In a thread a few days ago, there were several negative remarks about saildrives, suggesting that it was risky to have such a large hole in the hull, with only two rubber seals to keep the water out. Is this risk real? Or is it mostly fear of something new? Can anyone point to any documented, catastrophic failures of saildrives?
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sail drive skeptic
Dear Skeptic, sail drives have there problems just like any other drives system does. There a lots of sail drives that have been around for a long time.there have been problems with the seal and other have had no problems at all. IOM (for what it is worth)there is not much difference in the odds that the sail drive seal fail then a pss shaft seal or a stuffing box seal fail.They have all failed but not so much that no one uses them,nor has any one developed a "failproof" system.Saildrive have there advantage,one being they are more compact and have space advantages on conventional shaft systems.some think they are a plus in that they don't have as much "drag" (when under sail)as a shaft and strut design.They are mounted farther forward of the rudder so they take a little longer to put water over the rudder,not a big issue unless close quarters handleing is a big issue for you.The big issue is (as in most mechanical things) maintance! ! They need have the oil changed(this requires the boat be hauled)zinc replacement (prop needs to be removed sometimes)Here is the big one ! The seal has a recomended replacment of SEVEN years !Alot of boat with sail drive will need to have the engine removed in order to replaced the seal. SOO the cost factor becomes a issue !I would not be afraid of a sail drive if you are the type who will do (or have done) the maintance on schedule.the same could be said of any drive system. I don't know of any documented failures of the seals vs other failures.The seals got a bad reputation years ago when a inboard/outboard mfg used them in the transom and had some failures.It is hard to blame a mgf for a failure when mfg service interval are not preformed. In short if you service it (according to mfg) it should last a long long time.All that being said it would not be my first choice,I still prefer the shaft and strut design for simplicity !
Dear Skeptic, sail drives have there problems just like any other drives system does. There a lots of sail drives that have been around for a long time.there have been problems with the seal and other have had no problems at all. IOM (for what it is worth)there is not much difference in the odds that the sail drive seal fail then a pss shaft seal or a stuffing box seal fail.They have all failed but not so much that no one uses them,nor has any one developed a "failproof" system.Saildrive have there advantage,one being they are more compact and have space advantages on conventional shaft systems.some think they are a plus in that they don't have as much "drag" (when under sail)as a shaft and strut design.They are mounted farther forward of the rudder so they take a little longer to put water over the rudder,not a big issue unless close quarters handleing is a big issue for you.The big issue is (as in most mechanical things) maintance! ! They need have the oil changed(this requires the boat be hauled)zinc replacement (prop needs to be removed sometimes)Here is the big one ! The seal has a recomended replacment of SEVEN years !Alot of boat with sail drive will need to have the engine removed in order to replaced the seal. SOO the cost factor becomes a issue !I would not be afraid of a sail drive if you are the type who will do (or have done) the maintance on schedule.the same could be said of any drive system. I don't know of any documented failures of the seals vs other failures.The seals got a bad reputation years ago when a inboard/outboard mfg used them in the transom and had some failures.It is hard to blame a mgf for a failure when mfg service interval are not preformed. In short if you service it (according to mfg) it should last a long long time.All that being said it would not be my first choice,I still prefer the shaft and strut design for simplicity !
The brand new C&C 99 has Sail Drive
Yessir. They decided that it would make for a faster boat - and wow - it did. Robert Perry - the famous boat designer - applauds the use of sail drives.
Yessir. They decided that it would make for a faster boat - and wow - it did. Robert Perry - the famous boat designer - applauds the use of sail drives.
Designers love saildrives...
...as do builders. I don't believe that automatically makes boat owners into happy campers. A couple of other points... 1. There is no 'maintenance' related to the saildrive's diaphram, other than a visual inspection of the very small portion of that seal one can see. The manufacturer of that product has taken a position on its service life...and whether it's a cautious and conservative estimate or a more appealing and agressive one, all saildrive owners will eventually face a choice between engine lift and chock or full removal in order to replace the diaphram. When I ask mechanics about this task, they get real 'iffy' about whether they would want to do this work. Perhaps one reason is because most owners ignore the recommended replacement sked, as I find few mechanics who have ever done one. Perhaps it's also because they begin picturing the removal of ferrous steel bolts from an aluminum case after many years in the presence of salt water... 2. I dislike the analogy of of a stuffing box being as failure prone as a saildrive diaphram. As one illustration, if a saildrive prop catches a line that's attached to something that doesn't want to give readily (secured dockline, fishing net or such), you've got a lot of force being directed at the end of a lever (the saildrive leg), and the degree to which the seal is torn, ruptured or suffers no damage is an unknown...but the continuum of possibilities is quite broad. If a conventional shaft's prop takes the line, it can wrench the strut, break the engine mounting bolts, etc. but the stuffing box is unlikely to be affected in the least. 3. When I asked Volvo factory reps what they see being problematic, they had lots of examples. Snaking a tube down the gear leg to suck out oil, only to have the tube snare the gears and disable the leg, was one happy event which they mentioned. All that aluminum serving as an anode if the owner fails to monitor and replace zincs was another. I wish I'd thought to ask about the diaphram issue, as it would have been useful to hear their answer...including what they recommend when the owner of an older Volvo installation who needs a new diaphram calls them only to find Volvo doesn't offer it anymore. I've made some discouraging remarks about saildrives here and elsewhere, but it's not because they don't offer some advantages. I guess my main gripe is that the possible problems can be relatively catastrophic when compared to a conventional powertrain, but that the commerical periodicals, the builders, the brokers and even 'watchdog' industry groups fail to even whisper about the bad along with the good. The article in Feb's SAIL is a classic example. Thus, the value of discussion on this topic on boards like this one. Jack
