view. Negligible to no drag. The drag is effectively thr cross sectional area of your thumb in line with green water flow.
Simple.
Robust.

You need a quick cutter set, a nylatron thimble made to measure, it is normally a boatyard job to machine the thimble to size and fit. At the same time it is wise to drill prop boss to take a custom prop puller and to use rubbing paste and blue the prop to the shaft when you refit the prop.

Most other rope cutters cause significant drag at 16 knots and above think 0.5 to1 knot. Think what percentage of your fuel burn that is.

Some others cause significant cavitation to the prop.

 

[Jerbro]

Yes and crucially one blade is not fixed so it is not a scissors action.

That is a poor installation as there is insufficient gap between the cutter and the P bracket to allow water flow through the cutless. should be minimum of 15mm.

Thanks for the feedback.. I guess these are the kinds of products that you only know if they don’t work, not if they do. It fits my criteria of being better than nothing (according to the ybw review at least), and not having to drill into the p-bracket etc.. I’m a fan of keeping number of parts that live under water to a minimum. Ref. the gap, I think there is room to increase it, but according to the specs of this, and the other similar disc types I researched, they all recommend a minimum of 6mm (this one, the prop protector one and the R and D rope cutter).. I have a 10mm gap so I’m ok with it.. I haven’t noticed any performance degradation as I’m trawling around at 8-15 knots most of the time anyway (1500-2500 rpm at the prop through my 1:1 ratio gearbox!)

 

[Bouba]

Thanks for the feedback.. I guess these are the kinds of products that you only know if they don’t work, not if they do. It fits my criteria of being better than nothing (according to the ybw review at least), and not having to drill into the p-bracket etc.. I’m a fan of keeping number of parts that live under water to a minimum. Ref. the gap, I think there is room to increase it, but according to the specs of this, and the other similar disc types I researched, they all recommend a minimum of 6mm (this one, the prop protector one and the R and D rope cutter).. I have a 10mm gap so I’m ok with it.. I haven’t noticed any performance degradation as I’m trawling around at 8-15 knots most of the time anyway (1500-2500 rpm at the prop through my 1:1 ratio gearbox!)

I mostly go at six knots…but if I am going a long way I do ten

 

[westernman]

I mostly go at six knots…but if I am going a long way I do ten

And that is in the Tesla.

 

[jon and michie]

So which is the one most favourably to go for ?

 

[Tranona]

So which is the one most favourably to go for ?

Look around yards where boats are laid up will give you a good feel. Strippers far outweigh Spurs on shafts. Disc types are fairly common mainly because of the low cost, not because they are effective.

 

[Wakatere]

Look around yards where boats are laid up will give you a good feel. Strippers far outweigh Spurs on shafts. Disc types are fairly common mainly because of the low cost, not because they are effective.

I have a disc because there wasn't room for anything "better". The one time I got a rope over the side and in the prop it worked nicely.

 

[Bouba]

I have a disc because there wasn't room for anything "better". The one time I got a rope over the side and in the prop it worked nicely.

I’m glad to hear this...because it’s what I have

 

[Wakatere]

I’m glad to hear this...because it’s what I have

I should add - I've tried to learn my lesson and keep track of the free end of ropes. I no longer leave ropes on the foredeck if I think they'll reach the prop.

 

[Bouba]

I should add - I've tried to learn my lesson and keep track of the free end of ropes. I no longer leave ropes on the foredeck if I think they'll reach the prop.

I’ve only done that once...fortunately it was an outboard...so raised the leg out the water, sat on the swim platform...easy job
It actually takes a lot of mileage before you can convince yourself that you haven’t done any harm

 

[Tranona]

I have a disc because there wasn't room for anything "better". The one time I got a rope over the side and in the prop it worked nicely.

They are better than nothing but as tests have shown they are a bit hit and miss. You can often make room for a scissors type cutter by moving the shaft back with a spacer between the coupling halves

 

[Wakatere]

They are better than nothing but as tests have shown they are a bit hit and miss. You can often make room for a scissors type cutter by moving the shaft back with a spacer between the coupling halves

This is probably the wrong forum to go on about fin-and-skeg designs, but I'd have had to cut a chunk out of the rudder. Clearly what you say is true for some installations though.

 

[Tranona]

This is probably the wrong forum to go on about fin-and-skeg designs, but I'd have had to cut a chunk out of the rudder. Clearly what you say is true for some installations though.

No problem - that is why I said "often" - sort of assumed you might have a MOBO many of which have shafts on P brackets. Non fin boats are OK - photo is of mine with a Stripper and feathering prop fitted where a cut out of the (modified) rudder was necessary. Earlier boat of similar design also needed a cutout in the rudder. Appreciate that it is not possible/desirable to do this on all boats with limited clearance in the aperture