Geese

sail drives, worth the hassle?

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I just did my second offshore delivery on a cruising cat. First one was a 65' with direct drives, just now a 45' with sail drives. On a direct drive, when water is rushing in its easy enough to replace the wax rope stuffing, dripless systems can often be cleaned up and put back together in the water too.. With sail drives, a seal fails and you need to haul out and/or it compromises your transmission fluid. I scrape them all the time for side money and they seem such a weak link. Trimaran Scout, which seems to be a well thought out boat is for sale right now with direct drive. Assuming you like inboards, how much do you gain in speed for the headache of sail drives? @Zonker what did you choose for your rtw? Thanks!

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I chose a conventional prop drive because of the maintenance headaches and ease of repair in out of the way places. I wasn't worried about the big diaphragm failing, but prop seals failing and corrosion seem like an common issue all the time with saildrives.  I think it was Yanmar that wanted you to change the saildrive oil every 100 hours which would be very tricky.

A builder does not have align a saildrive. Just cut a big hole, drop the integrated engine/drive mounting and glass in place. Saves tons of labour so that is why they are popular with new boat builders.

My boat also had daggerboards so wouldn't have been able to dry out on a beach - the saildrives would have been lower than the hull.

Yes, they are _slightly_ less draggy than a conventional strut and prop shaft. But only if both are fitted with similar props i.e. folding, feathering or fixed. The drag from a fixed prop is huge compared to a saildrive versus conventional.

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In terms of long use maintenance, shaft drives are light years better. Corrosion of shaft drives is an ongoing battle to prevent, along with two extra right angle gear sets As mentioned, builders LOVE them - no install technical ability needed, and less vibration. Raw water intake built in. As long as the system works for the warrantee period, they are ecstatic

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Saildrives allow for a foolproof , compact installation that keeps the engine out of the saloon, living space  . The saildives thrust is efficient.. parallel   to the waterline  and well forward of the rudder 

unfortunately they are high maintenance

on a small boat the sail drive is a winner

above 50 ft shaft drive is the best choice 

 

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...the question is more: do any serial-built boats have conventional shafts?

(I think they don't have to glass any sail-drive cradle in any more these days, the cradle is part of the grid, & the hole is probably already laminated into the hull-moulding, no need to cut one). The savings in labour must be considerable...for the owner:...not so good.

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On 11/15/2020 at 10:35 AM, slug zitski said:

Saildrives allow for a foolproof , compact installation that keeps the engine out of the saloon, living space  . The saildives thrust is efficient.. parallel   to the waterline  and well forward of the rudder 

unfortunately they are high maintenance

on a small boat the sail drive is a winner

above 50 ft shaft drive is the best choice 

 

I’ll grant you that makes good sense on a small mono. I delivered a recently built Catalina ~25’ with a single cylinder yanmar on a sail drive and when forced to motor in the ICW chop it was light years better than having the outboard bounce out of the water on the transom, it also allowed for a very spacious cabin on a 25’ boat, cheap to haul out for service (or trailer or keep on a lift). I’d argue that even a “small” cruising cat like a lagoon 38’ is a chore and expense to haul out. This 45’ cat had both sail drives serviced within the last year and <20 hours of use and  still one failed. For my own catamaran saiIing boat I think I’d consider Zonkers way and have a single inboard with a conventional shaft and an outboard for maneuvering if I didn’t have the payload and space for two inboards on this “small” cat. On a condomaran I’d just eat the lateral space and increase the freeboard. Of course I’m thinking in mortal terms, i.e. the money counts, enough where I have to do a lot of work myself.  The broker who sold the boat said that the average largish cat owner only owns their boat for 5 years before they are thoroughly worn out by the experience. This is good short-term for brokers and service yards but not for sailors. I think the owner of this condo cat has maybe one more season in him of system failures before he buys a land condo. 
people get immediate gratification from new upholstery and enclosures and even pretty sails but as a diver I can say that folks aren’t thrilled to pay too much for stuff below the waterline, racer-addicts perhaps being the exception 

anyways enough of my dribble, thanks for the feedback, I have a better idea of the incentives now. 

