Sail Drive Engines

[tonycooper]

Thanks for comments before, very helpful! We are getting there, we have seen a lot of boats that may be suitable. However, I would just like to ask peoples views on saildrive engines; any comments/advice would be much appreciated.

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[tony_brighton]

Its generally acknowledged that builders fit saildrives cos they are cheap to install (usually early in the build phase). You'll find them on most modern boats these days and pretty much all of the builders will be installing them.

PROS
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-the alignment problems associated with shaft drivs are avoided.
- easy day to day maintenance (no need to pack a stern gland for example)
- they take up less space
- cheaper
- no prop wash to speak of; the prop is deeper in the water
- they dont leak (see CONS)

CONS
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- every 8 years or so the manufacturers recommend replacing the seal around the drive (a fairly large job) to avoid it leaking. There's been lots of info on this point - best do a search here.
- to replace the gear box oil you have to be out of the water as the drain plug is on the bottom of the leg.
- no prop wash (if you need to use it)

My summary would be that SailDrives are not problematic - just be aware of the characteristics.

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[extravert]

And another con

The saildrive legs are usually aluminum alloy. Having a big lump of bronze attached to a lump of aluminum, then all permanently immersed in seawater, can cause corrosion problems. If the leg corrodes beyond salvage, replacement of just the leg can be so expensive that the whole engine is not economic to repair.

<hr width=100% size=1>One day, I want to be a real sailor. In the mean time I'll just keep trying.

 

[Ric]

Tony Brighton gave an excellent summary of the pros and cons. All I can add is that I occasionally meet sailors who wish they had bought a boat without saildrive, but I have never yet met one who wished he had it.

One other con not mentioned is that you can't run a propshaft alternator off one. They are very nice things to have on a cruising boat.

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[Rohorn]

Hi.....so far no one mentions noise. My two Yanmar saildrives (1GM10/SD20s) were extraordinarily quiet. Much of this goes to the very supple engine mounts and all-of-a-piece construction. No long rumbling shafts.
My paranoid worry was that the double diaphragm through-hull seal would fatigue and split because of the mount flexibility and movement. Not a bit of it. I had them apart and those seals were as good as new after 14 seasons. Some years ago, I asked Peter at Marine Power about the "mandatory" replacement of the seals, apparently demanded by insurance companies. He was scornful.."they cost a lot and it's simply not necessary...not Yanmars anyway".
I'm re-engining with 2GM20/sd20s with some confidence, accepting the water-pump impeller change difficulty, not having time to wait for the new YM motors which have that problem tied up too.
Cheers....R

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