Saildrive - for and against

maby said:
That does assume that you do it yourself - a day and a half labour in a half-decent boatyard is a significant cost!
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I assure you that at least 1/2 of that day was sat in the local restaurant deciding which way round the prop goes on .... I have the emails to prove it* ;)












* if requiring proof please give me 2 days to make them up ... er I mean find them ... :D
 
maby said:
Yes, that's prop walk. Strangely, the sailing community seems completely polarised on the issue - if your boat has it, it is useful, if your boart doesn't, it's a liability. Our boat has virtually no prop walk and I'm very pleased that it doesn't.
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As you mention, prop walk polarises the sailing community.

Mine has moderate starboard walk but gets stronger with a large throttle burst. Love to use this feature to moor precisely as I gently walk off the stern to a waiting bollard...:D
 
EugeneR said:
Just for interest, how much is "a bit more" per year, typically?
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Annual maintenance, little difference. Does not need an oil change every year and anode is variable - sometimes every year but my first one lasted 5 years in the Med. Possible seal change in the lower leg around £200 if part of a service. Diaphragm change is around £800 professional, £250 including oil change DIY. So average around £120 a year if you replace the diaphragm as recommended.
 
EugeneR said:
Just for interest, how much is "a bit more" per year, typically?
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Some years the outer rubber flange (not required for sealing at all) comes unstuck for a few inches so I use either some sikaflex or contact adhesive (whatever is to hand) to stick it back on when I'm doing the anti-fouling.

Each year I check the oil thru the oil dipstick on the sail drive unit, then suck a bit out with a suction pump to check it. Never had it even slightly discoloured so I leave it in and don't fret about changing it, which (with the 110s) can only really be done when the boat is out.

I check around the metal ring inside that compresses the main (inner) sealing gasket and wipe off any oil / diesel that is on it (it took me 15mins this year and I scratched my hand).

And that's it.

While the change interval for the inner seal is officially 7 years, I have never heard of even a weep from a seal as a first hand account, and I know from my local (much respected Volvo specialist) marine engineer that he has never seen one that he would be worried about. Tales of 12+ years are common, and then people usually change "just in case".

For sure changing it would be a right PITA on my boat, requiring it to be out on the hard and the engine to be lifted, but there is space for that so it isn't the end of the world.

And of course it wouldn't really be a whole day and a half of yard labour as someone posted, because the yard would know what they are doing, have the tools, and you would probably be doing some other work at the same time, like changing skin fittings or anti-fouling.

There is a strange snobbery about drive shafts, usually from those who look down their noses at AWB's/ Ben / Jen / Bav (or anything mass market) that hasn't been around the globe 20,000 times sailed by a hair-shirt boater who has spurned electricity and lives a parsimonious existence, steered purely by a wind vane made from an old biscuit tin ;)
 
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Sail drives are cheaper, less headaches and problems for the boat manufacturer, but dearer, more headaches and problems for the owner.
 
Why take a drive shaft that is turning in the right direction and turn it through 90degrees, poke it through the bottom of the boat, then turn it through another 90degrees back to the original direction? Seems a daft idea to me.

You probably gather that I'm not a fan of saildrives!
 
Seatrout said:
What is a 'P' bracket? They seem to be unreliable items given the frequency of my fellow club members cursing them. Saildrive-tastic!
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P bracket is one of the devices used to support a shaft that comes out of the boat at an angle. Became popular when bottoms of boats were flattened so there was nothing in the structure to support the shaft. Can be a problem - difficult to line up and sometimes not well attached to the structure. Hence now boats are getting older problems arise with bearing wear, vibration and bracket coming loose.

Almost out of "fashion" now in sailing auxilliaries replaced by superior saildrives or in some designs moulded in shaft logs.
 
What has not had a mention here is the cost that is associated with shaft drive maintenance. The P bracket bearing will need to be changed at least as often, if not more often as the seal on a sail drive, I suspect. You have to factor in if you cannot do the job yourself the cost of removing the prop, then the prop shaft, pressing out the bearing then getting the shaft lined up with gearbox again.

I do not know, but would guess that job would need to be done more regularly than changing the seal on a saildrive. Can anyone tell us?
 
As noelx has said, Saildrives are expensive to replace or mend, plus you have less scope to extemporise your repair in the average raggiedy arse boatyard.

There is little to jib about in a newish boat but it would be an extra worry in an old one. However it is not a deal stuffer.

Saildrives are nice and quiet unlike my propshaft.

PS

For Galadriel, cutless bearings seem to be changed between 3 years (me) 15 years and never depending who you speak to.
 
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galadriel said:
What has not had a mention here is the cost that is associated with shaft drive maintenance. The P bracket bearing will need to be changed at least as often, if not more often as the seal on a sail drive, I suspect. You have to factor in if you cannot do the job yourself the cost of removing the prop, then the prop shaft, pressing out the bearing then getting the shaft lined up with gearbox again.

I do not know, but would guess that job would need to be done more regularly than changing the seal on a saildrive. Can anyone tell us?
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Not sure how true this is - depends very much on how much use you make of the engine on a shaft drive boat. Unlike the shaft drive, the seal on a saildrive is going to degrade and need replacement even if the engine is never started. That's not to say that this is a deal breaker - the saildrive seal is relatively expensive to replace, but will last a fair few years.
 
I'm not sure how many years it takes for a saildrive seal to degrade. Like I said in my earlier post, mine was 17 years old when I changed it and was as good as the new one which replaced it.

doug748 reckons on between 3 - 15 years for cutlass bearing life (thanks doug, I could not remember what they were called!!). Having the yard change the saildrive seal is going to be expensive, I wont argue that, but if you have to employ them to change the cutlass bearing several times within the life of a saildrive seal, I suspect the arithmetic would be quite close in terms of overall cost.

