Never liked the idea of sail drives , that seal fails and your taking on huge amounts of water. All it takes is a nick in the paint on the leg and it becomes the anode, and The service cost of over $2000 times that by 2 if it's a cat amazes me why anybody would go with them .
www.cruisingworld.com/saildrive-maintenance/

This article is a very good read on sail drives
www.boats.com/reviews/all-about-saildrives/

Never had a seal fail, the closest was in a late 1990s Hobart when steaming to give assistance.
The heel was so great that the spinning prop would get into the air and hit the water on re entry at near full speed after revving in mid air for a bit with no resistance.
quite an impact when it hits the water.
After a about 4 hours of that the seal alarm went off.
Seems there was water between the two seals.
To silence the alarm we just pulled the sensor lead off.
I doubt a P bracket would have survived any better.
So difficult issue.
One boat has a sail drive and on does not.
Some say the sail drive is smoother but in reality a properly set up shaft and a balanced prop is just as good.

Does anyone know why saildrive carbon fibre lower legs haven't become the norm? I mean that would take care of my biggest concern which is the corrosion issue (also as related to useing copper antifoul).
With a quick search I could only find one company (electric motor) that does them.
I mean I've heard the same concerns over them being: corrosion, service cost and big hole in hull since they became mainstream so I thought the manufacturers would resolve these first.

Maybe I just gave someone a million dollar business idea .

Awkward.
Why do us simple folk come up with solutions when the specialists at the factories can't? (carbon fibre leg)
This also goes for things like tiller pilots where amateurs have produced limiters where again the in house engineers have not.

Back to saildrives.
I suspect the culprit in saildrives is a lack of proper maintenance.
As Lydia has said, "No problems here" would indicate. He has either been lucky or undertaken the correct maintenance.
As for the benefits of a saildrive: they allow the engine to be mounted much further astern than conventional systems.
More cabin space.
The minus point of this is that they are usually fitted in extremely tight locations making proper maintenance a difficult task.

In the long run I think they are an expensive solution to a problem that doesn't really exist.
I could be wrong though.

gary

I think another reason for the popularity in modern yachts is ease of production. The mounting of a saildrive is so much easier, much less demanding on the yacht builder. And as Garry eluded, they are more economical on space, for maximising cabin layouts. I have one and, touch wood no issues yet. I will replace the shaft seal this year, as a preventative maintenance task. I have seen them cop some abuse in charter yachts, if they can survive In that Market they can't be too bad. I coat the complete leg in prop speed, so no corrosion issue, the anodes seem to last pretty well, too! I think one area that all marine gearboxes seem to receive unmerciful abuse is gear selection. I notice some operators ramming the selector between forward & astern, without letting the engine revs settle. Just easing into gear allowing the prop to spool up is so much kinder, imho!
cheers Richard

Yacht on our local slips at the moment has a Volvo saildrive. Chatting to the owner yesterday while he was reassembling his after changing the seals. I noticed the anodes were the same as used on the sterndrives. I hope they are not as expensive as they used to be when I had a sterndrive! Apart from ensuring the saildrive and the area nearby is painted with hard antifoul they don't seem to be any more trouble than shaft drives. One big advantage with a saildrive over a shaft drive is there is no need to remove the rudder to pull the shaft to replace the bearings in a lot of shaft drive setups.

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Ramona said..
Yacht on our local slips at the moment has a Volvo saildrive. Chatting to the owner yesterday while he was reassembling his after changing the seals. I noticed the anodes were the same as used on the sterndrives. I hope they are not as expensive as they used to be when I had a sterndrive! Apart from ensuring the saildrive and the area nearby is painted with hard antifoul they don't seem to be any more trouble than shaft drives. One big advantage with a saildrive over a shaft drive is there is no need to remove the rudder to pull the shaft to replace the bearings in a lot of shaft drive setups.

