SHAFT SHARK line and rope cutter for your prop & shaft

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Nocanvas

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I am looking for some personal use stories on this device (Shaft Shark). One of the concerns I have is how effective is it and is the drag all that noticeable.
 
I have had a couple if different rope cutters. Had Spurs on one boat and a Shaft Shark on the current boat. They work great and I have not felt any drag from either type. Good insurance.
 
I have Sharks...never used them that I know of and they seem like a good product. Simpler and less parts than Spurs, which I've also had.
 
I have the Shark cutter. I have never noticed any additional drag from it. It is hard to say how often it has worked, once that I am quite sure of, maybe more often that I never noticed? I do know I have never had to diveonit to cut a line, or found a like wrapped on a haulout. They are pretty much maintenance free and very sharp, always remind divers that they are there so they can avoid getting cut.
 
I have the shaft sharks. The outside diameter is not much bigger than the prop hub, so its unlikely it has much of any drag. I know mine has "worked" at least once and it has never "not worked". (Never had a line wrap around the shaft tightly) They may or may not work all the time, its a last ditch defense.

Ken
 

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Shark or spur

I have had both spurs and shark on sail and power boats over many years. Both were effective, but had several occasions at haul out when I discovered all or part of a spur was gone, necessitating replacement. Never happened with the Shark, which, as noted, are much simpler. Never noticed any drag. However, when I did back up over my dockline (which was dumped in the water by an over eager deckhand), a diver was needed. And you certainly do have to caution any diver--they are sharp!! Wouldn't cruise without them here in the Northeast.
 
I think Practical Sailor Magazine did a review of line cutters. They decided that the bypass type, like Spurs, were a little more effective, but not much. The knife type are easier to install.

I had Spurs for 28 years and never had a problem with getting tangled in line. I did hit and cut a floating line on at least one occasion. Usually you just won’t know it has worked.
 
I have a PropProtector from the UK that works fine and costs less than half of what a Shark costs and much less than Spurs.
 
Has anyone tried these?? Sea Shield Marine SALCA – Sacrificial Anode Line Cutter Assembly (Amazon)

Hard to beat the price:thumb::thumb:
 
810105_4.jpg ASAP supplies $129.47USD
 
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Has anyone tried these?? Sea Shield Marine SALCA – Sacrificial Anode Line Cutter Assembly (Amazon)

Hard to beat the price:thumb::thumb:

Cost around forty bucks and looks kinda flimsy, plus you have to replace it frequently, I've had my ProProtector on for five years, works good and still looks new.Salca.jpg
 
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This Shaft Razor has 2 cutting surfaces and comes in 2 pieces so it can be installed without removing the prop

:socool:
 

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I am looking for some personal use stories on this device (Shaft Shark). One of the concerns I have is how effective is it and is the drag all that noticeable.

I had the shark on my main ship 390 and it saved my boat upon entering snake Creek at Islamorada when I ran over a line in shallow water and in the narrowest part of the channel with no room to spare. I felt it hit and then it spit it out in a split second. I’m sure it did not affect the performance of my boat and I will not sale in the keys without one. I now have a Hallberg Rassi sail boat and installed the shark on that boat as well.
 
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Has anyone tried these?? Sea Shield Marine SALCA – Sacrificial Anode Line Cutter Assembly (Amazon)

Hard to beat the price:thumb::thumb:

I had a set put on my ingle shaft a couple of months back, and I believe it worked the other day when there was a sudden rumbling down below while running at 15 MPH. I immediately stopped and checked the engine over and then slowly brought RPMs back up with no farther issues. My guess is the SALCA was doing its thing.
 
Cost around forty bucks and looks kinda flimsy, plus you have to replace it frequently, I've had my ProProtector on for five years, works good and still looks new.View attachment 87617


But its not much more that a zinc anyway and I think you could leave it installed when the zinc is exhausted and just place a new zinc firward of it. I cant imagine that exhausting the zinc would allow the cutter to come lose? But I have never seen one to examine the construction. The cutter is SS.
 
I installed the Prop Protector in January 2016. It traveled thousands of miles doing nothing, I was not expecting much from it. And we cruise in the Chesapeake, Albemarle , New England and the ICW , so we have experienced with dodging pots. Last summer we spent almost 8 weeks in the Erie Canal, Rideau Canal, St. Lawrence Seaway and lake Champlain. No pots! But upon return tot he sea we had a big thunk under the boat. No change in RPM, no vibration, no change in speed no sign of anything in our wake. When we were hauled out for bottom paint a month later we could see that the prop protector blade was bent in between two prop blades. Clearly it had done its job at some point . This spring it has worked once in the St Johns river and once in the Pasquatank. I'm now sold on them!
 

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But its not much more that a zinc anyway and I think you could leave it installed when the zinc is exhausted and just place a new zinc firward of it. I cant imagine that exhausting the zinc would allow the cutter to come lose? But I have never seen one to examine the construction. The cutter is SS.


I just called the manufacturer and they assured me the cutter would not fall off when the zinc depleted. And they also said the stock one is only 1.5" thick so it should fit in very tight places. They said it was NOT sharpened, but that you could sharpen it if you desired. I think I desire.


They also said that if 1.5" was too thick they could custom make one that would fit......I am sure there are limitations, however.


As soon as I divine the shaft size I will be ordering one.....!!
 
Line Cutters

I've used SALCA for about 5yrs and while I replace them yearly there are times where I did because they are also anodes.

As an anode they offer additional boat protection.

I have experience that they are also very effective line cutters.

