Replies Regarding These Shaft Cutters

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We put it on the end of a telescoping boat hook then get >12’. As we cut use another boat hook to pull cut segments away and work our way down. It has three cutting surfaces so you start from outside in when you can’t wiggle it into a lump of nylon line. Nylon usually floats so that’s helpful. Hardest part is stabilization of the dinghy far enough away so you can see what you’re doing. We’ve used several fenders as the meat in a sandwich to achieve that distance and a firm platform. Downeast the water is brutally cold. Without a dry suit you’re not doing this in the water.
 
I've thought a lot about installing cutters on my shaft. So far, the decision remains "no". This is probably because I've not had many "tangle" situations...and definitely none that I couldn't solve myself with a quick swim and a knife. I am also put off by stories I've read of divers getting severely injured on the cutters...when human attention was required because the tangle was too much for the cutters.


Perhaps if I traveled in shark-infested waters, I would find myself thinking differently...
 
After a bad entanglement in Maine, I decided that sharp cutters and more throttle was the solution to un-managed lobstering by our neighbors. I installed shark cutters because they were a simple retrofit as opposed to the major project that spurs would have been.


Someone mentioned clearance, and that's very important. You need enough space forward of the prop hub to fit the shark, while leaving enough space for water flow through any cutlass bearing.


And the things are super sharp, so be really careful installing them, as well as when doing any work in their vicinity.


Did they work? I have no idea. It's like engine additives, and brands of oil. You can't prove a negative. I never knowingly ran over, cut, and continued free of any rope, so who knows. But I sure felt better about things.


My last two boats have come with spurs, and as far as I know, they have never been called into service.


If you do get entangled, just know that you will be fortunate if you can dive down holding your breath and get cut free. After my boat was hauled and I was sitting comfortably in front of the mess, it took me a good hour to cut it all free. It's no longer line at that point, but rather a molded lump of stranded plastic that has been cast around your shaft.
 
Alaskan Sea-Duction said:
Has anyone tried these shaft cutters? Good bad and ugly?

https://ab-marine.com/shaft-shark/
Click to expand...

We've had the Sharks for about 10 years. They work fine as "possibly" evidenced by never finding a crab pot line when doing the annual haul out. Once we caught a part of a derelict drift net, after spitting out cut up rope and line for about 2 minutes the job was done.

They are sharp, divers be warned.
 
I have had Shaft Sharks on 3 boats now without a problem. Before that I had at least one pot line caught on my props per year. For 10 years now, nothing. I no longer keep my scuba gear onboard.
 
I recently switched from Spurs to Shark Shaft after several design and installation problems with the spurs. The spurs requires attachment to the vessel and that lead to $1K repair three years ago. Next the spurs came loose on the shaft and wore a grove so I had to replace the shaft. To be fair, my diver and I missed the zinc required on the spurs -when I hired a new diver. The Shark shaft is all stainless just like your shaft. I have never knowingly hit a crap pot line, but the Spurs might have done the job? James Knight at Yacht tech suggested I buy a Shark Shaft at defender on sale and they installed in less than 20 mins-sweet and simple. ! I am hoping it's a better mousetrap, just like the Smart Plug and gear driven REVERSO-NEVER LOOK BACK.
 
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Alaskan Sea-Duction said:
Has anyone tried these shaft cutters? Good bad and ugly?

https://ab-marine.com/shaft-shark/
Click to expand...

Yes I have them.
Once we felt a “thud” and momentary hesitation while cruising in Bahamas.
Had some minor vibration, dove down when we reached our destination and found a bunch of line trailing and wrapped on the prop.
I suspect the thud was the crab pot hitting the hull and the hesitation was the power reduction as the line was being cut.

Bottom line is peace of mind, I suspect that while a dive was still needed to remove all the line, the cutters kept us from having a totally fouled and locked shaft.

Would recommend.
 
I had Shark Shafts on my Sportfish (30 Rampage) for 10 years and had no issues with them at all, and they cut off (Crabbers/Lobster guys stop reading here!!) MANY MANY pots over the years! The bay I boated in on the way back to port was loaded with them, in the channels and out.... no way of avoiding at night.



I don't hvae experience with the spur type, but I made my decision based on a boat show recommendation from a guy selling both: "The spurs are ok, but DANGEROUS! If you ever need to work on things, especially underwater you can easily loose a finger or two from the shaft turning a bit." The shaft sharks are also sharp, but much harder to be injured from....
 
