Sail-Drive in a Sailboat, Corbin 39'

[Captain Bill]

Originally Posted by Jim Cate

Actually, I think that they are indeed being fitted to yachts in the 40 foot +/- range. We had a dock neighbor in Hobart with a brand new AWB of that size which had such a device fitted. It didn't work,and his holiday cruise was aborted because there were no parts available in Oz at the time.

I was otherwise occupied at the time and didn't pursue it further... don't remember which sort of AWB it was, but French sticks in my mind.

But I agree that it is not likely that the subject Corbin would have such a thing!

Jim

You are correct, see the link below.

Jeanneau sailboats 360 Docking system

[smj]

Originally Posted by Jim Cate

Mark, you seem to have a hard time accepting anything I say, so I went back into my logbook and checked. The AWB in question was a brand new Jeanneau 379. It had some manner of rotating saildrive sort of propulsion, and an engine of appropriate size for the boat. It did not work at the time, and I did not go aboard to inspect it, as we were frantically preparing to leave our boat and fly to the States. I didn't record all the details then, so I went to the factory brochure which describes the unit, which was fitted to a 29 hp Yanmar:

"The concept is simple: the engine is coupled with
a pivoting sail drive, capable of rotating 360°. The
joystick transmits the commands to a control box,
which uses the autopilot to lock the helm. Then,
a simple movement of the joystick controls the
orientation and the thrust of the pod, as well as
the bowthruster."

I don't know if you will accept this, but most folks would.

Jim

I know it's true, saw a video on YouTube showing its maneuverability capabilities.

We owned a cat that had Yanmar saildrives and never had a problem. But no they are not on my list of must haves, probably the opposite as I do see quite a few problems as compared to shaft drive diesels.

[colemj]

Jim, I wasn't disbelieving what you wrote, I simply did not know what a AWB was and thought you were referring to some type of smaller powerboat. I am amazed that my WAG of "Average White Boat" was actually correct!

Yes, what you described is Benetau's "dock and go" system that does have a rotating saildrive coupled with bow thruster. That system never worked and I thought it was dropped. I vaguely remember a boat being lost when that system activated itself in some bad weather and drove a boat into a jetty or something like that!

It is only available on Benetau/Jeaneau and not commercially available to others.

I forgot all about that system and was thinking more of the commercially available systems that do work like the Volvo ISP.

My apologies that you took me for calling you a liar - that wasn't the case at all. I admit that there are sailboats with these systems. I wouldn't want to own one though…

Edit: here it is: http://www.sailnet.com/forums/genera...doors-hal.html

Mark

[Kevin84]

Originally Posted by colemj

It doesn't have to be a lie to be wrong. There is no physical or electrical way dredging the bottom and increased temperature caused saildrive corrosion. It simply is not possible.

Plugged into shore power? Hmmmm….

Mark

That's not entirely correct Mark. Though not entirely wrong either. The dredging could have caused a localized increase in the salinity or alkalinity of the water which, when coupled with either a bad ground on the boats in question or a faulty ground in the marina's power supply could have caused the corrosion. The electric current bleeding into the marina would also have increased the water temperature. Combine those elements and you get an electro-chemical reaction.

The other possibility is far simpler and (IMHO) far more likely. Chemical contamination of the harbor floor from industrial run off or dumping. If this run off or dumping took place prior to the marina being built there, the contaminates would have been covered by silt in the years since. The dredging then uncovered and stirred up the chemicals causing the corrosion.

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[colemj]

Originally Posted by Kevin84

That's not entirely correct Mark. Though not entirely wrong either. The dredging could have caused a localized increase in the salinity or alkalinity of the water which, when coupled with either a bad ground on the boats in question or a faulty ground in the marina's power supply could have caused the corrosion. The electric current bleeding into the marina would also have increased the water temperature. Combine those elements and you get an electro-chemical reaction.

The other possibility is far simpler and (IMHO) far more likely. Chemical contamination of the harbor floor from industrial run off or dumping. If this run off or dumping took place prior to the marina being built there, the contaminates would have been covered by silt in the years since. The dredging then uncovered and stirred up the chemicals causing the corrosion.

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Nope, I'm still calling BS. Electric current bleeding into the water increases the water temperature? That is basic thermodynamics and will not happen. Well, assuming one hasn't terminated the local transfer station output directly into the water. Likewise, increasing the salinity or alkalinity will not happen either - salinity because of dilution and dynamics, alkalinity because of buffering.

Besides, do you really think saildrives in boats in waters that are naturally more alkaline or salty than that marina are corroding left and right?

Anything "localized" enough will be so short lived as to not be an issue at all. How fast do you think marine grades of primed, coated and zinc-protected aluminum corrodes?

