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I have picked up a vibration in the driveline. It is pretty much at all RPMs.

This is detailed and I'm sorry about that but I'm trying to head off a bunch of false diagnoses.

  • New damper plate
  • New transmission
  • New shaft log hose
  • New shaft coupling
  • Freshly packed gland seal
  • ZERO slop or play in any of these components

I checked but did NOT replace the cutlass bearing. I also have a very old Martec folding prop. I have visually checked the prop and shaft with a camera on a pole but I have not yet entered the water because I'm in a rather industrial harbor and I dislike cancer.

Can a sloppy Martec transfer vibration even once the blades are flipped out and loaded? The vibration definitely feels under the helm seat, not in the engine space. None of the shaft components visually vibrate. Gland seal drips at appropriate rate and not at all when the shaft is at rest.

Thoughts?

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I had my Martec rebuilt and resized by them and couldn't be happier with it - it powers like a fixed 3 blade forward and reverse.

Big clunk when it opens but no further vibration.

From your list I'd say 3 possibilities - the prop is sloppy, the cutless wasn't as good as you thought or the shaft alignment has gone out of line.

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3 minutes ago, SloopJonB said:

I had my Martec rebuilt and resized by them and couldn't be happier with it - it powers like a fixed 3 blade forward and reverse.

Big clunk when it opens but no further vibration.

From your list I'd say 3 possibilities - the prop is sloppy, the cutless wasn't as good as you thought or the shaft alignment has gone out of line.

Or there's a loose zinc.

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23 minutes ago, ChrisJD said:

Could you have picked up a bit of line that wrapped itself around the prop?

I put my Faux Pro on a pole and looked at the rudder and prop.  No debris. That's not a physical hand on inspection though.  

Diver coming tomorrow or Monday. 

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1) My first thought was a rope/weed on the prop shaft. It's almost the default cause.

2) But a loose zinc can certainly cause vibration. Even a really irregular shaped one will upset the balance of the driveline

3) Prop:  Have your diver grab the blades of the prop and feel/twist the blades and check for wear in the pivot pin. Especially differences between the 2 blades. 

4) Shaft: If you hit something you could have bent the shaft slightly. If there is any significant amount of the shaft inside the boat (more than say 6" exposed between gearbox and stuffing box, you could take a marking pen/pencil and clamp it to something solid nearby, just barely touching the shaft. Then rotate it in neutral by hand and see if you make more of a mark on one side.

5) inspect all 4 engine mounts. Push on the engine hard, side to side, front to back. Rubber mounts can fail and still look ok. A failed mount might mean lots of misalignment.

That's all I got for now.

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@Zonker great stuff,  thanks very much. 

I have very little exposed shaft in the boat but I'll check.  My engine was designed with a tripod mount,  so only 3!  I did just check them because of the new transmission installation but I'll check them again tomorrow. 

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Plus one for zinc, even a tiny loose it will sound like alot more than it is.  Also anything in the wheel.  Hard to see without a diver.

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5 hours ago, longy said:

When did this vibe start? Before or after all the work?

After all the work,  but months after,  not days. 

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The Martec is a low-drag prop designed for racing. It isn't a particularly good choice for a cruising boat that needs to motor efficiently. A whole bunch of potential causes of your problem have been identified here. More likely than not, it is one or more of those issues.

If you suspect a shaft zinc is the issue, just have the diver remove it. The more likely problem is wear in the prop pivot pins. You also have to remember if you are motoring in substantial seas, the mass of the engine moving on its mounts can cause binding in the cutless bearing and/or stern bearing, depending on your installation.

I had a three-bladed Maxprop with externally adjustable pitch on my last boat. I could fine-tune the pitch for the loading by simply going over the side and turning the adjusting ring. For some reason, they don't make that version of the Maxprop any more.

Every folding/feathering prop I have seen is subject to internal wear on the gears or wear in the pivots, depending on the design. Once it starts, it gets worse very quickly.

I was inspecting my old boat the other day for the new owner, and found substantial play in both the prop blades and the cutless bearing. These get neglected by most folks.

