What are the pro's & con's ....

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BoatlessinOslo

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What are the pro\'s & con\'s ....

Hi all,

I'm a relative newbie to sailing and I would like the benefit of your experience concerning the pro's & con's of saildrive vs shaft drive.

JK

Why's that smoke coming out the hatch ?<P ID="edit"><FONT SIZE=-1>Edited by BoatlessinOslo on 30/09/2002 13:05 (server time).</FONT></P>
 
Re: What are the pro\'s & con\'s ....

Saildrive

PRO
-Engine can be installed further forward= better centre of gravity

CON
-Seal needs to be replaced every 5 years. Shaft seals need maintenance as well, but are less a pain in the *ss.

- Propeller is usualy further from rudder, so increased prop walk in forward gear. My prop (with shaft) is directly in front of the rudder, so if I apply throtle, the wash goes over the rudder immidiately= good control at slow speed. But this is not necesarily a shaft vs saildrive issue. It's more of a boat design issue.

- hole in boat is bigger, so if/when things go wrong...

Group of people on the pontoon: skipper is the one with the toolbox.
http://sirocco31.tripod.com
 
Re: What are the pro\'s & con\'s ....

I've heard it said (that is, I've never seen it myself) that some boats which are engineered for production line efficiency build furnture around the engine/saildrive unit in a way which makes subsequent work on the unit difficult without extensive surgery on the boat interior, even for routine tasks like replacing the seal.

Worth bearing in mind when you look for a boat.
 
Re: What are the pro\'s & con\'s ....

Saildrive seals need to be replaced every 7 years, not 5. Though there has been no reported incidents from leaving it longer.

Another SD con, certainly for the Volvo, is that the seacock feeds through the saildrive, and therefore is difficult to get to. On a shaft drive the seacock can be located at the front of the engine bay.

Also, there is only one rope stripper for SD's and they are very expensive.

<font color=blue>Jeremy Flynn/forums/images/icons/crazy.gif
Dawn Chorus</font color=blue>
 
Re: What are the pro\'s & con\'s ....

Now i am no expert but i have just spen the past few days communig with stinkies
See my post on the mbc site
Various discusions i listened seem to come to a consensus that shafts can be easier to predict than sterns when close quarter manoeuvering. They also said steerage disappears more quickly than shafts at slow speed.
The other thing was that when shafts get older they need much more tlc than saildrives.

I could be talking bollocks but that is what my ignorant enquiries taught me

oh and finally everyone said bow thrusters are a must.



Beer! Now there's a temporary solution.
 
Re: What are the pro\'s & con\'s ....

Things I've found...

- Less (ie none on mine) stern kick in reverse. This is because the prop to hull gap is larger, and the prop is nearer the centre of the boat so less leverage.

- Gasket replacement period and water inlet position vary with manufacturer. Info stated so far is probably for Volvo. Bukh are different. Engine out job to replace gasket.

- the leg is often aluminum, in close proximity to a bronze prop. Corrosion waiting to happen, despite anodes.

- horribly expensive to repair when things go wrong. If the leg needs replacing on an old engine, the engine may be uneconomic to repair.
 
Re: What are the pro\'s & con\'s ....

I am interested in your statement that shaft need more tlc when they get older. What is the basis of this.

One thing against shafts is that they bend when you get the halyards or sheets round them (personal experience). Then they have to be replaced

Chris Stannard
 
Re: What are the pro\'s & con\'s ....

Thanks to all for your replies and from them it seems that saildrives are an invention of the engine and/or boat manufacters to make sailing more expensive and problematical than necessary (or have I missed something?)

Why's that smoke coming out the hatch ?
 
Re: What are the pro\'s & con\'s ....

I dont know for certain but I would suspect that there was more power loss in a SD leg than the more direct drive of a shaft.
 
Re: What are the pro\'s & con\'s ....

A marine engineer advised me that saildrive can have problems with the water intake. Since the water inlet and plumbing is in the leg itself - you have probems.

1 - If the intake gets blocked.
2 - When the leg gets older and the pipes in the leg start to get corrosion buildups.

His advice was to fit a separate water intake. Then you can always pull the pipe off - and poke out the obstruction.

John M
 
Re: What are the pro\'s & con\'s ....

This was speaking to a guy who chartered various boats mainly fairlines and sunseekers

He said that the long in the tooth shaft drives tended to need more watching and when they went they went big. It all depends on your definition of old. We chartered a 2 yr old targa 37 with 5000 engine hours. hence he kept none of his boats beyond 3 yrs after which the servicing costs ate into his profits too much.

sorry for delayed response have been off line

Beer! Now there's a temporary solution.
 
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