Chemical contamination from the dredging causing the corrosion is also a no-go. I'm a chemist - trust me on that. If you can't, then at least supply a rationale or mechanism how it could happen. Simply saying "chemicals" is not enough.

The far easier explanation is that there was poor marina wiring and/or poor electrical systems in the boats that worked over time to cause the corrosion problem. This was a problem going on for a while and had absolutely nothing at all to do with the dredging outside of coincidental timing.

Mark

[Kevin84]

Originally Posted by colemj

Nope, I'm still calling BS. Electric current bleeding into the water increases the water temperature? That is basic thermodynamics and will not happen. Well, assuming one hasn't terminated the local transfer station output directly into the water. Likewise, increasing the salinity or alkalinity will not happen either - salinity because of dilution and dynamics, alkalinity because of buffering.

Besides, do you really think saildrives in boats in waters that are naturally more alkaline or salty than that marina are corroding left and right?

Anything "localized" enough will be so short lived as to not be an issue at all. How fast do you think marine grades of primed, coated and zinc-protected aluminum corrodes?

Chemical contamination from the dredging causing the corrosion is also a no-go. I'm a chemist - trust me on that. If you can't, then at least supply a rationale or mechanism how it could happen. Simply saying "chemicals" is not enough.

The far easier explanation is that there was poor marina wiring and/or poor electrical systems in the boats that worked over time to cause the corrosion problem. This was a problem going on for a while and had absolutely nothing at all to do with the dredging outside of coincidental timing.

Mark

Mark, there are so many variables here that we don't know about, it could be any one of these things.

And also, I never said it was JUST the salinity or JUST the alkalinity. However, (if memory of my chem lab serves me right) increased salinity or alkalinity can increase electrical conductivity, which in turn could increase corrosion. Besides, we don't know if the two saildrives in question were properly coated with primer and paint. How many times have you heard of a yard guy painting a saildrive with a paint that's corrosive to aluminum? I've known a few people that had that problem. Same with the zincs on the boats. We don't know if they even had any or what shape they were in.

Look, at this point we're just spitballing since there are a lot of factors that we just don't know. Any of what you or I suggested could be either a cause or a contributing factor. One thing I do find telling though is the marina's reaction to all this. They must be fairly certain that the dredging played at least a small role in the damage. Otherwise why would they voluntarily pay for repairs?

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[ontherocks83]

Originally Posted by colemj

No, they don't work that way - they are fixed just like a shaft drive.

Interesting that you responded with many "facts" about saildrives, but do not even know how they work. In short, your understanding of them having a drastic increase in the number of failures possible, as well as ton more moving parts and a lot more maintenance requirements is also wrong.

Mark

Funny how Jeanneau offers/offered this system in far less then 250 hp (who has the "facts now?). I am wrong that they all rotate 360 degrees, but considering they are essentially a speed boat out drive completely underwater they are a lot more complex then a straight drive shaft and have the potential to have more failure points.

Its "interesting" how you know that pods are only available in 250hp and up but yet they are not. Thankfully i have enough humility to know i could be wrong. Hopefully one day i will be smart enough to not need humility like you. Or will I?

[Captain Bill]

Originally Posted by ontherocks83

Funny how Jeanneau offers/offered this system in far less then 250 hp (who has the "facts now?). I am wrong that they all rotate 360 degrees, but considering they are essentially a speed boat out drive completely underwater they are a lot more complex then a straight drive shaft and have the potential to have more failure points.

Its "interesting" how you know that pods are only available in 250hp and up but yet they are not. Thankfully i have enough humility to know i could be wrong. Hopefully one day i will be smart enough to not need humility like you. Or will I?

I have two saildrives and let me assure you they are nothing like speedboat outdrives. If they were we would not have nearly so much trouble with them. If they were just built like outboard lower unit they would be nearly bulletproof compared to these pieces of junk that Yanmar has been selling. Maybe their new sd60 will be an improvement, but that remains to be seen. The under water part is not their weak point, it's what Yanmar tries to pass off as a transmission that is the primary problem. The old SD20 saildrives which are built like an outboard lower unit are very dependable and have been around for a long time. If the boat the OP looked at has an SD20 then it's probably ok. The only bad thing about the SD20 is that you can't change the oil from inside the boat.

That being said I know a lot of people with shaft drives and they have issues with cutlass bearing, packing glands, dripless seals, oil coolers, shaft alignments and yes, even blown transmissions. I once hit a crab pot line at night with a shaft drive. The shaft coupling broke, the shaft got pulled back and jammed the rudder, water was pouring through the shaft seal. I had to go overboard at night to cut the line off and free up the shaft so I could push it back forward. I had to lash it in position to stop it from pulling back out and jamming the rudder again. I then had to stuff rags around the shaft to slow the leak down. Fortunately the bilge pumps were able to keep up with the inflow. But be assured that shaft drives are almost problem free. I see that here on CF all the time.