If good seaman ship says keep the holes in the hull to a minimum having one that big which could sink you in minutes mitigates any arguments for a sail drive IMHO

My boat has a Volvo saildrive. I pulled the motor and saildrive last year to replace the hull boot at the recommended 7-year interval. Being a little D1-30 the motor removal was pretty easy as I have great access. The old boot looked to be in mint condition and I've heard online that they can still look good in the 10-15 year range. With Volvo's at least, I don't think you should have any concerns there. The replacement procedure probably took two days, but now that I've done it once, I reckon I could knock it off in a day. I can't remember the exact parts cost, I'm thinking $300-$400 ish for the boot and cover flap and anode, I'll see if I can find the receipt. The boat was out for anti fouling so it was just an extra couple of days hardstand cost.

My motor and saildrive are 7 years old and I couldn't see any untoward corrosion on the leg, and I stripped the old anti foul off so I was looking at it carefully. I reckon the horror stories and photos are likely derived from poor maintenance abuse. In order to pull the whole drive out of the boat, I had to disassemble and remove the lower leg gear and shaft, and that was pristine inside. At this point in time, if I was in the market for another boat, I wouldn't be put off by one with a saildrive, but I would do due diligence and check it out carefully. My mate has a mid 80's Adams with a shaft drive, and after a number of shaft vibration, seal and P-Bracket issues with that, he's looking at my saildrive in a more positive light.

One thing you have to look out for is shell growth inside the leg cavity, mine had a couple of good sized ones inside, so that's a negative I guess as they have the potential to block the cooling water galleys.

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2bish said..
My boat has a Volvo saildrive. I pulled the motor and saildrive last year to replace the hull boot at the recommended 7-year interval. Being a little D1-30 the motor removal was pretty easy as I have great access. The old boot looked to be in mint condition and I've heard online that they can still look good in the 10-15 year range. With Volvo's at least, I don't think you should have any concerns there. The replacement procedure probably took two days, but now that I've done it once, I reckon I could knock it off in a day. I can't remember the exact parts cost, I'm thinking $300-$400 ish for the boot and cover flap and anode, I'll see if I can find the receipt. The boat was out for anti fouling so it was just an extra couple of days hardstand cost.

My motor and saildrive are 7 years old and I couldn't see any untoward corrosion on the leg, and I stripped the old anti foul off so I was looking at it carefully. I reckon the horror stories and photos are likely derived from poor maintenance abuse. In order to pull the whole drive out of the boat, I had to disassemble and remove the lower leg gear and shaft, and that was pristine inside. At this point in time, if I was in the market for another boat, I wouldn't be put off by one with a saildrive, but I would do due diligence and check it out carefully. My mate has a mid 80's Adams with a shaft drive, and after a number of shaft vibration, seal and P-Bracket issues with that, he's looking at my saildrive in a more positive light.

One thing you have to look out for is shell growth inside the leg cavity, mine had a couple of good sized ones inside, so that's a negative I guess as they have the potential to block the cooling water galleys.

Nice write up

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Zzzzzz said..

Ramona said..
Yacht on our local slips at the moment has a Volvo saildrive. Chatting to the owner yesterday while he was reassembling his after changing the seals. I noticed the anodes were the same as used on the sterndrives. I hope they are not as expensive as they used to be when I had a sterndrive! Apart from ensuring the saildrive and the area nearby is painted with hard antifoul they don't seem to be any more trouble than shaft drives. One big advantage with a saildrive over a shaft drive is there is no need to remove the rudder to pull the shaft to replace the bearings in a lot of shaft drive setups.

If good seaman ship says keep the holes in the hull to a minimum having one that big which could sink you in minutes mitigates any arguments for a sail drive IMHO

That's very true Zzzzz, but I have a saildrive/engine bay that is sealed aside from the inlet fan (which has a valve to close off the duct).
.

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2bish said..


One thing you have to look out for is shell growth inside the leg cavity, mine had a couple of good sized ones inside, so that's a negative I guess as they have the potential to block the cooling water galleys.