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None of you commenting seem to have a long term experience with saildrives yet y’all sure want to tell the world what they are like.

I’ve been living with a set of saildrives for the last eight years. These drives are from 1992 (Volvo).

I don’t agree that SD are difficult in regards maintenance issues. I check the oil when I check the engine oil. I clean them along with the bottom. The zincs are changed periodically. None of this is different than other maintenance and in fact maybe less than OB which hiccup more frequently.

I have coated my drives with Carboline industrial coating and touched that up with Interprotect. Vivid as antifoul.

 I have rebuilt the gearset, but g.zeus these things were 23yo at the time. I make sure about electrical continuity (lack thereof) from time to time.

In a few more years, I’ll think about changing the bellow/seal. How long does a shaft go before the seal packing leaks? Never, as best I can tell. (My bilges are dry btw.) I don’t give up space to engine and drive shaft arrangements, either.

I will say that there are big difference in the way Volvo (who btw invented the saildrive) and Yanmar are designed. Volvo are electrically isolated, and their clutch is better thought out, for instance. Unfortunately Volvo is suffering from the rep that Yan is distributing with their poorer SD design. (F.ex right recently with the diver pic of the eaten drive which was a yan...)

YMMV, but I think well of my drives, and just wanted to offer that up.

 

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Thanks I’ll keep the Volvo vs Yanmar distinction in mind. I’ll offer that 30 years ago many of us decided that an inboard/outboard runabout while aesthetically nicer and offering better accommodations on the transom was “not worth the hassle” (original question) on saltwater powerboats. Try to give away a 1990 I/O or sell a 1990 outboard runabout for double whatnot was worth a year ago pre COVID and I think you’ll see what I’m getting at. I’m not sure Volvo “invented” the sail drive so much as took the I/O into the sailboat arena, but again, will seek feedback from Volvo SD owners, because if they are fairly bulletproof, well, Bingo!
 

 

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6 hours ago, Geese said:

I think I’d consider Zonkers way and have a single inboard with a conventional shaft and an outboard for maneuvering if I didn’t have the payload and space for two inboards on this “small” cat.

That was (a) for weight reasons (b) for money reasons. If I had the cash, I would have tried to fit a 2nd diesel though I'd have been happy with a 2GM/18 HP.

On the other hand the Yamaha 9.9 would push the boat at almost 5 knots in calm water. The Tohatsu 6 HP, about 3.5 knots. Some HP are clearly better than others (actually the Yamaha has a particularly deep reduction ratio and big fixed pitch prop that is very efficient.

 

I have seen more than a few Volvos over the years suffer from really bad galvanic corrosion. They also had leaking shaft seals due to fishing line but that is the nature of the beast; any manufacturer would have the same issue. The Yanmar clutch issue has been quite bad for Yanmar. I'm glad Max has had so little troubles. Clearly keeping them electrically isolated is really important.

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Here’s my 39 year old Volvo sail drive after being stripped down to bare aluminum and being built up again with 6-8 coats of epoxy and a clear coat or two.

81331180-FE50-4762-88F3-E0731EBBAE2B.thumb.jpeg.0d8f4bffb788b3fe804b07bbd6a7788b.jpeg

This was done 2 years ago when the original bladder/membrane was finally replaced. The original bladder was still actually in serviceable condition when removed but glad to finally change it up. The same strip down to bare aluminum was done about ten years ago. Minor pitting had been observed at that time and monitored on the protective barrier on a seasonal basis with routine re epoxy on the top couple of layers maybe once or twice in the interim. 

Empirically, the pitting process has almost become negligible since we first stripped it and rebuilt it...in my mind the switch to plastic through hulls at that time has played a roll in reducing galvanic corrosion...that and maybe new electric boxes for shore power...can’t be certain.

The boat is in and out of fresh water 7 months a year so you can calculate the longevity as you wish. Careful monitoring of the magnesium collar and anodes on the keel is super important. They either get sanded down or switched out regularly but as mentioned, their nobility seems required a bit less these days.

