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Anonymous
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I shan't be able to go to Seaworks in June. What did you learn after talking to the commercial vessel owners and operators?
Rope-Cutters on Prop-Shaft
- Thread starter Babylon
- Start date
vyv_cox
Well-Known Member
When I discussed this issue with Ambassador after my first failure they told me that the fixed part was designed to fracture before the bolts either fractured or stripped out. I think this may well be the case but it assumes that the bolts are attached by a number of turns into a good solid piece of metal. In my case, in two different P-brackets, they have only been in a couple of turns because the metal around the cutless bearing on modern brackets is intended only to hold the bearing, and is only about 3-4 mm thick.
The photo shows the old P-bracket after the bolts stripped out.
There are no threads left inside the bracket. I drilled and tapped them before fitting the cutless bearing so I'm certain the threads were good. It does look as though there might be some corrosion around the fixing holes, which may well have contributed. As I said earlier, if I was doing it again I would drill and tap right through the brass of the cutless bearing as well and use longer bolts. However, I have virtually decided to go with a disc type, my decision helped by the relative absence of lobster pots and such like in the eastern Med
The photo shows the old P-bracket after the bolts stripped out.
There are no threads left inside the bracket. I drilled and tapped them before fitting the cutless bearing so I'm certain the threads were good. It does look as though there might be some corrosion around the fixing holes, which may well have contributed. As I said earlier, if I was doing it again I would drill and tap right through the brass of the cutless bearing as well and use longer bolts. However, I have virtually decided to go with a disc type, my decision helped by the relative absence of lobster pots and such like in the eastern Med
Tranona
Well-Known Member
Interesting comment about the Eastern Med. The problem I have hit is plastic bags, but there has also been a significant increase in the amount of fishing in the shallow waters such as just north of Ignoumenitsa and around Preveza. The other problems in the area in general are lazy lines, mooring warps (other peoples of course!) in congested harbours and sheets over the side!
Refueler
Well-Known Member
The only way I would fit a new block would be to have spigots locate in old holes to provide 'key' and then clamp in place. I would be against drilling further holes into the stern tube casting. It's a bronze casting and I don't think they take kindly to too much force too many times. i accept it would probably be fine to remount a new block with new tapped holes. But I know I'm going to be in / out of my canal with reduced water again. rather expensive to keep buying blocks !!
I did consider fabricating my own design block incorporating the spigot idea and is still a possibility. When local stainless fabricator saw the whole assembly before I fitted he scratched his chin ... offered to make another ... gave me price. But he also pointed out a few areas of the design he felt were up for improvement. One funnily enough was method of block attachment ! But it works and that's all that's important !!
I did consider fabricating my own design block incorporating the spigot idea and is still a possibility. When local stainless fabricator saw the whole assembly before I fitted he scratched his chin ... offered to make another ... gave me price. But he also pointed out a few areas of the design he felt were up for improvement. One funnily enough was method of block attachment ! But it works and that's all that's important !!
vyv_cox
Well-Known Member
The number of floating plastic bags off Italy was astounding but our experience off Greece has been much better. Agree about the fishing though, now quite large numbers of floats in the shallows between Preveza and Levkas.
One of my Stripper failures was caused by our own stern warp, just an accident that the end of it fell overboard as we were going stern-to on Levkas town quay. The rope wrapped around the prop and stopped the engine dead, the fixed part of the stripper fell off but the rope was not cut. I couldn't get out of reverse gear so couldn't unwind the warp but managed to only cut about 30 cm off the end.
An Italian boat was on our starboard side, he reacted very quickly and took another warp from us, so we were able to hold alongside him until I got ashore and fastened to the bollards. The German on our port side said helpfully ' You have a warp around your propeller!'
One of my Stripper failures was caused by our own stern warp, just an accident that the end of it fell overboard as we were going stern-to on Levkas town quay. The rope wrapped around the prop and stopped the engine dead, the fixed part of the stripper fell off but the rope was not cut. I couldn't get out of reverse gear so couldn't unwind the warp but managed to only cut about 30 cm off the end.
An Italian boat was on our starboard side, he reacted very quickly and took another warp from us, so we were able to hold alongside him until I got ashore and fastened to the bollards. The German on our port side said helpfully ' You have a warp around your propeller!'
Tranona
Well-Known Member
I have picked up plastic twice. The first time was in the middle of the Corfu channel. Stopped the engine but a bit of forward reverse cleared enough to get 3-4 knots. Gradually got a bit faster as bits fell off, but still enough wrapped round to make it worth sending down the diver in Gouvia. Last one was a blue shopping bag going into Platerias. Came off fairly easily.
