sail drive v shaft on 38 - 40 ft yacht

[cloud7]

Forum opinion greatly appreciated : in our search for a 38ft to 40ft replacement yacht the sail drive v shaft issue has arisen , looking at the dufour range they go for the sail drive option , what the view on the forum on this choice , thks

 

[Twister_Ken]

If you're looking for a new mass-manufacturer boat, you'll have some difficulty finding a shaft drive. I believe a few Bennies have them, but most builders opt for saildrives. I suspect economics of manufacture drive the decision, rather than more seamanlike considerations.

 

[davidwf]

Had both, I think I favour sail drive as lots less prop walk due to it being farther forward, downside would be that it needs more care re anodes etc. But then I have had a shaft corrode so I think theres not much in it really.

Nearly forgot you do have to cahnge the seal on the Sail drive every 7 years so thats additional expense.

 

[sighmoon]

We're hoping to buy a boat with shaft drive (not that it's a criteria), but what scares me is that if the coupling fails, and the shaft falls out, we'll have a large hole in the bottom of the boat.

 

[Malish]

We're hoping to buy a boat with shaft drive (not that it's a criteria), but what scares me is that if the coupling fails, and the shaft falls out, we'll have a large hole in the bottom of the boat.

Your nerves can easily be realxed by clamping a jubilee clip to the shaft inside the boat - that will stop a unexpected shaft loss. (Put two at 180 degrees to each other for balance and even greater piece of mind). On my boat, even if the shaft tried to do a runner, it would be hard pushed to get past the skeg.

 

[Tranona]

For the builder there is not much in it in cost. Up until recently just about all Bennys and Jennies used shafts and just about everybody else used saildrives. However, new models are tending toward saildrives and with the larger sizes new designs that rotate.

The advantages of saildrives for the user are quieter, smoother and minimum prop walk because the prop is usually well away from the rudder and thrust is parallel to the waterline. Downsides are some delay before propwash hits the rudder, potential corrosion - although latest designs have larger anodes and arguably higher maintenance or perhaps greater penalty for neglect.

Saildrives are not new technology - they have been around for nearly 30 years and are well understood.

 

[savageseadog]

Saildrive, no question.

There's drawbacks to both systems but many more advantages to a saildrive.

Do:
Use recommended oil
Change the anodes when necessary
Use a correctly fitted propellerwith all the washers locking bits etc properly fitted/Locitited with correct grade, correct torque where necessary. In short follow the instructions to the letter the Kiwiprop is by far the best and being lightest puts least strain on the gears/shafts etc.


Don't:
Sand it down to bare metal (yes I've seen it done!)
Use copper based anti fouling

 

[cloud7]

Had both, I think I favour sail drive as lots less prop walk due to it being farther forward, downside would be that it needs more care re anodes etc. But then I have had a shaft corrode so I think theres not much in it really.

Nearly forgot you do have to cahnge the seal on the Sail drive every 7 years so thats additional expense.

I have very little knowledge of the sail drive , would it operate like the outdrive leg on
a power boat , requiring seals , gear oil , ring anodes etc , and does this represent greater
running costs, realiability issues , against the shaft.

 

[Norman_E]

We're hoping to buy a boat with shaft drive (not that it's a criteria), but what scares me is that if the coupling fails, and the shaft falls out, we'll have a large hole in the bottom of the boat.

Better than jubilee clips, put an anode on the shaft inside the hull. The reasons are that if you have a Volvo shaft seal a jubilee clip will tear it up if the shaft moves back against it whilst still turning, and that will let water in. A jubilee clip might also pass right through the Volvo seal and the shaft tube. A shaft anode of the large diameter flat faced type rather than the steamlined lemon shaped one is best.

 

[Tranona]

I have very little knowledge of the sail drive , would it operate like the outdrive leg on
a power boat , requiring seals , gear oil , ring anodes etc , and does this represent greater
running costs, realiability issues , against the shaft.

In principle it is the same as an outdrive in that it turns the drive through 2 lots of 90degrees, but there the similarity ends. There is no steering, no bellows, no rams and all the other bits that cost on an outdrive. One anode - rings on some, but shell like clamps on the latest Volvos. High wear rate can be a problem, particularly in marinas with shorepower, but generally last between haulouts. Oil needs changing periodically as do seals in the lower leg, but neither particularly difficult. Only major service item is recommended change of the sealing diaphragm after 7 years, although opinion is divided as to the necessity. On balance no more maintenance or cost than shaft drive over time.

