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Old 13-07-2013, 12:56   #16
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Re: Direct drive as opposed to skeg leg

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Originally Posted by perchance View Post
True enough but they are a lot more involved as regards setting gear lash and rolling torque in comparison with hydraulic or gear transmissions.
OK, you are stretching to make your point. The gear lash is set by shims. If you don't throw the shims away when working on it, then you will not have problem with gear lash when you put it back together. If you do throw them away, you will need to measure the shim thickness needed and order new ones.

I suspect that if one is tearing into their transmission to this extent, then one understands gear lash and doesn't throw parts away as they remove them.

But yes, when ripping apart and putting together a transmission, gear lash is more important for saildrives than most shaft drives. As is problems with throwing away random parts. You got me there - major problem with saildrives...

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Old 13-07-2013, 13:09   #17
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Re: Direct drive as opposed to skeg leg

Mark,

briefly, I believe you misunderstood me. I do not "hate" saildrives. It is true that I have a number of friends with them, and I do pay attention to their travails. I was not really thinking about the catamaran incident; I think that kind of problem rare, and as mentioned above, if that one had had a water-tight bulkhead, it would not have been in danger of sinking.

However, I have reached the conclusion that owning a saildrive may have hidden difficulties that a naive buyer might not be aware of; also that there can be hidden expenses to having them that such a person would like to heard of.

Sorry, can't continue now.

Ann
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Old 13-07-2013, 13:33   #18
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Re: Direct drive as opposed to skeg leg

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Originally Posted by Ann T. Cate View Post
Mark,

briefly, I believe you misunderstood me. I do not "hate" saildrives. It is true that I have a number of friends with them, and I do pay attention to their travails. I was not really thinking about the catamaran incident; I think that kind of problem rare, and as mentioned above, if that one had had a water-tight bulkhead, it would not have been in danger of sinking.

However, I have reached the conclusion that owning a saildrive may have hidden difficulties that a naive buyer might not be aware of; also that there can be hidden expenses to having them that such a person would like to heard of.

Sorry, can't continue now.

Ann
Speaking from direct personal experience of having two 15yr old saildrives, we have not had any hidden expenses or difficulties with them. I know very many boats with saildrives with experiences similar to ours.

The expenses and difficulties are as follows:
1. The oil should be changed every 200-400hrs of use. This is every 2 years for us. Most drives use a gallon of regular engine oil, so costs are <$20.
2. Older units require haulouts to change the oil, although 75% of it can be changed without haulout.
3. They require non-copper paint, although they can be painted with copper paint if epoxy coated. A quart of non-copper paint will last for 4-6 years and costs <$40.
4. They require zincs to be changed whenever they get used up. Ours are ~25% gone after 2 years, but we change them on haulout anyway. Zincs cost <$20
5. If the shaft seals leak, they need to be replaced, and that requires a haulout. Shaft seals are simple lip seals and 2 of them cost <$20. They are easy to replace and many people just replace them as a matter of maintenance whenever they haul.

So every two years when we haul to paint the bottom, I replace the oil and zinc and paint the drive. Let's just pretend I also change the shaft seals. Total cost of maintenance is <$50 per drive.

I have no doubt that failures are expensive. They are that way for all transmissions, and may be more for saildrives.

The question becomes do saildrives fail often. My experience is they do not. However, on these threads, personal experience and provided data usually play a backseat role to the "conclusions" reached by those with no personal experience.

So please go right on telling the OP about all the hidden costs and difficulties you have concluded exist from your non-experiences. I am sure he appreciates it.

I confused your Buhk example for the Seawind example, but the premise is the same - an unusual event caused a problem and your suggestion that one prices haulout facilities before cruising just because one owns a saildrive is still plain silly and non rational.

I am more sympathetic to the Seawind example because it could be difficult to know a lone rock is present in opaque water. I am must less sympathetic to the Buhk example because wiring should be checked regardless of what type of transmission or boat one has. Bad wiring is going to cause expensive problem on all boats, and could cause an aluminum boat to sink (which is worse than a saildrive). Not to mention electrocute someone.