I have a saildrive which in some ways is better as it is closer to the keel and further forward, but my concern is plastic wrapping round the leg and blocking the water inlet. Stripper going on this year!
I have a saildrive which in some ways is better as it is closer to the keel and further forward, but my concern is plastic wrapping round the leg and blocking the water inlet. Stripper going on this year!
A
Anonymous
Guest
[ QUOTE ]
Stripper going on this year!
[/ QUOTE ]So my personal experience, and that of my cruising friends are "old wives' tales"? What personal experience of cutters do you actually have?
Stripper going on this year!
[/ QUOTE ]So my personal experience, and that of my cruising friends are "old wives' tales"? What personal experience of cutters do you actually have?
A
Anonymous
Guest
[ QUOTE ]
The German on our port side said helpfully ' You have a warp around your propeller!'
[/ QUOTE ]Been there. What is it about Germans?
The German on our port side said helpfully ' You have a warp around your propeller!'
[/ QUOTE ]Been there. What is it about Germans?
Tranona
Well-Known Member
Only 25 years I am afraid. Since they first came on the market. Just so happens that my Bavaria did not have one and I was not able to fit it when I took it over last year.
OK?
OK?
Neil_Y
Well-Known Member
So far over 4 years of supplying quicKutter and only two have needed any spares out of several hundred fitted, mostly to commercial vessels. Ferries, Pilot boats, Naval survey, RNLI, fishing boats. This is proof of robustness, as far as effectiveness recent articles in the fishing press interviewing commercial fishing boat operators have confirmed they work.
Unlike other systems the shaver cutter relies on debris being wound tight to cut it. If it isn't winding it is unlikely to get caught and do damage.
The recent test fixed one end of the debris to the bearing end, this meant that as it was drawn over teh disc or scissor it was fixed and not rotating with the shaft. In practice if debris is caught by the prop it will be rotating with the shaft, if this had been tested I would have expected completely different results and we would have taken part.
Unlike other systems the shaver cutter relies on debris being wound tight to cut it. If it isn't winding it is unlikely to get caught and do damage.
The recent test fixed one end of the debris to the bearing end, this meant that as it was drawn over teh disc or scissor it was fixed and not rotating with the shaft. In practice if debris is caught by the prop it will be rotating with the shaft, if this had been tested I would have expected completely different results and we would have taken part.
Babylon
Well-Known Member
I wanted to fit the QuicKutter but the yard shied away
Hi Neil
In the end I had an Ambassador cutter fitted by the yard - not because they are 'better' than the QuicKutter, but because both Solent yards I had quoting for the work (including new prop shaft etc) shied away from a product they had no real experience of and recommended I go with the Ambassador unit which is manufactured locally. I also think there was the minor issue of having a local engineering shop mill up the sleeve to customise it to the exact dimensions necessary - an additional process that probably had them groaning a bit - so they chose to stick with what (and who!) they knew.
You mentioned on the phone to me that you were due to visit the South Coast yards to present and promote your product - hope you had some success, as without some proper promotion to familiarise them they'd most probably continue to stick with what they know.
Babs
Hi Neil
In the end I had an Ambassador cutter fitted by the yard - not because they are 'better' than the QuicKutter, but because both Solent yards I had quoting for the work (including new prop shaft etc) shied away from a product they had no real experience of and recommended I go with the Ambassador unit which is manufactured locally. I also think there was the minor issue of having a local engineering shop mill up the sleeve to customise it to the exact dimensions necessary - an additional process that probably had them groaning a bit - so they chose to stick with what (and who!) they knew.
You mentioned on the phone to me that you were due to visit the South Coast yards to present and promote your product - hope you had some success, as without some proper promotion to familiarise them they'd most probably continue to stick with what they know.
Babs
Neil_Y
Well-Known Member
You're right, it is the devil you know problem for many yards.
The local demo's have been helping, but I often end up spending more time with the yards that are running contract work on commercial or Naval vessels. That way we sell more bearings for rudders and stern tubes as well as cutters.
If it was a simple bolt on fitting life would be much simpler!
I hope you never need the cutter or it works for what ever you catch. Having been there with a net around the prop it can be a terrifying experience. Mine worst was in a 10m+ swell off the Spanish west coast with the wind dropping in November.
The local demo's have been helping, but I often end up spending more time with the yards that are running contract work on commercial or Naval vessels. That way we sell more bearings for rudders and stern tubes as well as cutters.
If it was a simple bolt on fitting life would be much simpler!
I hope you never need the cutter or it works for what ever you catch. Having been there with a net around the prop it can be a terrifying experience. Mine worst was in a 10m+ swell off the Spanish west coast with the wind dropping in November.