[colemj]

Originally Posted by ontherocks83

Funny how Jeanneau offers/offered this system in far less then 250 hp (who has the "facts now?). I am wrong that they all rotate 360 degrees, but considering they are essentially a speed boat out drive completely underwater they are a lot more complex then a straight drive shaft and have the potential to have more failure points.

Its "interesting" how you know that pods are only available in 250hp and up but yet they are not. Thankfully i have enough humility to know i could be wrong. Hopefully one day i will be smart enough to not need humility like you. Or will I?

OK, whatever. These pod drives are not saildrives. You can say they are, as you just said stern drives (outdrives) are the same. That doesn't make it true. A traditional saildrive is not much more complex than a traditional shaft drive nor do they have so many more potential failure points. For example, Volvo's saildrive transmission and shaft drive transmissions for their small diesels are exactly the same mechanics with the exception that the saildrive has a longer shaft connecting the forward/reverse gearing with the driveshaft gearing.

Benetaeu group is the only manufacturer offering the small pod system you mention, which is manufactured just for them, and that system has been a complete cockup, so I wouldn't place it in the same category as other pod drives which have been working just fine for many years.

And it certainly is a long way removed from old-time standard saildrives.

Mark

[colemj]

Originally Posted by Captain Bill

I have two saildrives and let me assure you they are nothing like speedboat outdrives. If they were we would not have nearly so much trouble with them. If they were just built like outboard lower unit they would be nearly bulletproof compared to these pieces of junk that Yanmar has been selling. Maybe their new sd60 will be an improvement, but that remains to be seen. The under water part is not their weak point, it's what Yanmar tries to pass off as a transmission that is the primary problem. The old SD20 saildrives which are built like an outboard lower unit are very dependable and have been around for a long time. If the boat the OP looked at has an SD20 then it's probably ok. The only bad thing about the SD20 is that you can't change the oil from inside the boat.

That being said I know a lot of people with shaft drives and they have issues with cutlass bearing, packing glands, dripless seals, oil coolers, shaft alignments and yes, even blown transmissions. I once hit a crab pot line at night with a shaft drive. The shaft coupling broke, the shaft got pulled back and jammed the rudder, water was pouring through the shaft seal. I had to go overboard at night to cut the line off and free up the shaft so I could push it back forward. I had to lash it in position to stop it from pulling back out and jamming the rudder again. I then had to stuff rags around the shaft to slow the leak down. Fortunately the bilge pumps were able to keep up with the inflow. But be assured that shaft drives are almost problem free. I see that here on CF all the time.

Bill, your experiences with stern drives are certainly better than mine, and better than the forums full of people complaining about them.

To be fair, though, one cannot paint saildrives in general with a Yanmar brush. Yanmar's SD40/50 drives are very problematic and not representative of any of the Volvo saildrive models, or even the Yanmar 20/30 drives.

And then it is not even the transmission part that is the problem - it is the clutch mechanism. I never have figured out why that is such a bad one on those drives.

BTW, there are absolutely no problems with shaft drives - you are way off base there. Funny, our last haulout saw the yard with ~50/50 shaft/saildrive boats. None of the saildrives had any problems with them while 6 (representing almost half) of the shaft drive boats had one or more of the following: bad cutlass bearings, bad intermediate bearings, bad couplings, bad strut, bad engine alignment and/or blown transmission.

I personally do not see those samples as turning me off shaft drives or suggesting people stay away from them.

Mark

[smj]

[QUOTE=colemj;1550538]OK, whatever. These pod drives are not saildrives. You can say they are, as you just said stern drives (outdrives) are the same. That doesn't make it true. A traditional saildrive is not much more complex than a traditional shaft drive nor do they have so many more potential failure points. For example, Volvo's saildrive transmission and shaft drive transmissions for their small diesels are exactly the same mechanics with the exception that the saildrive has a longer shaft connecting the forward/reverse gearing with the driveshaft gearing.



Benetaeu group is the only manufacturer offering the small pod system you mention, which is manufactured just for them, and that system has been a complete cockup, so I wouldn't place it in the same category as other pod drives which have been working just fine for many years.



And it certainly is a long way removed from old-time standard saildrives.



Mark[/

I for one can't see a saildrive as having less failure points of a shaft drive.


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[colemj]

Originally Posted by Kevin84

Mark, there are so many variables here that we don't know about, it could be any one of these things.

