Saildrive or shaft?

Baggywrinkle said:
OK ... I'll bite.

Saildrive.....

Thrust parallel to direction of travel, prop walk minimal, maneuverability impeccable.
Vibration minimal, installation compact.

Fear over seal failure unfounded ... we trust our lives to pneumatic tyres daily and saildrive seals get orders of magnitude less abuse. Can't find any evidence of seal failure other than when everything is misaligned and the seal abused.

I've heard many tales of prop shaft vibration, problems with bearings, leaky seals, damp bilges and even shafts coming loose and jamming rudders or coming out completely.

Halberg Rassy abandoned shaft drive a number of years ago, saildrives are the future.

Downside is seal replacement ... but that's it IMO ;) .... I have a dry boat with bilges full of dust and a quiet, vibration and almost maintenance free propulsion system - except for seal replacement every 7 years.
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Plus 1
 
Baggywrinkle said:
I challenge you to find examples of saildrive seal failure ... for every seal failure you post, I'll post a shaft seal failure (with verifiable links).
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It's Andrew's rules number 1 & number 2 in play here...

1) I haven't got one, therefore it's sh*te/dangerous/unseaworthy/only for numpties

2) It was invented since 1970, therefore it's sh*te/dangerous/unseaworthy/only for numpties

Couldn't be a better example :)
 
AngusMcDoon said:
It's Andrew's rules number 1 & number 2 in play here...

1) I haven't got one, therefore it's sh*te/dangerous/unseaworthy/only for numpties

2) It was invented since 1970, therefore it's sh*te/dangerous/unseaworthy/only for numpties

Couldn't be a better example :)
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+1 .... I'm playing devil's advocate, I do have a boat with a saildrive but the boats I grew up on all had shaft drives. My next boat will have whatever is fitted after all my other requirements are met. It's not actually a deciding factor for me.
 
AngusMcDoon said:
It's Andrew's rules number 1 & number 2 in play here...

1) I haven't got one, therefore it's sh*te/dangerous/unseaworthy/only for numpties

2) It was invented since 1970, therefore it's sh*te/dangerous/unseaworthy/only for numpties

Couldn't be a better example :)
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And it's Angus' rules as usual, not reading the facts.

I had a boat with a saildrive, so chose to buy it; now I know better.

The Anderson 22 Mk 1 was first designed in 1973, my later version was built 1977 and modified with the latest kit I can afford or is suitable ever since.
 
Baggywrinkle said:
That prop failure could just have easily happened on a folding prop on a shaft? Sounds like a prop failure, not saildrive.

How often does a car tyre tear itself apart due to hitting something at 8mph? ... and a saildrive is normally travelling along sheltered behind a keel (except in a cat.).

I challenge you to find examples of saildrive seal failure ... for every seal failure you post, I'll post a shaft seal failure (with verifiable links) - see who runs out first. ;)



https://forums.sailboatowners.com/i...eller-shaft-fell-out-while-under-sail.144270/
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Re the prop snag, it was the nasty zinc cast boss of the Volvo saildrive which failed, you don't get those on shaft mounted folding props.

You needn't ' challenge ' me on numbers of failures, it's the concern that if anything drastic happens to a saildrive re the hull gasket it's very serious indeed and the boat would be unlikely to survive it.

I'm certainly not saying shafts are wonderful either, I knew someone who completed a 27' boat, on first trip when he selected reverse the shaft shot backwards, only prevented from going right out by the skeg; but few things are totally numpty-proof.
 
Having had both, I'd say I prefer maintaining a shaft but a saildrive is smoother and quieter in use as well as all but eliminating prop walk. Neither is perfect and both will suffer from poor maintenance or hitting something solid.

I agree with Baggywrinkle, if I like everything else about a boat I'm happy with either.
 
In my experience, saildrives are more trouble than shaft drives. Saildrives seem really good at getting blocked with weed (you see regular posts from people looking for help where they have steam coming out of the exhaust due to lack of water throughput). You have what is essentially a massive great anode hanging under the boat. There seem to be a lot of people losing props off saildrives, and then there's that big hole in the bottom of the boat. Then there's also the earthing issue, meaning that your engine is more expensive because it has to have an insulated earth.

WRT shaft drives, with the modern Volvo, Radice, of PSS shaft seals, there is really no maintenance needed. The components are cheap and easy to replace (shaft seal £100, cutlass bearing £50, shaft £300).

As far as vunerability is concerned, I would think that a huge great leg hanging under the boat would be must more vunerable than a shaft and P bracket.
 
Bobc said:
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As far as vunerability is concerned, I would think that a huge great leg hanging under the boat would be must more vunerable than a shaft and P bracket.
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I'm not so sure about that - saildrive incidents that have put the boat at risk are very rare. Friends of ours got a rope wrapped round the prop on their shaft drive Jenneau and the jerk as it tightened ripped the P bracket out - the boat was only saved with the rapid application of a big pump!

I do believe that the saildrive vulnerability is almost entirely imaginary. The gasket replacement schedule is primarily an insurance issue, not a real safety issue. When my insurer for our previous boat became aware that the gasket was overdue for replacement, they threatened to withdraw cover if it was not done soon - in practice we replaced the boat, not the gasket. The thing that causes me some concern about saildrives is the complexity and cost of routine maintenance and the eventual cost of replacement. Our current boat is just over a year old and I doubt that I have much more than ten years of sailing left in me, so I'm reasonably happy that it will see me out!

P.S. they are not "huge great legs" - the average saildrive is pretty small. All it is doing really is turning a 50HP inboard diesel into an outboard in a well.
 
I'd agree with Bobc that saildrives seem vulnerable to getting blocked; in my Carter 30 we were off Alderney in a flat calm when we went through a huge patch of green particle soup, plankton ?