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Old 13-07-2013, 13:33   #19
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Re: Direct drive as opposed to skeg leg

I agree with most of the other posters that shaft drive is superior to sail drive on a crusing boat.
The mechanical problems are less, the corrosion problems are less, and shaft drive seem to survive collision with debris much better.

I would not rule out sail drive in any boat I was looking at, but it would be a negative.
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Old 13-07-2013, 13:41   #20
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Re: Direct drive as opposed to skeg leg

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Originally Posted by noelex 77 View Post
I agree with most of the other posters that shaft drive is superior to sail drive on a crusing boat.
The mechanical problems are less, the corrosion problems are less, and shaft drive seem to survive collision with debris much better.

I would not rule out sail drive in any boat I was looking at, but it would be a negative.
The OP asked about them in regards to a racing boat, not cruising.

You can't just say stuff in a definitive voice and make it true.

I have zero corrosion on two of our drives, and know of many, many others without corrosion. I will grant that because the lower leg is aluminum that corrosion must be kept in mind more. That is also true for aluminum boats, so why do you sail one?

Search this forum and you will find equal number of mechanical problems with both transmission types. Almost all of the saildrive problems will be with a single manufacturer/model and related to the cone clutch.

Walking haul out yards, I rarely see problems, so your statements seem more along the line of "you can double your chances of winning the lottery by buying two tickets". In other words, if your statements are true at all, they are meaningless in practice.

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Old 13-07-2013, 14:30   #21
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Re: Direct drive as opposed to skeg leg

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Originally Posted by colemj View Post
The OP asked about them in regards to a racing boat, not cruising.
Saildrives are more suited to a racing boat and if this was the application then my apologies. A sail drive is generally the best option and the OP should disregard my comments, but my reading of the OP is that he is looking at a cruising boat
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Originally Posted by Oceanride007 View Post
One of the vessels I am considering getting for a Blue Water cruise has a skeg drive, honestly its not my preference as I’m more familiar with straight drive. .
Quote:
Originally Posted by colemj View Post
Walking haul out yards, I rarely see problems, so your statements seem more along the line of "you can double your chances of winning the lottery by buying two tickets". In other words, if your statements are true at all, they are meaningless in practice.
I talk to a lot of cruising sailors and problems with sail drives are not rare.
Even routine membrane replacement on a saildrive is a cause of major headaches in countries where the standards of mechanical repair are dubious. Many amateurs feel this job is beyond their skill level.
Quote:
Originally Posted by colemj View Post
I will grant that because the lower leg is aluminum that corrosion must be kept in mind more. That is also true for aluminum boats, so why do you sail one?
Electrolytic corrosion is very dependent on the amount of material in the anode. If a problem develops the small amount of aluminium in a sail drive leg (15Kg?) can suffer rapid corrosion. The much larger amount of aluminium in a hull (4 Tonnes ?) will suffer much less of a problem.
Sail drive legs are also usually built of less corrosion resistant aluminium. than boat hulls.
There are also difficulties with antifouling. Aluminium hulls require specific antifouling pains while these are also used on sail drive legs the rest of hull on a fibreglass boat is likely to coated with coated with copper based paint. With the correct procedures there are no problems, but there is the potential to create a large battery with very rapid corrosion.

Most things on boats involve compromise, but the rugged simplicity of shaft drive is superior for a cruising boat IMHO.
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Old 13-07-2013, 14:53   #22
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Re: Direct drive as opposed to skeg leg

Quote:
Originally Posted by noelex 77 View Post
Saildrives are more suited to a racing boat and if this was the application then my apologies. A sail drive is generally the best option and the OP should disregard my comments, but my reading of the OP is that he is looking at a cruising boat


I talk to a lot of cruising sailors and problems with sail drives are not rare.
Even routine membrane replacement on a saildrive is a cause of major headaches in countries where the standards of mechanical repair are dubious. Many amateurs feel this job is beyond their skill level.