...as do builders. I don't believe that automatically makes boat owners into happy campers. A couple of other points... 1. There is no 'maintenance' related to the saildrive's diaphram, other than a visual inspection of the very small portion of that seal one can see. The manufacturer of that product has taken a position on its service life...and whether it's a cautious and conservative estimate or a more appealing and agressive one, all saildrive owners will eventually face a choice between engine lift and chock or full removal in order to replace the diaphram. When I ask mechanics about this task, they get real 'iffy' about whether they would want to do this work. Perhaps one reason is because most owners ignore the recommended replacement sked, as I find few mechanics who have ever done one. Perhaps it's also because they begin picturing the removal of ferrous steel bolts from an aluminum case after many years in the presence of salt water... 2. I dislike the analogy of of a stuffing box being as failure prone as a saildrive diaphram. As one illustration, if a saildrive prop catches a line that's attached to something that doesn't want to give readily (secured dockline, fishing net or such), you've got a lot of force being directed at the end of a lever (the saildrive leg), and the degree to which the seal is torn, ruptured or suffers no damage is an unknown...but the continuum of possibilities is quite broad. If a conventional shaft's prop takes the line, it can wrench the strut, break the engine mounting bolts, etc. but the stuffing box is unlikely to be affected in the least. 3. When I asked Volvo factory reps what they see being problematic, they had lots of examples. Snaking a tube down the gear leg to suck out oil, only to have the tube snare the gears and disable the leg, was one happy event which they mentioned. All that aluminum serving as an anode if the owner fails to monitor and replace zincs was another. I wish I'd thought to ask about the diaphram issue, as it would have been useful to hear their answer...including what they recommend when the owner of an older Volvo installation who needs a new diaphram calls them only to find Volvo doesn't offer it anymore. I've made some discouraging remarks about saildrives here and elsewhere, but it's not because they don't offer some advantages. I guess my main gripe is that the possible problems can be relatively catastrophic when compared to a conventional powertrain, but that the commerical periodicals, the builders, the brokers and even 'watchdog' industry groups fail to even whisper about the bad along with the good. The article in Feb's SAIL is a classic example. Thus, the value of discussion on this topic on boards like this one. Jack
omc answer
I asked this forum about OMC saildrives last fall ... below, from the archives, is the best answer. Response to OMC saildrive?: i researched this 5 yrs ago... Submitted by Steve W. on 10/07 at 01:33PM regarding General_interest and bottom line, if running & not leaking, they won't be soon. OMC mechanics told me that the leg corodes internally, looks great on the outside, but not the inside and there are no new replacement legs available. The hull/engine seal is no longer available, either. Boat has to be hauled to replace the impeller and change lower unit gear oil, too. I was looking at an S-2 and the broker recomended making the offer based on replacing with an outboard and a stern mount, even though the OMC ran great. Passed on the boat, but heard the new owner had seal & leg problems & did go with an outboard. Hope this helps.
I asked this forum about OMC saildrives last fall ... below, from the archives, is the best answer. Response to OMC saildrive?: i researched this 5 yrs ago... Submitted by Steve W. on 10/07 at 01:33PM regarding General_interest and bottom line, if running & not leaking, they won't be soon. OMC mechanics told me that the leg corodes internally, looks great on the outside, but not the inside and there are no new replacement legs available. The hull/engine seal is no longer available, either. Boat has to be hauled to replace the impeller and change lower unit gear oil, too. I was looking at an S-2 and the broker recomended making the offer based on replacing with an outboard and a stern mount, even though the OMC ran great. Passed on the boat, but heard the new owner had seal & leg problems & did go with an outboard. Hope this helps.
Profligate's sail drives
Profligate, Latitude 38’s big cat, lost both of her sail drives on her way from Cabo San Lucas to the Caribbean this past November-December. She required a haul out on the Pacific side of Panama wherein they were both replaced, requiring mounting modifications and fiberglass work. She was again hauled in January in the Carib to correct problems resulting from the install. I believe that the sail drives were either replaced or rebuilt when she was in San Diego prior to the trip.
Profligate, Latitude 38’s big cat, lost both of her sail drives on her way from Cabo San Lucas to the Caribbean this past November-December. She required a haul out on the Pacific side of Panama wherein they were both replaced, requiring mounting modifications and fiberglass work. She was again hauled in January in the Carib to correct problems resulting from the install. I believe that the sail drives were either replaced or rebuilt when she was in San Diego prior to the trip.
Is this risk real?
Skeptic Yes, it is. If you read the recent magazine article, and look at how it is made and where the weak points are, it'd be hard to convince an engineer (or skipper) that there is not a single piont of failure risk right there inherent in the design. Sure, we all have stern tubes and packing glands, but the pint is that they are simple, and have been around for hundreds, if not more, years. They leak unless you do something about the material in the box, but they are basic, simple and work (given some maintenance). The people who complain about them are the people who don't want to or care to learn about them. I love new technology. But only when it works and is NOT accompanied by a glossy atricle that shouts: "We been fu*king up for years, so we solved "some" of the problem, so we're now OK." Malarkey. I just wouldn't buy that particular bridge from those guys. Stu
Skeptic Yes, it is. If you read the recent magazine article, and look at how it is made and where the weak points are, it'd be hard to convince an engineer (or skipper) that there is not a single piont of failure risk right there inherent in the design. Sure, we all have stern tubes and packing glands, but the pint is that they are simple, and have been around for hundreds, if not more, years. They leak unless you do something about the material in the box, but they are basic, simple and work (given some maintenance). The people who complain about them are the people who don't want to or care to learn about them. I love new technology. But only when it works and is NOT accompanied by a glossy atricle that shouts: "We been fu*king up for years, so we solved "some" of the problem, so we're now OK." Malarkey. I just wouldn't buy that particular bridge from those guys. Stu
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