In that particular case, that prop has several thousand hours of motoring on it, and the cutless bearing may be the one I put in during a re-fit in NZ in 2000.

Cruising sailboats very much depend on a reliable, efficient motoring system.

Ajax has done the right thing by his boat, but there may still be some loose ends to sort out. Those often don't appear until you start using the engine and drive train harder than normal.

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If you don't find anything in the water, I would put a wrench on the engine mounts.  I had two loosen up before.  They should be torqued, was in a hurry finished the alignment and thought I had everything right enough.  After a month or so and getting in some sloppy weather saw evidence of movement in one of the slotted mounts.  Not saying this is it but it's not unheard of for things to work loose after some run hours and abuse.  Definitely would start with a diver though

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Well it's Sunday and no call from the diver (understandable).  After a bunch of cleaning, tidying and reading up on the issue I'd finally had enough waiting and went into the water. Glad I brought the wetsuit, it wasn't ice cold but it's bracing. 72F.

  • Grabbed and shook the rudder. Nothing. It's a heavy beast and I've got little leverage down there.
  • Second, I grabbed the shaft and tried to move it around in the cutlass bearing. Nothing, solid as ever.
  • Next, I performed the @Zonker Martec blade twist test- Ah ha!  Wow, that's bad. Both blades clunk but one was noticeably worse.
  • There is almost no hard growth on any of the running gear. The zincs are wearing but not badly deformed. I popped a couple barnacles off of the prop.
  • The last thing I did after getting back into the boat and giving myself a decontamination shower in the cockpit was to remove the dog house and check the engine mounts. They are secure and perfectly fine.

The engine is a 3 cylinder so it's not especially smooth like a 4 cylinder or an Atomic 4. I made sure to set the throttle at the point where the engine is least smooth to observe the mounts, belts, etc. Nada. All good. I then took a large screwdriver and pried on the engine a bit and couldn't find any separation of the rubber or anything like that with the mounts.

My money is on the prop. It was an emergency consignment shop purchase when I bought the boat 4-5 years ago. I haven't paid it a second thought since I slapped it on there, unlike practically everything else. It's never been refurbished that I'm aware of.

The Plan:  My wife is driving up tomorrow anyway, to start her vacation with me. I have a spare, fixed blade Michigan Sailor propeller. She found it and is bringing it to me. I will contact people tomorrow morning to determine if the best plan is to have the diver do it, or pick one of the 4 yards to hang it in the slings and send one of their monkeys under the boat to swap out the props.

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1 hour ago, Ajax said:

Well it's Sunday and no call from the diver (understandable).  After a bunch of cleaning, tidying and reading up on the issue I'd finally had enough waiting and went into the water. Glad I brought the wetsuit, it wasn't ice cold but it's bracing. 72F.

  • Grabbed and shook the rudder. Nothing. It's a heavy beast and I've got little leverage down there.
  • Second, I grabbed the shaft and tried to move it around in the cutlass bearing. Nothing, solid as ever.
  • Next, I performed the @Zonker Martec blade twist test- Ah ha!  Wow, that's bad. Both blades clunk but one was noticeably worse.
  • There is almost no hard growth on any of the running gear. The zincs are wearing but not badly deformed. I popped a couple barnacles off of the prop.
  • The last thing I did after getting back into the boat and giving myself a decontamination shower in the cockpit was to remove the dog house and check the engine mounts. They are secure and perfectly fine.

The engine is a 3 cylinder so it's not especially smooth like a 4 cylinder or an Atomic 4. I made sure to set the throttle at the point where the engine is least smooth to observe the mounts, belts, etc. Nada. All good. I then took a large screwdriver and pried on the engine a bit and couldn't find any separation of the rubber or anything like that with the mounts.

My money is on the prop. It was an emergency consignment shop purchase when I bought the boat 4-5 years ago. I haven't paid it a second thought since I slapped it on there, unlike practically everything else. It's never been refurbished that I'm aware of.

The Plan:  My wife is driving up tomorrow anyway, to start her vacation with me. I have a spare, fixed blade Michigan Sailor propeller. She found it and is bringing it to me. I will contact people tomorrow morning to determine if the best plan is to have the diver do it, or pick one of the 4 yards to hang it in the slings and send one of their monkeys under the boat to swap out the props.