To be honest there are many features of a boat that are more important than what drive it has - and there are no overwhelming advantages of one over the other.

 

[noelex]

Anoter vote for shaft drive as the better sytem.

 

[Tranona]

Anoter vote for shaft drive as the better sytem.

Why? and why "another" when if you read the thread nobody has expressed a preference for shaft drive - either no preference or preference for saildrive.

 

[noelex]

Why? and why "another" when if you read the thread nobody has expressed a preference for shaft drive - either no preference or preference for saildrive.

If it makes you happy you can read it as
The first and only vote for shaft drive as the better system.
The spellings even better

I don’t want to put words in anyone’s mouth, but I used “another” because I suspected these posts represented a bias in favor of shaft drive

If you're looking for a new mass-manufacturer boat, you'll have some difficulty finding a shaft drive. I believe a few Bennies have them, but most builders opt for saildrives. I suspect economics of manufacture drive the decision, rather than more seamanlike considerations.

We're hoping to buy a boat with shaft drive (not that it's a criteria), but what scares me is that if the coupling fails, and the shaft falls out, we'll have a large hole in the bottom of the boat.

Reasons

Sail drive is a cheap way production boat builders can install an engine/prop system.
Unfortunately the cost is in added maintenance for the owner.
A sail drive is more complicated, less strong, more prone to problems, harder to fix or service without hauling the boat.
There are so many things that go into making a good yacht I would be reluctant to use this as a criteria for excluding a boat, but particularly on a bluewater yacht I would prefer shaft drive.

 

[cloud7]

Anoter vote for shaft drive as the better sytem.

In consideration of the views expressed is your preference based on experience having

had a yacht with sail drive , or just personal preference.

 

[Tranona]

If it makes you happy you can read it as
The first and only vote for shaft drive as the better system.
The spellings even better

I don’t want to put words in anyone’s mouth, but I used “another” because I suspected these posts represented a bias in favor of shaft drive
Reasons

Sail drive is a cheap way production boat builders can install an engine/prop system.
Unfortunately the cost is in added maintenance for the owner.
A sail drive is more complicated, less strong, more prone to problems, harder to fix or service without hauling the boat.
There are so many things that go into making a good yacht I would be reluctant to use this as a criteria for excluding a boat, but particularly on a bluewater yacht I would prefer shaft drive.

Somewhat odd reasoning when one of your "fors" is concerned about the security of shaft drive - misplaced as it happens because shafts don't often come out when the boat is afloat.

I don't believe it is true that there are any significant cost savings for the builder, otherwise Beneteau and Jeanneau would have abandoned them a long time ago.

One could construct just as many negatives about shaft drives as you have about saildrives. If you follow these fora closely you will see that one of the most common areas where folks have problems is with stern gear - leaky stern glands, out of alignment, cutless bearing wear, loose P brackets - none of which can be fixed without taking the boat out of the water.

There are literally 10's of thousands saildrives in use round the world - Bavaria alone have built around 30000 boats with them. On balance they are probably no more or less reliable or expensive to maintain than shaft drives over the life of the boat and do offer significant advantages in terms of refinement and space utilisation, and on many boats superior handling under power.

 

[noelex]

In consideration of the views expressed is your preference based on experience having

had a yacht with sail drive , or just personal preference.

Given my views it is not surprising I have only owed yachts with shaft drive, or in my early days yachts with an outboard as an auxiliary.
I have cruised and raced many thousands of miles in yachts with saildrive. and of more relevance, I have always tried to involve myself in maintenance of these yachts, with a view to gaining experience for cruising full time (which I am now doing)
As an owner of an aluminium yacht, with a keen interest in both electronics and mechanical problems I have been asked for my opinion on problems with saildrives (one of the nice things about cruising is people are very generous with their time to help fellow boat owners) and these earlier and more recent experiences have formed my views.
I don’t think saildrives are terrible, but I believe shaft drive is better in everything other than slightly more transmitted noise.
For the type of sailing I do I rate reliability, maintenance , ongoing cost, and strength as more important. Unfortunately the boat buying public often consider the initial purchase price as more important, hence the popularity of saildrive.