Shark cutters

Have these on my 43 ALBIN. Love em. Mounted between strut & prop- tight to prop forward face to leave water flow thru the cutlass brg. Have seen many 'Spurs' with missing parts at haul out.
 
I installed a pair on my 36 Albin Trawler last season. Easy to install, not so cheap, sharp as hell. Haven't been in a situation where I needed them yet, but it's bound to happen at some time.
 
Highly reccomend

They seemed overly expensive when I bought them. Wrong! Very high quality product , extremely (dangerously) sharp, after 10 years in Penobscot Bay.

You should know that when you think you’ve hit a line, or hear the buoy thump the hull hit the throttle.
 
Shaft cutters

Everyone has a favorite and will be on the side (need, don't need) based on their pocketbook and common sense.

IF I needed to spend $300/shaft it might make me decide I didn't need them, that is of course until I needed them.

Yrs ago I came across something called SALCA. Sacrificial Anode Line Cutter Assembly. These sever 2 purposes, which anything you bring on a boat is supposed to serve, plus they are economical.

Look here (https://tinyurl.com/fowdp5gb). You can get these in zinc or aluminum and I've had them last 2 yrs before replacement.

At this price, maybe those who thought they didn't need them now have a need for them. BTW, they have worked for me.
 
Another alternative

I installed a serrated cutter in 2016 on our 37 NT before heading out on the Downeast Circle. After a season cruising in Northern Maine and one incident where the cutter did work but only after 25 of line was wrapped around the shaft, I decided to install a prop cage. Many lobster boats use them. A local welding company designed and built the cage for $1200 (recommended by a TF member). Install was about a day DIY. Best decision we ever made! Yes, there is a slight drag snd minor increase in fuel consumption but peace of mind is worth it.

For those not familiar with this area, lobster floats are so thick in places that finding a path through them is almost impossible even with good visibility ... forget autopilot! Throw in low sun, any chop or fog and it is inevitable you will catch a line.

We subsequently spent three seasons cruising in Maine with no concerns.
 
Nepidae said:
Everyone has a favorite and will be on the side (need, don't need) based on their pocketbook and common sense.

IF I needed to spend $300/shaft it might make me decide I didn't need them, that is of course until I needed them.

Yrs ago I came across something called SALCA. Sacrificial Anode Line Cutter Assembly. These sever 2 purposes, which anything you bring on a boat is supposed to serve, plus they are economical.

Look here (https://tinyurl.com/fowdp5gb). You can get these in zinc or aluminum and I've had them last 2 yrs before replacement.

At this price, maybe those who thought they didn't need them now have a need for them. BTW, they have worked for me.
Click to expand...

Charles, maybe you did not tangle with anything during the period you had the SALCA/zinc cutters, but as I earlier said in this thread, I had two successive SALCAs on my shaft (lift kept boat; so they were not immersed more than a few hours), and they "left the building" very quickly, once after one served its purpose and cut some line, and the second time for unknown reason. I don't think either lasted six months. I now have a disc cutter in place.
 
Rich,

If you had a quick diminishing of the anode then you may have an issue with a ground. Even if kept out of the water. The SALCA should not wear any faster than your other anodes on your boat.

I've been using the SALCA for about 8yrs now with no rapid loss of the anode. In '16 with a big upgrade project being done to the boat in preparation for the Loop, which we are still on, I had a galvanic isolator added along with an ELCI.

Even with minimal wasting, I usually change anodes yrly, including the SALCA.

I've also used the aluminum version but to this point, we've been mostly in fresh or brackish water.

We'll be getting to Mobile and the NW corner of FL this yr so we'll see how the anodes hold up. Have a fresh set on the boat ready to go next yr.

For me, $300+ per shaft is a bit too much for cutters. I know the SALCA work as I've had some leftover line in the struts once or twice so I'll stick with them.

Take care & stay safe & healthy.
 
Nepidae said:
Rich,

If you had a quick diminishing of the anode then you may have an issue with a ground. Even if kept out of the water. The SALCA should not wear any faster than your other anodes on your boat.