It will be easier to do with the boat in the lift slings. Props don’t often pop right off, and you need quite a  bit of torque on the nuts. Don’t forget the cotter pin in the nut.

Motoring with a Martec is seriously inefficient at the best of times.

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11 minutes ago, accnick said:

It will be easier to do with the boat in the lift slings. Props don’t often pop right off, and you need quite a  bit of torque on the nuts. Don’t forget the cotter pin in the nut.

Motoring with a Martec is seriously inefficient at the best of times.

I'm excited about actually having reverse thrust. 

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42 minutes ago, Ajax said:

I'm excited about actually having reverse thrust. 

Yeah, Good stuff. I pop mine into reverse and with a quick burst of throttle, and the boat comes to a screeching halt.

it will be a miracle compared to your Martec.

We put the 3-blade Maxprop on because we knew we would be motoring a lot in parts of the world, like SE Asia. Turned out we underestimated how much we would actually be motoring.

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Get the Martec rebuilt by them - in Arizona now and do it as a retirement sideline. Barring problems it should cost about 10% or 15% of a new prop.

As I stated upthread, I couldn't be happier with mine. People trash talk them but mine works like a fixed 3 blade forward and backward.

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Ajax, We have a Flexofold 2 blade, so not the same but definitely encountered some drivetrain vibrations that were difficult to trace. Ended up replacing the blades on the prop because the gears were worn and didn't have reverse. After installing the new blades the vibration was gone. Not something you can easily verify yourself, especially while in the water other than changing it out, but hey, if everything else checks out it does have moving parts.

 

Pat

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Fixed props are pretty cheep, sure you can find a local shop to set you up with new or used and send out your other one for a repair.  In the end it's not a bad idea to have that fixed blade one kicking around the bilge for just this.  You wack something or have a issue and you just need to swap props and off you go.  We had a new shaft and fixed prop made by Kruger in Seattle I thought bit would be way more than it ended up being.

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Just now, SASSAFRASS said:

Fixed props are pretty cheep, sure you can find a local shop to set you up with new or used and send out your other one for a repair.  In the end it's not a bad idea to have that fixed blade one kicking around the bilge for just this.  You wack something or have a issue and you just need to swap props and off you go.  We had a new shaft and fixed prop made by Kruger in Seattle I thought bit would be way more than it ended up being.

I sold our old fixed blade 17X9 for $100, after I docked the shaft to fit the Max Prop it didn't fit any more.

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2 minutes ago, Ishmael said:

I sold our old fixed blade 17X9 for $100, after I docked the shaft to fit the Max Prop it didn't fit any more.

That's wierd they didn't do anything to ours when we went to four blade max prop.  I think I need to move it in the coupling a little but that's it.

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14 hours ago, TryGuy said:

Ajax, We have a Flexofold 2 blade, so not the same but definitely encountered some drivetrain vibrations that were difficult to trace. Ended up replacing the blades on the prop because the gears were worn and didn't have reverse. After installing the new blades the vibration was gone. Not something you can easily verify yourself, especially while in the water other than changing it out, but hey, if everything else checks out it does have moving parts.

 

Pat

All of my fingers and toes are crossed. It's not just that the prop would be a simple fix, it's that after a detailed inspection, I simply cannot find anything else wrong.

The vibration was high frequency, more of a thrumming, not a low frequency "knock fillings out of your teeth"  It also would manifest itself after the swell would pass under the boat and the prop/driveline would get loaded up again. Kind of a BRRRRRrrrrrrr......(silence)....BRRRRRRrrrrr....(silence).

It was *way* too rolly at the time to stuff myself into the lazarette for a detailed look. I was able to remove the pop-out panel in the quarterberth for a simple observation with the engine running and I saw nothing amiss but I could certainly hear it. I had to head back up-deck to avoid puking from the rolling.

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20 hours ago, SloopJonB said:

Get the Martec rebuilt by them - in Arizona now and do it as a retirement sideline. Barring problems it should cost about 10% or 15% of a new prop.