And also, I never said it was JUST the salinity or JUST the alkalinity. However, (if memory of my chem lab serves me right) increased salinity or alkalinity can increase electrical conductivity, which in turn could increase corrosion. Besides, we don't know if the two saildrives in question were properly coated with primer and paint. How many times have you heard of a yard guy painting a saildrive with a paint that's corrosive to aluminum? I've known a few people that had that problem. Same with the zincs on the boats. We don't know if they even had any or what shape they were in.

Look, at this point we're just spitballing since there are a lot of factors that we just don't know. Any of what you or I suggested could be either a cause or a contributing factor. One thing I do find telling though is the marina's reaction to all this. They must be fairly certain that the dredging played at least a small role in the damage. Otherwise why would they voluntarily pay for repairs?

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Yes, we are just spitballing. However, even an uncoated, unzinced saildrive will not corrode from stirred up, salty, alkaline, chemically and bacterially contaminated warm water. It just is not the reason. How much more "electrically conductive" can you make a large expanse of changing seawater, and where would the electricity come from?

The dredging played no role in this unless it was due to their ships being plugged in next to other boats and having really bad wiring.

However, the wrong paint, forgetting the zincs, bad wiring, etc could easily be the reason. Could also be why the yard is paying for it…

Mark

[colemj]

Originally Posted by smj

Mark[/

I for one can't see a saildrive as having less failure points of a shaft drive.


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I never said they did have less. I did say they do not have "drastically" more points of failure or a "ton" more moving parts than shaft drives.

Mark

[Captain Bill]

Originally Posted by colemj

Bill, your experiences with stern drives are certainly better than mine, and better than the forums full of people complaining about them.

To be fair, though, one cannot paint saildrives in general with a Yanmar brush. Yanmar's SD40/50 drives are very problematic and not representative of any of the Volvo saildrive models, or even the Yanmar 20/30 drives.

And then it is not even the transmission part that is the problem - it is the clutch mechanism. I never have figured out why that is such a bad one on those drives.

BTW, there are absolutely no problems with shaft drives - you are way off base there. Funny, our last haulout saw the yard with ~50/50 shaft/saildrive boats. None of the saildrives had any problems with them while 6 (representing almost half) of the shaft drive boats had one or more of the following: bad cutlass bearings, bad intermediate bearings, bad couplings, bad strut, bad engine alignment and/or blown transmission.

I personally do not see those samples as turning me off shaft drives or suggesting people stay away from them.

Mark

The problems that I am aware of people having with stern drives have been with the rubber seal to the hull, the universal joints, and the hydraulic tilt, and steering mechanisms. The foot of the unit has been pretty dependable. Since a saildrive has none of the "problem" parts they should be just as dependable as the foot of the stern drive.

I unfortunately am quite familiar with the inner workings of a Yanmar SD40/50 and was referring to the cone clutches when I said "What they pass off as a transmission" That is the only thing in them that resembles a transmission. The rest is just a couple of bevel gears on shafts and the bearings to hold them in alignment.

I should have said SD20/30 and agree they are just fine. I have several friends with Volvo saildrives and they don't seem to have much trouble with them, though parts cost seem outrageously expensive, even worse than Yanmar.

My last haulout was to replace a leaking prop shaft seal so I would have created a small problem with your stats. I did the whole job on both drives in less than 4 hours. The yard owner asked me if I wanted a job. I told him I had a full time job repairing one boat, I couldn't do any more.

[Captain Bill]

Originally Posted by colemj

I never said they did have less. I did say they do not have "drastically" more points of failure or a "ton" more moving parts than shaft drives.

Mark

I'm not sure I agree with you mark. I could be convinced that saildrives in general have less failure points than shaft drives. I would guess the parts count is just about the same when you count them from engine to propeller. You are going to have a shift mechanism that couples the input shaft to the output shaft. Both of those shafts will have supporting bearings. On some you will have an oil pump that pumps the transmission oil through a heat exchanger. The foot of a sail drive serves this purpose because it is continiously immersed in cool water. The final drve seals and bearings are continously soaked in a lubricating oill bath, unlike the shaft seals, cutlass bearing and sometimes and intermediate bearing which are all exposed. The longest shaft in the saildrive is the vertical shaft connecting the transmission to the outdrive and it is also bathed in oil. The shaft of the saildrive is fixed in position relative to the engine so you don't have any failures associated with alignment. A well executed saildrive should be quite superior to a shaft drive. The only problem now is finding a well executed saildrive. I certainly don't have one. My SD40's can only be decribed as junk. The input shaft and output shafts are made of such soft metal that I once had an unrepairable groove worn into one by an oil seal in less than 100 hours.