If the boat is used regularly the water intake will stay clear.

If you're unlucky enough to have some fishing line wrap around your prop,and be unaware of it, not that unusual for a boat, you will be paying to slip it and for someone to replace the seals, give me a stern gland any day .

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Zzzzzz said..

Ramona said..
Yacht on our local slips at the moment has a Volvo saildrive. Chatting to the owner yesterday while he was reassembling his after changing the seals. I noticed the anodes were the same as used on the sterndrives. I hope they are not as expensive as they used to be when I had a sterndrive! Apart from ensuring the saildrive and the area nearby is painted with hard antifoul they don't seem to be any more trouble than shaft drives. One big advantage with a saildrive over a shaft drive is there is no need to remove the rudder to pull the shaft to replace the bearings in a lot of shaft drive setups.

If good seaman ship says keep the holes in the hull to a minimum having one that big which could sink you in minutes mitigates any arguments for a sail drive IMHO

+1

This video got me on board with sail drives. Seemed much easier to service than a shaft and more likely to be keep up to date.




A

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garymalmgren said..
Awkward.
Why do us simple folk come up with solutions when the specialists at the factories can't? (carbon fibre leg)
This also goes for things like tiller pilots where amateurs have produced limiters where again the in house engineers have not.

Back to saildrives.
I suspect the culprit in saildrives is a lack of proper maintenance.
As Lydia has said, "No problems here" would indicate. He has either been lucky or undertaken the correct maintenance.
As for the benefits of a saildrive: they allow the engine to be mounted much further astern than conventional systems.
More cabin space.
The minus point of this is that they are usually fitted in extremely tight locations making proper maintenance a difficult task.

In the long run I think they are an expensive solution to a problem that doesn't really exist.
I could be wrong though.

gary

Another big advantage of the sail drive is that the prop is spinning at 90 degrees. A shaft comes out the bottom of the boat on an angle so the prop is not directing all the water straight back but also down = lost drive.

The sail drive vs shaft drive argument can only be discussed in the context of which hull forms can either be fitted, which as most of us here would agree is the fin keeler.

That given, the next point is the angle of attack of the propellor. Someone smarter than I will have to post a comparison graph.

The next consideration is economic. Long term there can be no doubt that a shaft drive will cost less to maintain or replace than a sail drive.

I am for shaft drive any day purely for the simplicity of it.

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cisco said..


I am for shaft drive any day purely for the simplicity of it.

When they are simple yes. But how many have rudder and skeg set ups that require the removal of the rudder to get to the shaft. I was asked to adjust the stern gland on a yacht some time back. I could see the gland with a torch but it was out of reach. The very well installed furniture made access impossible. Other occasions I tried to get down through cockpit hatches but apparently my body is not the required shape. On my boat I can reach it easily with the pipe cot lifted out of the way and laying down. Engine on top of the keel and a short shaft would be my choice. Don't care about the angle. The boat would only be motoring around the moorings anyway.

though not a fan of saildrives if i were building a modern flat bottomed design i would use one as they have a lower drag profile are much cheaper to install keep all the engineering together on a heavy displacement or power boat i would stick with the shaft drive good angel for shaft simplicity no aloy to corrode

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boty said..
though not a fan of saildrives if i were building a modern flat bottomed design i would use one as they have a lower drag profile are much cheaper to install keep all the engineering together on a heavy displacement or power boat i would stick with the shaft drive good angel for shaft simplicity no aloy to corrode

Great argument for an outboard in a well seems to me a sail drive Is a very complicated and very expensive Version of a outboard.otherwise shaft drive.

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boty said..
though not a fan of saildrives if i were building a modern flat bottomed design i would use one as they have a lower drag profile

You might get more of a gain in drag reduction from a folding or feathering prop. Generally, a folding or feathering prop will give you an extra half knot. Would you get the same from a sail drive?

I would think a Volvo saildrive with a three blade folder would be the best hydro dynamically.