Anyway the coolant guage shot up and alarm soon went off, we had to drift while taking the upper end of the inlet hose to filter off - the filter itself was clear - and put the dinghy pump on the hose to blast the stuff off the small intake holes in the saildrive leg.

This was fine on a calm sunny day, might not be on a dark night or if hazards were closer.
 
Bobc said:
In my experience, saildrives are more trouble than shaft drives. Saildrives seem really good at getting blocked with weed (you see regular posts from people looking for help where they have steam coming out of the exhaust due to lack of water throughput). You have what is essentially a massive great anode hanging under the boat. There seem to be a lot of people losing props off saildrives, and then there's that big hole in the bottom of the boat. Then there's also the earthing issue, meaning that your engine is more expensive because it has to have an insulated earth.

WRT shaft drives, with the modern Volvo, Radice, of PSS shaft seals, there is really no maintenance needed. The components are cheap and easy to replace (shaft seal £100, cutlass bearing £50, shaft £300).

As far as vunerability is concerned, I would think that a huge great leg hanging under the boat would be must more vunerable than a shaft and P bracket.
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Blocked with weed sounds a bit anecdotal to me, in the 7 years I've had mine it has never had this problem. Any strainer on a hull inlet can become blocked with fouling/weed ... don't see why a saildrive should be more prone to it than a normal cooling water inlet. In fact a saildrive saves you a through-hull fitting.

You have what is essentially a massive great anode hanging under the boat? - just like every MoBo with stern drives? .... some can be tilted but are often not completely out of the water. Neglect anything and it will fail - like my dads shaft drive Finnsailer 35 which lost a prop blade outside Tarbert in Argyll - prop became weak, we think due to dezincification and shed a blade - exactly the corrosion you are talking about? This is the only prop loss I have experienced personally in 40 years of sailing.

Expense? Don't buy that one either, complete re-power from fuel-lines to propeller cost me about €9K ... very similar to an equivalent shaft drive repower with everything new from fuel lines to propeller.

Cost of Volvo Penta Rubber Diaphragm Seal kit, £250 ... so a bit less than a shaft.

As for vulnerability, again ... it sits a few feet behind a keel (even on a cat as RichardS so kindly pointed out) and thousands of MoBos seem to manage with sterndrives travelling far faster than us raggies.

Bent "P" brackets anyone?

The P bracket on my SO362 sailboat is slightly bent causing shaft misalignment and rapid wear on the cutlass bearing. It is a bronze casting. Can I straighten it by applying heat (how much?) and bending back to shape, or will it fracture? In other words is it malleable or brittle?
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http://www.cruisersforum.com/forums/f114/bent-p-bracket-35598.html

I personally think your fears are unfounded and it's getting more and more difficult to find a modern production yacht without a saildrive.

This is definately a pointless debate, both systems work with pros and cons ... everyone has had different experiences but it would seem that instead of focussing on why their particular experience was bad and avoiding the same mistake again, it gets split into 2 camps slinging mud at their non-preferred option. I know I'm not going to change anyones mind, and that's fine, but I thought this thread started out as a saildrive bashing thread so I'm trying to bring some balance. I have no real preference, and many trouble-free years of saildrive ownership.
 
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jordanbasset said:
In the ten years I have owned 2 saildrive boats I have never had an issue with them being blocked with seaweed.
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I can double that to twenty and have never had a cooling problem due to weed. I have, though, picked up weed on the prop a number of times, invariably able to throw it off with reverse. I can't say the same for some fishing net near Jersey, but I imagine the same would apply with a shaft.
 
Anecdotally I have heard of baby mussels lodging themselves in the cooling intake of a sail drive. Not saying its common, just another thing that can happen. A Salcombe based boat, very regularly used.

Interesting about re-engining costs, are the holes standard sizes?

See the mobo forum for opinions about stern drives!
 
I think most of the points have been covered and people are just getting argumentative now.

I would prefer a shaft drive but when recently in the market for a boat the top contender on our shortlist had a saildrive. I didn't let that put me off as the boat sounded in great condition. But when we viewed, it transpired that the previous owner had for some reason bonded the saildrive to the seacocks and turned it into a big anode, and it was in need of complete replacement. Of course it was an obsolete model so I had concerns about whether a whole repower might be the sensible way forward.

This is only one anecdote but it's my only experience of saildrives and it hasn't helped to persuade me of their merits.
 
Baggywrinkle said:
Taken out and sold due to a worn out engine at 16 years, 4500 hrs. Boat was repowered with a VP D1-30 + new saildrive. Other than regular oil change, anode and anti-fouling it was still running problem free. Seal was changed once by me. Don't understand what people are afraid of. Aren't most problems down to neglected maintenance?

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Last year in service ....

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But my shaft drive is still running perfectly after 39 years. Same shaft. New cutlass bearing $160. Inner end complete plumber block $200. Why did you change the saildrive if it was so good?
 
geem said:
But my shaft drive is still running perfectly after 39 years. Same shaft. New cutlass bearing $160. Inner end complete plumber block $200. Why did you change the saildrive if it was so good?
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Yes sorry for butting in but that statment by Baggy does not hold well for saildrive longevity, 43 year old shaft drive with 5500 engine hours, with new cutless bearing when old wears out and good maintenance, I know nothing about saildrives but to compare I suspect there will be longivety in the shaft , which has had many many years to be perfected
 
People are fond of anecdotal stuff so another to consider is the failure of the P Bracket. On one boat I was helping to deliver there was so much vibration on the shaft we had to get a diver to look and found a fractured P Bracket. Quite expensive to lift out and sort
Not saying it is a regular problem but just google 'broken p bracket ybw' and you will see it is not rare and is one to factor in the mix
 
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