Fitting between the strut and the prop I can't see any drag coefficient.

I just bought new 1's for this season but will check the existing set on the shaft (we were and will be in fresh water again this year so I'll probably save the new set.

Didn't understand the frequent replacement comment, BUT if someone has these and needs frequent replacement then they have a big issue with electrolysis.

I guess it boils down to paying $300 or more per shaft or $50.

Make your choice.
 
But its not much more that a zinc anyway and I think you could leave it installed when the zinc is exhausted and just place a new zinc firward of it. I cant imagine that exhausting the zinc would allow the cutter to come lose? But I have never seen one to examine the construction. The cutter is SS.

So you think the zinc will not deteriorate enough inside of a year or so to compromise the strength requiring replacement? The blade appears to be simply pinned through the zinc for support.
 
So you think the zinc will not deteriorate enough inside of a year or so to compromise the strength requiring replacement? The blade appears to be simply pinned through the zinc for support.

My prop shaft zinc never needs replacing....or at least doesn't now and it was put on two years ago. And I am also putting on a ShaftSaver that is actually designed to absorb shock when you hit something hard with the prop. But in the process it also electrically isolates the prop shaft from the engine effectively blocking any current path for corrosion. So it may last forever.

But even if I replaced it every year, it costs $38 and a plain zinc costs $24 so it costs me $14 more a year to have a line cutter. It would take me 20 years IF I CHANGED IT EVERY YEAR to spend as much more as a plain line cutter costs!!!!!..........

If you change the shaft zinc every year you have BIGGER PROBLEMS to worry about!!!!
 
My prop shaft zinc never needs replacing....or at least doesn't now and it was put on two years ago. And I am also putting on a ShaftSaver that is actually designed to absorb shock when you hit something hard with the prop. But in the process it also electrically isolates the prop shaft from the engine effectively blocking any current path for corrosion. So it may last forever.

But even if I replaced it every year, it costs $38 and a plain zinc costs $24 so it costs me $14 more a year to have a line cutter. It would take me 20 years IF I CHANGED IT EVERY YEAR to spend as much more as a plain line cutter costs!!!!!..........

If you change the shaft zinc every year you have BIGGER PROBLEMS to worry about!!!!
Everyone changes zincs every year where I am, my line cutter cost $129 when I bought it five years ago and I don't know if you've ever cruised the Maine coast but we have a lobster pot about every ten feet and mine has worked fine. But of course you should spend your money how you chose, I happen to be frugal so I look for what works and isn't overly expensive. By the way the current path from the engine isn't necessarily what eats zincs, may I suggest "Metal Corrosion in Boats" as a reference on the subject of stray current.
 
Slightly off topic, I would suggest that if any boat has sacrificial anodes which last "years", there is an issue with those anodes not providing protection.
 
Slightly off topic, I would suggest that if any boat has sacrificial anodes which last "years", there is an issue with those anodes not providing protection.

Good point, that's why I suggested a reference source, there's much more to preventing electrolysis than sticking zinc in the water.
 
Everyone changes zincs every year where I am, my line cutter cost $129 when I bought it five years ago and I don't know if you've ever cruised the Maine coast but we have a lobster pot about every ten feet and mine has worked fine. But of course you should spend your money how you chose, I happen to be frugal so I look for what works and isn't overly expensive. By the way the current path from the engine isn't necessarily what eats zincs, may I suggest "Metal Corrosion in Boats" as a reference on the subject of stray current.


Your condescending tone not withstanding, I will respond.

As you say, it depends on where you are. Where I am zincs dont need changing every year and I check them every 6 months. My diver will check mine this week. Yes, you may recommend the book, but I have read enough I dont need a new one. Yes, there can be corrosion without a direct path, but usually in a marina with bad wiring. And USUALLY not severe. I am NOT in a marina. If you want to justify your expenses by your environment, thats fine, you should. My environment is apparently much cleaner electrically.

Again, if you change your zincs yearly, you have a problem that you should be fixing. Maybe on your boat, maybe in your marina. May I suggest an isolation transformer and/or possibly solar panels instead of shore connection.
 
Your condescending tone not withstanding, I will respond.

As you say, it depends on where you are. Where I am zincs dont need changing every year and I check them every 6 months. My diver will check mine this week. Yes, you may recommend the book, but I have read enough I dont need a new one. Yes, there can be corrosion without a direct path, but usually in a marina with bad wiring. And USUALLY not severe. I am NOT in a marina. If you want to justify your expenses by your environment, thats fine, you should. My environment is apparently much cleaner electrically.

Again, if you change your zincs yearly, you have a problem that you should be fixing. Maybe on your boat, maybe in your marina. May I suggest an isolation transformer and/or possibly solar panels instead of shore connection.

My boats on a mooring in a harbor with no marina or dockside electric, every boat here and to my knowledge the Maine coast changes zincs on at least an annual basis. As alluded to there's more to this issue than simply a zinc, I'm happy for you that this isn't an issue but I must say I've never heard of someone that has "read enough". As I appear to have annoyed you with my comments, for which I apologize, I wish you the best of luck and happy boating.
 
I've never heard of someone that has "read enough". As I appear to have annoyed you with my comments, for which I apologize, I wish you the best of luck and happy boating.

When it comes to corrosion, its not hard to get to "read enough" I find no two books that agree on the subject. Been reading for over 78 years.

You did not annoy me with your comments, only with the tone of condescension. All comments are valuable in a discussion, but attitude is not. And it continues with the comment about "read enough". Thus your apology is insincere. You are still condescending, apology aside.
 
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