Propeller Rope Cutters
Printed From: myHanse.com
Category: Hints & Tips
Forum Name: 345/348
Forum Description: 345/348 Hints, Tips and News
URL: https://www.myhanse.com/forum_posts.asp?TID=8689
Printed Date: 27 March 2026 at 03:51
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Topic: Propeller Rope Cutters
Posted By: monty7442
Subject: Propeller Rope Cutters
Date Posted: 20 October 2014 at 22:14
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Hi All I'm considering fitting a rope cutter to the prop this winter. I have never had one and never actually had a fouled prop but maybe I've just been lucky. I have a folding 2 blade flexofold - any experiences or recommendations as to the best one would be appreciated.  ------------- Monty |
Replies:
Posted By: samuel
Date Posted: 21 October 2014 at 08:21
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On my saildrive I have a stripper from Ambassador marine. I am told that it is the only one that can be used on a saildrive. But by all means check that statement first. Mine has 2 No. 5mm bolts that hold the 2 main parts together. The heads of the bolts locate in pre drilled holes in the back of the propellor. However, these bolts have sheared every year & i replaced them by drilling the hard steel & re threading & using 6mm bolts. I am told the later strippers use 3 bolts to counter the shearing off. This means that when you get the stripper you then have to have holes drilled in the back of the prop to take the heads of these bolts. ( The bolts are actually Cap Head type for allen keys). These holes need to be very accurate as they need to apply the same shear on each bolt head. if one engaged first it would shear that one , then the next one to engage & so on. My Brunton Auto prop had the holes ( 2 ) drilled when it came as I bought both items from Brunton. When i sent the prop back for service Bruntons drilled 3 more holes as I thought I was going to have to buy a new stripper. The reason i expected to buy a new stripper was because the bearings ( thin shims of some thing like Delrin or similar) had worn & the metal began to wear so much that the standard shims would no longer fit & it allowed a gap between the cutting blades, ( they pass close to each other like a scissor). When i rang Ambassador I had the impression that it was a bloke in his lounge making up prices. First he wanted £500-00 for a new stripper, Then he reduced it to £480-00 then he reduced it to £ 450-00. New bearings are about £ 55-00 ( depending on whether he has had a bad day or not I suspect). i was so P..d of with his attitude I paid £ 28-00 online for some tuffnol & made my own shims on my lathe to suit the worn blades. The stripper now works fine. So you need to check the bearings every year & change them in time so you do not wear the steel as I did. You also need a slightly different Anode as the stripper fits into this. Once again I got fed up with the price & I now buy standard saildrive anodes & drill the required hole & cut the required groove myself Buy one plus a standard one & then alter a standard one for yourself using the new one as a guide before you fit the original one which will get worn & you will not be able to use it as a guide Finally make sure the shaft on the saildrive is long enough to accept the stripper as it pushes the prop aft a bit. As to performance. I have hit something every year & got away with it most times. I have cut nets & ropes but most years I have hit things that are so thick that the bolts have sheared. But I have still got away with it. It cuts rope up to 25mm with ease. Plastic bags are the worse but go eventually ------------- Daydream Believer- Hanse 311- No GBR9917T- Bradwell Essex |
Posted By: echoofwight
Date Posted: 21 October 2014 at 08:59
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Hi Samual, I am interested in your experience with your rope cutter, I have the same stripper with a Volvo saildrive and Volvo three bladed prop. I am now up to over two thousand engine hours and several thousand sailing miles. I have no problems. It has chopped through ropes and at least one sack. I take it apart every year and change the bearings every two. I wonder why the bolts shear on yours and not mine. Interesting. Steve ------------- Steve. Hanse 341 Echo of Wight, . Deep draft and rudder, white hull, Single aft cabin. Raymarine instruments. Raymarine radar. Garmin AIS. Wheel Steering, Portsmouth. |
Posted By: monty7442
Date Posted: 21 October 2014 at 09:56
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Blimey I didn't know it was going to be so complicated. But thanks for the insight Samuel. Are there any other experiences of rope cutters on the 2 blade Flexofold prop? ------------- Monty |
Posted By: samuel
Date Posted: 21 October 2014 at 11:18
As i said, later models have 3 bolts & I think that for a while they had 2 No. 6mm bolts in lieu of the 2 No 5mm that I had. I generally knew when they sheared because I felt the thump as they caught something & then, possibly because the shims were worn the blades rattled . At the time I did not know about changing the bearing shims. But now I have a few spares. However, after my round UK trip I think that the grade of tuffnol I used may have performed better than the manufactured ones. They certainly cost a lot less. I am ashamed to say that I have now clocked up at least as many hours as you have, Possibly 3000 !!!! ------------- Daydream Believer- Hanse 311- No GBR9917T- Bradwell Essex |
echoofwight wrote:Posted By: High Time
Date Posted: 21 October 2014 at 20:40
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I had an Ambassador rope cutter on my previous boat for 13 seasons (10,000 miles and 1500 engine hours) without any major problems. I replaced the nylon(?) bearings (shims) after 10 years and, like Samual, modified the standard anodes to fit. I reckon the cutter did it's stuff probably 3 times before I sold the boat. I specified the same for High Time and so far (2 seasons) I have nothing to report. I haven't had to replace the bearings or anode yet and haven't felt the cutter 'operate' (yet). However, it's good to know it's there! Well worth fitting, though, just for peace of mind, even if it doesn't ever perform it's primary function.