As I stated upthread, I couldn't be happier with mine. People trash talk them but mine works like a fixed 3 blade forward and backward.

Yep, did the same for mine. Works great. No complaints other than the "ca-chunk" going into gear.

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That sounds pretty much like what ours was doing, with the added feature of no reverse, something Flexofolds usually do pretty well. Good luck! 

 

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On 7/11/2021 at 1:33 PM, Ajax said:

Well it's Sunday and no call from the diver (understandable).  After a bunch of cleaning, tidying and reading up on the issue I'd finally had enough waiting and went into the water. Glad I brought the wetsuit, it wasn't ice cold but it's bracing. 72F.

  • Grabbed and shook the rudder. Nothing. It's a heavy beast and I've got little leverage down there.
  • Second, I grabbed the shaft and tried to move it around in the cutlass bearing. Nothing, solid as ever.
  • Next, I performed the @Zonker Martec blade twist test- Ah ha!  Wow, that's bad. Both blades clunk but one was noticeably worse.
  • There is almost no hard growth on any of the running gear. The zincs are wearing but not badly deformed. I popped a couple barnacles off of the prop.
  • The last thing I did after getting back into the boat and giving myself a decontamination shower in the cockpit was to remove the dog house and check the engine mounts. They are secure and perfectly fine.

The engine is a 3 cylinder so it's not especially smooth like a 4 cylinder or an Atomic 4. I made sure to set the throttle at the point where the engine is least smooth to observe the mounts, belts, etc. Nada. All good. I then took a large screwdriver and pried on the engine a bit and couldn't find any separation of the rubber or anything like that with the mounts.

My money is on the prop. It was an emergency consignment shop purchase when I bought the boat 4-5 years ago. I haven't paid it a second thought since I slapped it on there, unlike practically everything else. It's never been refurbished that I'm aware of.

The Plan:  My wife is driving up tomorrow anyway, to start her vacation with me. I have a spare, fixed blade Michigan Sailor propeller. She found it and is bringing it to me. I will contact people tomorrow morning to determine if the best plan is to have the diver do it, or pick one of the 4 yards to hang it in the slings and send one of their monkeys under the boat to swap out the props.

The diver route will save you a few bucks but I would go with a quick haul simply because you will be able to physically examine and confirm the work is done right. It’s not going to be a huge difference in price but the peace of mind is good to have.

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I'm operating on a "success oriented" timeline today which assumes that the diver will show up as expected, the propeller swap fixes the problem and that I move 28 miles up Buzzards Bay to Onset. Yeah, that's a lot of "if."

I've used 50% of my water and was down to 1/2 tank of diesel. I know the GOM isn't the Atlantic ocean but I wanted to be topped off on everything. This morning, I maneuvered the boat over to the water and fuel docks which are separate. Wow, the vibration is absolutely no good. This is definitely not something to be ignored.

The good(?) news is, motoring in the calm harbor I was able to move freely about the boat to listen and feel. The vibration is most definitely coming from the very aft end of the boat, not the engine space. Right under the helm seat.  I don't see how it can be anything other than the propeller, cutlass bearing or the rudder and I really don't see how it could be the rudder.

New data point: My lovely bride brought both of my spare propellers, the fixed blade but also another Martec that I bought off Craigslist a few weeks ago. My plan was to send it off to be refurbished before ever using it.  In the comfort of my cabin, I was able to give it the @Zonker twist test and found that this propeller has much less play than the propeller that's installed right now.

I hope I'm looking at this objectively and not "leading the witness" because I hope that a propeller swap fixes my problem. I'm still planning on installing the fixed blade prop today.

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It sounds like you have done your due dilligance on this problem. Swaping the prop is probably the simplest next step, and and even if it does not fix the problem you have already determined the current prop needs a re-build anyway, so the expense of the swap is a wash. Most importantly I hope it solves the problem so you can get on with your cruise.

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Just closing this out:

The problem is fixed. The sloppy Martec was the problem. The fixed blade prop is pure smooth. The diver did say that my cutlass bearing has more wear than I thought it does so I'll replace it when I haul out in September. Cost me $150 for the diver.

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