 

[noelex]

Somewhat odd reasoning when one of your "fors" is concerned about the security of shaft drive - misplaced as it happens because shafts don't often come out when the boat is afloat.

I don't believe it is true that there are any significant cost savings for the builder, otherwise Beneteau and Jeanneau would have abandoned them a long time ago.

One could construct just as many negatives about shaft drives as you have about saildrives. If you follow these fora closely you will see that one of the most common areas where folks have problems is with stern gear - leaky stern glands, out of alignment, cutless bearing wear, loose P brackets - none of which can be fixed without taking the boat out of the water.

There are literally 10's of thousands saildrives in use round the world - Bavaria alone have built around 30000 boats with them. On balance they are probably no more or less reliable or expensive to maintain than shaft drives over the life of the boat and do offer significant advantages in terms of refinement and space utilisation, and on many boats superior handling under power.

I am not sure have I became the official spokesman for shaft drive.
I have lots of friend with saildrive yachts. The main thing is to get out on the water (full time cruising if possible) and enjoy yourself.
Sometimes the debate as which constitutes the best mouse trap takes people so much effort that they want to have the perfect yacht before they will go.
The glorious sunset I observed today with a glass of red wine my wife got from a vineyard grown on the island where I am anchored and recommended by the great great grandson of the founder of the winery would have been just as good if my yacht had a saildrive
.
However I stand by my comments that shaft drive is better.

Yes there are lots of boats with saildrive.
Unfortunately the cruising life means spending some time on the hard in a boatyard. My experience has been the problems and maintaince with saildrives outweighs the shaft drive alternative.

The production boat builders know shaft drive is preferred by buyers and this can be used as a selling point, but, as the cost pressures become more intense they have tended to adopt saildrive. Beneteau have persisted with saft drive in most of there premium and more expensive First range.

 

[Bosun Higgs]

From an engineering perspective the saildrive is better - no alignment issue, smoother running, installed as a package. But two things would put me off.

The first is the idea of being dependant on a rubber membrane to keep the water out. The second is that I have had experience of alloy legs sticking into sea water and the maintenance is a real problem.

So personally I would go for shaft every time just as I would go for grp decks rather than teak every time.

 

[Quandary]

I have owned two boats with shaft drive and two saildrives ( the early ones were outboard powered), for around twenty years the boats were shaft driven but the current one is saildrive and SD would not have been my choice at the time if a shaft driven option had been available.
However, now I really enjoy not having any traces of water inside the boat, I also like the power and manouvreabilty benefits but against that, having soo much very expensive metal under the boat is a pain, as you are always vulnerable to the condition of your anodes. Inside maintenance is the same, no real difference in changing the leg oil (actually ATF) from changing gearbox oil, the engine bay is very easy to keep clean as it is like a big square shiny grp bucket which contains anything that is spilled when changing oil squirting WD 40 etc.
I still find myself nipping below when the engine has run for a while to put a turn on the greaser but catch myself on at the foot of the steps but the memory of squirming head first down through the cockpit locker into the very claustrophobic space behind the engine on a Sigma 33 to adjust the stern gland with the engine running with no real hope of getting out again without help is happily now a distant memory.

 

[Tranona]

The production boat builders know shaft drive is preferred by buyers and this can be used as a selling point, but, as the cost pressures become more intense they have tended to adopt saildrive. Beneteau have persisted with saft drive in most of there premium and more expensive First range.

That is just not true. Most of the premium builders such as HR where an extra few £'s or euros of cost (if there is any) would not be a deciding factor have moved to saildrives on sub 55hp engines because it is a better engineering solution. Beneteau and Jeanneau are in the process of introducing saildrives on their larger models (75hp) at a substantial PREMIUM of about £10k - admittedly for the rotating design.

BTW all the "cheap" Oceanis range from Beneteau still have shaft drive, as do the smaller Jeanneaus.

I do not think there is any significant consumer resistance to saildrives - rather the opposite. There are of course conservative people around who believe old technology is better and can construct arguments to support their beliefs, just as others can construct arguments in favour of newer technology, but the proof comes from the market and if there was real resistance to saildrives, builders would not fit them, wheras in fact they are gaining market share.