Sail Drives, The Good, The Bad and Ugly

[Rich T]

Would like to hear First Hand experience with Volvo, and Yanmar (or other) sail drives from those who have been using them for awhile. Specifically corrosion resistance, durability of drive, durability of hull seals and ease of replacement. Any chronic problems? I haven't found any body in my area that has owned them for more than a season or two, don't really believe the dealers are telling me the whole story.....sounds too good to be true.

[tamicatana]

Six months and so far I'm ok with mine. Just have to maintain 'em, they're not things you can just ignore

ps: search for my threads, I have mentioned somewhere here how I found that you can get water incursion into the oil not only from the prop shaft seals but from the flange gasket between upper and lower unit. Again, maintenance.

[svrevelations]

Our Yanmar saildrives have been in the water for almost 6 years - although we have only done 250 hours over this time period. To date, weve had no problems and are quite happy.

[Rapanui]

Our first set of 2 Yanmar 2GM20 18HP saildrives lasted 5500 hours and were in good condition when we re-engined with 3YM30s.

The only issue was and is seawater ingress into the saildrive oil towards the end of the season (bearing in mind these engines do up to 1000 hours/year) which our charter company managed by regularly changing the oil. This did not cause any other problems with the units.

They have now been advised by Yanmar that this problem was caused by the oil level being set too high on the dipstick and have now recommended running the units at the minimum level. We will see if that works!

[Rapanui]

Should have said, the charter company change the saildrive prop shaft seals every year along with anodes.
Yanmar hull seals are double with a sensor in between which alarms if there is water. I have not heard of one failing.
No issues with corrosion in 6 years in water.

[cruiz9]

Had 2 saildrives fail on my cat after only 800hrs and Yanmar Australia would not cover them because they where a few months out of warranty,cost to replace 19k.
Fortunatley my insurance company at the time where happy? to cover the cost {nautilus Ins } .Yanmar make great motors but crap saildrives,prone to to many failures even when you stck to the servicing schedual to a T,

[Talbot]

Yanmar up to 30hp use an SD20 saildrive - biggest problem I have come across is the valve on the leg used for an inlet for cooling water">engine cooling water. Best to isolate and use a proper thruhull. Ambassador are the only stripper that fits, and it needs to be modified if you are using autorprops.

Autoprops for a saildrive have to be rubber mounted, and thus need an (expensive) service every 6 years.

Numerous reports of problems with the SD50 concerning the cone clutch.

[Cotemar]

I have two Volvo Penta D1-30F engines with Volvo Penta MS 130S-B sail drives with VP folding props.
They have worked great for the five years that I have had them. I just change zincs and oil.

[DotDun]

Yanmar SD20s, 2200 hours and 10 years with no problems. Change oil and lower seals at every haul out.

No corrosion problems, not electrically connected to shorepower (isolation transformer).

[colemj]

Volvo saildrives 15yr old 2500hrs never a problem. I changed the shaft seals for the first time at 10yr old and the seals looked like new. I may change them again just for fun after 6yrs.

The Yanmar drives larger than the SD20 use cone clutches that have been a disaster for Yanmar. They now recommend removing and lapping them every 400hrs or so. Volvo drives do not have this problem, nor does the SD20, which uses a dog clutch. The newest Volvo drives use clutch plate packs that had reliability problems in the early releases. That problem has been solved now.

The new Volvo drives allow oil changing without haulout and a split zinc that allows changing without prop removal. Don't know about the new Yanmars.

The Volvo drives are electrically isolated from the engine, which helps shield them from galvanic corrosion. Again, don't know about the Yanmar, but I don't think it is isolated. Corrosion should not be an issue - if it is, there is something wrong with your boat, the boat next to you, or the wiring, and it needs immediate addressing.

I have never seen or heard of a hull seal failure on either manufacturer, other than by hitting something that punches the drive into the hull, or otherwise puts unusual force on the leg itself. Volvo recommends replacing this seal every 7yrs and Yanmar recommends every 2yrs (I think). Ours is 15yr old and still looks and feels like new.

Both brands would be equally easy/difficult to replace if necessary, but don't see why you are contemplating replacement.

Mark

[fstbttms]

Yanmar & Volvo saildrive legs both have 2-piece zincs that can replaced without pulling the prop. Other saildrives do not.

[hugosalt]

Below is copied from my post from earlier in the year...

Have Yanmar SD20 with folding prop on my 30" sloop, saildrive is 27 years old. No leaks, original seals...wanted to change seals
several times just because, yanmar dealer says not needed and
cited older units still going strong with original seals.
Am coastal sailor and would change seals if going offshore or if
did not know history of older unit.
Have gone bump in the night few times, one time sailing over a
substantial submerged tree with no problem. Saildrive sits somewhat protected behind keel, would rethink if more exposed
as could be on a catamaran.
Makes for very quiet motoring with no vibrations transfered to hull and bilge is dry as no shaft seal leakage and no critical shaft line up. My install my be somewhat unique as motor is turned 180 degree from normal install and presents easy access for inspection of saildrive seals and gear oil.
Almost forgot, there are actually two robust watertight seals
that have a sensor between them that sounds an alarm if
any water ingress. Alarm has never sounded other than when I
remove and test. There is a 3rd exterior seal/rubber flap not
water tight on the bottom of the hull/ saildrive leg that keeps
out growth.
One has to be careful about keeping raw water intake open and I have installed a 3 way valve to another thru hull if needed, i don't need to use but am very careful about keeping bottom/saildrive clean.
All in all am happy with yanmar sd20 saildrive, which are still made today...can not speak to Volvo drives...and certainly aware that many are not fans of saildrives.

Will add that boat lives on a mooring, far away from marinas
with shore power.

[ggray]

13 yr Yanmar SD20. 1900 hrs.Have replaced the shaft seals 2 times.

I think a likely cause of water intrusion is the lack of a vent on the saildrive gearbox. Lot of pressure differntial. I installed a header tank connected to the fill cap, located 1 ft above the waterline. This keeps a slight positive pressure inside the SD, so should be better than venting. The seals last longer, and it is easier to check/top off the oil level.

Be particular with o ring on drain plug.

I also use a galvanic isolator. Plently of zinc left at each 2 yr haulout.

Never had shaft drives, so can't compare.

[DRS]

Volvo sail drives 13 years old. I've been the owner for the past 4 Just changed the lower prop shaft seals this year.(they may have been done at some point by the PO I don't know) 4100 hours on the engines. Would do it again without hesitation. Change the zincs annually.

[Lagoon4us]

Volvo SD2 55HP drives, port side one picked up 100metres plus of very heavy fishing line that was amongst a floating trashfield just south of HVAR and chopped our seals out in a heartbeat, this occurred at 3am and resulted in total loss of oil and damaged the bearings before a overheating alarm sounded.

Rebuilt the box with new bearings and seals/clutch pack and converted both drives over to mineral engine oil instead of ATF, both legs are humming along nicely the drive never slips and gear change is crisp and certain. Gear oil remains golden in colour.

Volvo are good but as with all things that float EXPENSIVE!

Cheers Frank