Do I take them off or not?


Active member
19 Aug 2001
Brecon, Wales
My boat is fitted with rope cutters.
I understand they cost me about 2 or 3 knots and hence about 10% in extra fuel costs.
If I remove them I gain speed and effciency.
If I leave them on - just what protection do they really offer - experiences and advice needed.



16 May 2001
UK -Berks
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Who says they cut your speed that much? The RNLI say they gained a ½ knot. My previous boat I noted a gain of a ½ to a whole knot too.
If you are that worried about speeds try reducing the weight you carry, for one don't go to sea with full water tanks, run it all of except a few gallons, ditch unneccessary fenders, ropes and anything else. Weight is a far more adverse factor than the doubtful effect of Cutters. A slightly dinked prop can knock your speeds down massively. There are many many things of more concern than Cutters.



21 Aug 2001
South East England
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A good few years ago I was in the police crew that took delivery of the first Thames based boat fitted with rope cuters. 2 hours later we were winched out at Wapping with, You guessed it. A rope around the prop. IMHO they are not worth the sweat used to put them on let alone a couple of hundred quid to buy them. Much better to keep a good watch and avoid the flotsom. By the way Byron's advice is about the best you'll get.

Best of luck

ChrisP :)

Deleted User YDKXO

For what its worth I have removed the Spur cutters fitted to my boat and gained an extra 2-3 knots speed without changing anything else. I know somebody else who has had a similar experience. Yes, I have also heard the story of the RNLI boat gaining speed but I think you'll find the general concensus is that cutters will lose you some speed. Also, I've heard that cutters will not remove everything and if they cannot cut whatever is around the prop, then they only make it even harder to remove the tangle.
You have to weigh up the risk of total disablement against the extra cost of buying the cutters (around £500) and the extra fuel cost
Personally and I say again IMHO I dont think its worthwile for a lightly used leisure boat to have them fitted although for a commercial boat, its probably different. I've experienced prop fouling a number of times but its always been one or other not both and I think you have to be really unlucky for both props to be totally disabled and, if that happens, you have to ask yourself whether cutters would have helped anyway
In your case, since you already have the cutters fitted, its probably worthwile removing them the next time the boat comes out of the water and testing what effect that has. If it has little effect on speed then keep them


IMHO I would leave them on as they are already paid for get the sea miles in then decide as you are gaining confidence all the time it is nice to know they are there if needed, if you are loosing a bit of speed in the summer then spend a little money on a mid season scrub, it is surprising what effect it makes, here is my example,
had boat out end april last year, cruised to France end may, beggining of june, noted speeds and mpg etc, came to go for summer holiday had trips out before noticed speed down etc, just before start of hols had a quick lift and wash, £60 at marina, made the whole cruising a lot better, no sooty transom etc as there were 6 of us on board and all the gear for 2 weeks, think about it.

Paul js.