Electrolytic corrosion is very dependent on the amount of material in the anode. If a problem develops the small amount of aluminium in a sail drive leg (15Kg?) can suffer rapid corrosion. The much larger amount of aluminium in a hull (4 Tonnes ?) will suffer much less of a problem.
Sail drive legs are also usually built of less corrosion resistant aluminium. than boat hulls.
There are also difficulties with antifouling. Aluminium hulls require specific antifouling pains while these are also used on sail drive legs the rest of hull on a fibreglass boat is likely to coated with coated with copper based paint. With the correct procedures there are no problems, but there is the potential to create a large battery with very rapid corrosion.

Most things on boats involve compromise, but the rugged simplicity of shaft drive is superior for a cruising boat IMHO.
Maybe he is talking about a cruising boat. He does mention that, then his last sentence asks about racing boats. So he will need to clarify.

Funny, I have seen more electrolysis-damaged aluminum boats than saildrives. Of the three aluminum boats on the hard during our last haul out, every one of them were cutting out and welding large areas of corroded plates and keels. 10 boats were in the yard with uncorroded saildrives (btw, these were 10 cats, so 20 saildrives).

Copper paint on fiberglass hulls will not set up a battery with the aluminum saildrive. The only potential problem is with copper paint being used directly on a bare aluminum drive, but even that will take a long time to set in.

I bet the aluminum grades used on saildrives are the same as for aluminum hulls. If not better.

Saildrives have proportionally more zinc anode protection than aluminum hulls to make up for the material.

Routine membrane replacement is grasping at straws for an argument point. Yes, Volvo recommends replacing it every 7 years, but I know of very few people who do. Ours are 15yr old and look like new. I know of no membrane failures, other than those where catastrophic events punched the drives through the hull or twisted the engines off the mounts.

Even if one wanted to replace, the skill level necessary is very low - unbolt the leg from the engine, unbolt the membrane flange, lift the leg out, remove the membrane, clean the area, slide the new membrane on, rebolt the flange, rebolt the leg to the engine. The whole thing requires 2 socket wrenches and sufficient understanding of "lefty loosy, righty tighty".

I am amazed at how many "facts" appear on forums from people who have no personal experience and never bother to check what they "know". I apologize in advance if you have experience replacing saildrive membranes, but your understanding leads me to believe you do not.

As for rugged simplicity of shaft drives, the number of threads here relating problems with them suggests otherwise. Alignments, stuffing boxes, mounts, corrosion, transmissions - lots of problems there also.

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Old 13-07-2013, 15:09   #23
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Re: Direct drive as opposed to skeg leg

colemj, I have been messing around with boats for a long time. When I was the general manager of Kettenburg Marine, in San Diego, a long time ago, we were VERY happy to see sail drive vessels in the yard. It was a guarantee of a prosperous haulout and repair, because, unlike yourself, MOST other owners were not conscious of the potential for damage, and totally ignorant of the consequences once damage had begun. If I were in the market for a boat, I would steer a wide course away from this particular piece of propulsion, unless I had beaucoup resources to fund the repairs.
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Old 13-07-2013, 15:10   #24
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Re: Direct drive as opposed to skeg leg

I did not mean to imply that saildrives were in any way inferior or less robust than traditional marine transmissions. There is however an additional expense to owning a saildrive in that it takes longer to remove and re install plus the fact that it will probably take a skilled technician upwards of six hours of bench work to rebuild. Even changing propshaft seals calls for hauling the boat.
Labour rates being what they are I can see this adding up in short order.
For what it's worth, Mercury Marine does not recommend painting antifoul within two inches of the aluminium transom mount
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Old 13-07-2013, 15:18   #25
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Re: Direct drive as opposed to skeg leg

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Originally Posted by Roy M View Post
MOST other owners were not conscious of the potential for damage, and totally ignorant of the consequences once damage had begun.
How is this a problem with saildrives? I can name LOTS of equipment and construction techniques (and boat owners) that fit that description. Owners unable to follow clearly outlined instructions in the owners manual does not make the equipment faulty.