I've been using the SALCA for about 8yrs now with no rapid loss of the anode. In '16 with a big upgrade project being done to the boat in preparation for the Loop, which we are still on, I had a galvanic isolator added along with an ELCI.

Even with minimal wasting, I usually change anodes yrly, including the SALCA.

I've also used the aluminum version but to this point, we've been mostly in fresh or brackish water.

We'll be getting to Mobile and the NW corner of FL this yr so we'll see how the anodes hold up. Have a fresh set on the boat ready to go next yr.

For me, $300+ per shaft is a bit too much for cutters. I know the SALCA work as I've had some leftover line in the struts once or twice so I'll stick with them.

Take care & stay safe & healthy.
Click to expand...

I did not attribute the losses of my SALCAs to zinc corrosion. I believe the first loss was due to the overpowering strength of the mass of plastic webbing I hit. The second loss was a complete mystery as to cause. The SS disk I now use is doing well. All anodes in the engine and on the bow thruster and trim tabs showed no evidence of accelerated loss during in-water storage. So I do not think there is any electrical issue. Except for the year plus of in-water storage after Hurricane Michael I do not use a shaft or tab zincs because of the normal out of water storage. I still have tab zincs on from that in-water time - will remove them this summer. Boat is bonded.
 
I have the shaft sharks on my boat.

Can't say for sure if they work, I only know that I've run over some serious kelp and not had a problem, and I used to have kelp dragging off my rudders occasionally.

They are still sharp after several years and a couple haulouts.
 
My hold up is the cost. Over $800 per shaft. But then again the cost of the damage cause by a crab pot...
 
Alaskan Sea-Duction said:
My hold up is the cost. Over $800 per shaft. But then again the cost of the damage cause by a crab pot...
Click to expand...


HUH?? I bought mine for $200 if I recall, install takes 5 minutes with an Allen key
 
All anecdotal. I installed Shaft Sharks only because I couldn't fit the cutters on my exposed shaft. The cutters seemed like a theoretically better idea. But, not enough room on a Grand Banks 36 shaft for a cutter assembly. My friend at the boatyard advised that the commercial guys actually prefer the shaft shark to the cutters, so I went with that. No problems, though this ain't Maine. But we do have crab pots, which I think I avoid in my daily travels, but they do take a bit of attention, so I may have missed a few. Anyway, anecdotally the shaft sharks get my support.
 
Shat Cutter

I installed one of these on my Mainship Pilot 30 II and did not have good luck with it. The first trap line I picked up wound so tight around my shaft it stalled the engine and broke one of the rear cast aluminum motor mounts. I went to a spur style cutter and so far it has cut two lines flawlessly. The picture that "murofrelwart" posted shows the hub of the cutter very close to the cutlass bearing. Any style cutter that is installed wants to be a minimum of 1/4" to 3/8" from the cutlass bearing housing (depending on whether it is a strut mounted bearing or a sternpost mounted bearing) to allow water to flow thru the bearing without restriction.
 
CharliePatten said:
..... The picture that "murofrelwart" posted shows the hub of the cutter very close to the cutlass bearing. Any style cutter that is installed wants to be a minimum of 1/4" to 3/8" from the cutlass bearing housing (depending on whether it is a strut mounted bearing or a sternpost mounted bearing) to allow water to flow thru the bearing without restriction.
Click to expand...




I agree, here is a better picture of my install. I didn't measure the gap, but it hopefully allows for adequate flow through the cutlass bearing.
 

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Our boat, bought in Maine, came with shaft sharks. (Maybe a lesson there?) during a number of subsequent cruises in Maine have twice found very short remnants of line hanging off a prop. No wraps, no pausing, no heavy cutting needed. We try very hard to miss lobster gear but apparently these work when the unseen gets in there.

Ken
 
Are the "lobster" pots using floating line. some of the stories here suggest this. Some of you make it sound normal and expected to come across a line to tangle into.

BTW, is there any reason the prop cannot have a knife edge near the hub?
 
Soo-Valley said:
Are the "lobster" pots using floating line. some of the stories here suggest this. Some of you make it sound normal and expected to come across a line to tangle into.

BTW, is there any reason the prop cannot have a knife edge near the hub?
Click to expand...

One example, this pic from Vinalhaven Maine
 

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If somewhere is that dense with pots, unless I'm in dire need of fuel, I'm just not going there. Not worth the risk.
 
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