------------- Roger High Time (415 #038) |
Posted By: samuel
Date Posted: 22 October 2014 at 05:46
This is a thread drift !!!! 1500 hours at 6kts ( which is roughly what most of us get) is 9000 miles If you allow for motoring in & out of port etc then say 5Kts & that is still 7500 miles If you only did 10000 miles then that leaves 1000 miles ( or 2500) of sailing I was surprised after my last season to see how many hours I had clocked up under engine Made me wonder if I had a motor boat or a yacht It makes claims of only motoring a small percentage of the time difficult to substantiate ------------- Daydream Believer- Hanse 311- No GBR9917T- Bradwell Essex |
Posted By: echoofwight
Date Posted: 22 October 2014 at 09:43
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I think it depends on where you sail, I often need to run the engine for an hour to get to a point I can sail from, with the best will in the world I can't sail through a lock. Then a short sail to Cowes, or somewhere else close and the engine is back on again. ------------- Steve. Hanse 341 Echo of Wight, . Deep draft and rudder, white hull, Single aft cabin. Raymarine instruments. Raymarine radar. Garmin AIS. Wheel Steering, Portsmouth. |
Posted By: High Time
Date Posted: 22 October 2014 at 13:11
Definitely thread drift and I'm not sure what point you were trying to make. There was some rounding in my figures - now I think about it the engine hours were probably nearer 1200 and quite a few miles were missing when the log stopped working (as it did frequently). However, I make no apology for the miles to engine hours ratio. I suspect many other owners have similar ratios. I sail mainly with my wife as crew. She likes 'yachting', which starts when the sailing stops! This means that passage making is achieved as quickly and painlessly as possible. It's a compromise but at least she comes with me. I note that you sail mainly single handed where you have only yourself to worry about. Also, much of the mileage is achieved on long summer cruises - several down to south Brittany, as far as La Rochelle. This sort of passage making often has significant tidal gates and frequently necessitate motor sailing to maintain the required average speed. Finally berthing in a locked marina requires prolonged use of the engine for little distance covered. Please don't feel ashamed of your 3,000 engine hours - I am sure you have equally valid reasons.
------------- Roger High Time (415 #038) |
Posted By: samuel
Date Posted: 22 October 2014 at 18:38
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Please- I was not knocking , only making an observation on something that sprang to mind when I read your post ------------- Daydream Believer- Hanse 311- No GBR9917T- Bradwell Essex |
Posted By: CharlesP
Date Posted: 23 October 2014 at 10:23
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And getting back to the thread, I have had four seasons with my Ambassador Marine cutter on my two blade fixed prop, on a Yanmar SD20 saildrive. It cut through a thick fishing net line on my recent Summer cruise. The engine slowed considerably while it munched through the rope, so must have been quite thick. You don't notice it cutting thin lines, but sometimes their short ends stay around the saildrive. I replace the Delrin bearings every two years and the prop anode every year. Excellent next day service from Ambassador Marine for a properly drilled anode and bearings. Charles ------------- 'MERIDIAN LADY' 320 Nr 536 2010 Medway |
Posted By: kirkelund
Date Posted: 28 October 2014 at 19:39
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Hi everyone I think my rope cutter is also the Ambassador rope cutter. It is very simple and it seems to work fine. In fact, I have never noticed any problems. So it must have cut right through everything.....or I have just been lucky  Below is a picture of my rope cutter. Notice that a hole must be drilled through the anode on a Yanmar SD20 sail drive so that the inner knife is fixed while the other can swivel.  BTW, I spray the whole unit with Trilux antifouling (exept the anode, of course). The propeller is a Kiwi 3-blade feathering prop, which I am very happy with )Ole, ------------- Kirkelund "Amani" Lynetten, Copenhagen, Denmark Hanse 342 (grey hull, wheel steering, deep draft keel, Jefa rudder - RUD34) |
Posted By: CharlesP
Date Posted: 28 October 2014 at 20:02
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My boat has just been lifted. The fixed cutter is no longer fixed! The lug which goes through the anode seems to have sheered off, perhaps when it was munching through a thick rope which I mentioned in my previous post. Charles ------------- 'MERIDIAN LADY' 320 Nr 536 2010 Medway |