I should point out, I have had two boats with saildrives and had no problems at all, I had one boat with a shaft and could not get rid of the vibration or drip from the packing.
 
doug748 said:
As noelx has said, Saildrives are expensive to replace or mend, plus you have less scope to extemporise your repair in the average raggiedy arse boatyard.
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Think that sums it up well, having gone through the expense of a complete new drive. However, this is a rare occurence and in my case not unconnected with 3500 hours and 7 seasons as a charter boat. Once it has failed, not economic to rebuild, not because it is technically difficult, but because failure, which is usually the clutch pack seizing or water getting in the bottom end, wrecks just about all the moving parts.

On the other hand the regular failings of some shaft drive installations can usually be fixed by changing one or two bits - cutless, shaft, engine mounts, couplings, shaft seals, which individually are not expensive and are easier DIY.

However, you could say similar things about older cars where many components could be replaced or repaired individually - but not possible on newer cars. My parents Ford Pop needed servicing every 1000 miles (17 shillings and sixpence) - but a decoke every 10000 miles, new clutch every 20000, new exhaust every 2 years etc, whereas my latest CMax diesel has run over 60000 miles with only oil changes, new pads and tyres and a battery after 7 years.

Newer style boats do not lend themselves to conventional shaft drives because of their flat underbodys. Saildrives keep the weight near the centre of the boat and do not require a heavy bulkhead/floor across the stern sections to take the P bracket, nor a vulnerable hole for the shaft to go through the bottom of the boat. Jeanneau are the last volume builder using P brackets and most of their newer models are using saildrives. Similar with Beneteaus who traditionally used a moulded shaft log but are now moving to saildrives - which are now available for up to 75hp engines.
 
I was a little tentative when before I purchased our Bavaria 40 Ocean with a sail drive. After getting used to the difference in handeling (the prop is right behind the keel -- not right in front of the rudder) the smooth quiet ride was easy to get used to. There is no cavitation and little prop walk (which I do miss a little). The prop walk isn't as big an issue since the bavaria has a fin keel and turns very quickly compared to my prior full keel boat that at time could have used a team of horses to manuever into a tight dock in a cross wind.

I just changed out the sail drive gasket this year (12 years). Here are a couple pics. I have a volvo saildrive. The gasket was in great shape and only showed slight signs of dry rot on the water side of the gasket. The gasket itself is really thick and very well built and would probably lasted many more years but I changed it out and not I don't have to worry about it for a while.

Would I purchase another boat with a sail drive .... abolutely yes. Just make sure to maintain it properly and you should have many years of good service. After all that's what we all want.
 
Clear insight

Comrade Red said:
There is a strange snobbery about drive shafts, usually from those who look down their noses at AWB's/ Ben / Jen / Bav (or anything mass market) that hasn't been around the globe 20,000 times sailed by a hair-shirt boater who has spurned electricity and lives a parsimonious existence, steered purely by a wind vane made from an old biscuit tin ;)
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I see Comrade Red has done a careful study of the forum psyche, and reached the view many of us hold of the prejudiced outlook many posters....... But where would we be without thse comfortingly predictable views that appear and let the rest of us feel superior with our progressive outlooks. Or in truth are we all as bad? Long live wooden boats (as long as someone else owns them )
 
Re: saildrive

Interesting no one has mentioned clutch life, i have first hand experience of poor life of yanmar cone clutches in the SD-40 , the yanmar book of jokes aka operating manual insists upon regular inspection and lapping of the clutch cone into the gear assembly , in addition the cruising forums are full of horror stories over failed clutches at 200 hours or so, incompetent service agents and outrageous spares costs e.g. £1000 or so for a new clutch pack , If I ever re-engine the boat, I would never use yanmar again because of sail drive issues.
 
njsail said:
I was a little tentative when before I purchased our Bavaria 40 Ocean with a sail drive. After getting used to the difference in handeling (the prop is right behind the keel -- not right in front of the rudder) the smooth quiet ride was easy to get used to. There is no cavitation and little prop walk (which I do miss a little). The prop walk isn't as big an issue since the bavaria has a fin keel and turns very quickly compared to my prior full keel boat that at time could have used a team of horses to manuever into a tight dock in a cross wind.

I just changed out the sail drive gasket this year (12 years). Here are a couple pics. I have a volvo saildrive. The gasket was in great shape and only showed slight signs of dry rot on the water side of the gasket. The gasket itself is really thick and very well built and would probably lasted many more years but I changed it out and not I don't have to worry about it for a while.

Would I purchase another boat with a sail drive .... abolutely yes. Just make sure to maintain it properly and you should have many years of good service. After all that's what we all want.
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I agree on the point about durability as I've just replace it myself as well. But there is one thing that bothers me.
Volvo uses stainless bolts to connect the upper side to the lower side. The way they do this induces corrosion at the lower part where the bolt heads are located. See enclosed picture. This was made after cleaning and before treatment with epoxy primer.

http://www.ybw.com/forums/attachment.php?attachmentid=17208&d=1333484492
 
aluijten said:
I agree on the point about durability as I've just replace it myself as well. But there is one thing that bothers me.
Volvo uses stainless bolts to connect the upper side to the lower side. The way they do this induces corrosion at the lower part where the bolt heads are located. See enclosed picture. This was made after cleaning and before treatment with epoxy primer.

http://www.ybw.com/forums/attachment.php?attachmentid=17208&d=1333484492
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I have replaced the seal on two different Volvos now, neither had corrosion like this, in fact there was no corrosion at all.
 
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