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Old 13-07-2013, 15:19   #26
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Re: Direct drive as opposed to skeg leg

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Originally Posted by perchance View Post
For what it's worth, Mercury Marine does not recommend painting antifoul within two inches of the aluminium transom mount
For good reason, too. Saildrive installs have a natural 3-4" gap, so getting antifouling close isn't much of an issue.

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Old 13-07-2013, 15:20   #27
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Re: Direct drive as opposed to skeg leg

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Originally Posted by colemj View Post
For good reason, too. Saildrive installs have a natural 3-4" gap, so getting antifouling close isn't much of an issue.

Mark
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Old 14-07-2013, 12:10   #28
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Re: Direct drive as opposed to skeg leg

To the OP:

You mentioned in your first post to the effect that you were looking for a boat for a blue water cruise. Now, I'm wondering whether this would be a short term deal, or something where if you take to it, it could be longer term?

You might be interested to know that Kettenberg Marine in San Diego was the largest, and most respected yard in SD for many years. Therefore, I would weight Roy M's statement that they loved to see saildrive vessels come in because they knew it would be lucrative. I suspect that's the "real Mc Coy."

The problems I have written above are not of my own experience, but that of close friends. I do try to learn from their experiences. Makes my life easier.

A month on the hard for lay days due to slow tradesmen can happen, and it will cost in the neighborhood of $100.00/day. That is why our friend's "plug" saves him money: he can be relaunched and moved to a mooring. The leg that fizzed was the second one he had on the boat.

All grist for the mill, isn't it?

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Old 14-07-2013, 12:22   #29
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Re: Direct drive as opposed to skeg leg

Mark, you keep harping about folks who don't themselves own a saildrive making negative comments about them.

One of the nice things about being an observant and intelligent human being is learning from the experiences of others. I have, over a lot of years of active cruising, observed other boat owners suffering from problems with their saildrives. Some of these boat owners have been close personal friends whose boat issues were well known to me and often discussed at length. Others have been simple observations of strangers' boats.

It is the sum of these observations that has formed my decision to not buy a boat equipped with a saildrive... thus ruling me out of being able, in your terms, to add anything useful to this thread. You, and all the other readers, are welcome to disregard my thoughts for whatever reasons you may have. But to say that they should be disregarded simply because I do not own a saildrive seems unjustified.

I hope that you continue to have good usage of your saildrives, and that the OP, should he eventually buy a boat with one (or two) has an equally good experience.

Cheers,

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Old 15-07-2013, 03:40   #30
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Re: Direct drive as opposed to skeg leg

I'm the OP, whatever that is.(I'm new), sorry about incorrect name (skegdrive instead of saildrive).

My original question was prompted when I saw 2 of 2nd Hand boats of the same manufacturer with both kinds of drive, I would put them into Bluewater category as they are pretty tough but I did ponder if I was missing out on something that may have influenced the Manufacture.
Now, I’ll take a punt and guess that the saildrive sail boat was home finished and chosen so that installation was less of a hassle as no alignment issue and general advantage of a package / speedy completion and possible fashion at the time cos that’s what all the fast boats did..

What I already new but confirmed by this thread the following, re saildrive, I believe if you follow manufacturers recommendation anode/seal/oilchange/electric isolation/inspection they will be reliable.
If you have a hull shape that suggests there use, then go for it.

Personally
I have a vague memory of an owner that had to replace the Engine/saildrive combo as a particular kind of sail drive was aged and no longer available. That saildrive failed due to fouling a spinnaker sheet.

I have known a propshafts to separate from the coupling and disappear out the back, leaving a big hole, the sterntube.

But I do prefer simplicity, reduced reoccurring expense and regular inspections to avoid surprises.

I like opinions, users experiences, prejudices. I’ve learnt much from this thread as intended. Like you, I may not be right, but I’m never wrong.

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