One last note. The sail drive as of this season has outlasted the original 1981 engine by around ten years.

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Oh, the fresh water really, really helps. But so does a really good epoxy paint coating. Good job.

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I think this article a fair assessment if you aren’t a DIY kinda person

https://www.boats.com/reviews/all-about-saildrives/

 

FYI in my case, I am 3D owner, 1st owner had boat in charter (!), 2d used boat infrequently (incl maintenance). So the drives were only coated for the 1st time in 2013 (drives are from 1992). Boat has lived salt to brackish for its entire existence. IMO the most important thing is the electrickery. There isn’t much on this boat, so she really has never lived plugged in. I’ve gone the ‘no grounding’ route, going to marelon thruhulls etc. She sure doesn’t go through zincs quickly, I can say that much

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54 minutes ago, fstbttms said:

:lol:

 

 

 

Water cooled gearbox. Didn't PYI make a bronze saildrive for a while? I would think composite worth a try.

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The Yanmar saildrives in my Saint Francis 44 were installed in South Africa in 1991. I bought the boat in 1997 and they were suffering some galvanic pitting. I cleaned them up and put fresh zincs on, they had been wearing stock, alloy, fixed blade props, I fitted bronze Martec folding props. Three years later the boat was pulled for a massive bow to stern rebuild. The engines were totally wasted so I did a very comprehensive overhaul - bored, new pistons, cranks, one camshaft, oil and water pumps etc, etc ,etc - read they had a LOT of hours on them. I pulled the saildrives all apart and the gear trains were in good shape but the alloy housing was bad. Figuring that alloy adjacent to bronze and stainless in brine with trace electrical current is doomed I set about insulating the alloy. Although the housing legs were well pitted it seemed to me that properly prepped the would hold an (insulating) epoxy barrier coating better than freshly cast and flash painted new ones. I replaced all the seals and fitted stainless folding props. I ALWAYS isolate the engine batteries when docked, I DON'T keep the boat on a marina and the zincs last three years, the legs look like new and the drives have run faultlessly. The precision drive train is way less maintenance and vibrates less than any of the shaft drive installations I have been involved with and with the folding props they are low drag for my SAILING catamaran that I like to SAIL!

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anything going wrong with the shaft seals on a SD - bad news, particularly if you are "out there doing it" (like Chagos,Red Sea,...) where you can't haul. Never had water entry (only 2 years experience with SD), but lots of people have...

if the corresponding thing went wrong with our shaft drive (previous boat, 10 years, 2 rtw) this meant either putting  up with a dripping stuffing box or changing  the Volvo-"stuffingbox" in the water (no big  thing,  did  it  once).

& I am not yet  talking about the major hassle of replacing  the big  diaphragm (mandatory every 7 years).

anything wrong with your gearbox: SD - haulout

While our Volvo D2-40 with SD did not give us any  trouble in 2 years (France-Tahiti) - it sure was on my  mind...particularly  the "water in the gearbox-ooil thing", as time & again we talked to people afflicted...

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I had a collision with an UFO at 19 knt 300nm east of Beaufort,NC,Oct.2019.It hit the saildrive,destroyed the flange and the gasket.Took 3/4 of the rudder as well.Being on a trimaran it was not dramatic.Sailed back to Beaufort & fixed it.Put a skeg in front of the saildrive.

5C8A14DE-3C98-4DF6-B276-C52D36E232BC.jpeg

271C4129-5731-422E-8E8F-0550071F5AEA.jpeg

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Shaft drive has less drag if done correctly so I was told by a high profile designer but not sure how much.

Much easier to install sail drive.

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On 12/2/2020 at 2:28 AM, CPM said:

I had a collision with an UFO at 19 knt 300nm east of Beaufort,NC,Oct.2019.It hit the saildrive,destroyed the flange and the gasket.Took 3/4 of the rudder as well.Being on a trimaran it was not dramatic.Sailed back to Beaufort & fixed it.Put a skeg in front of the saildrive.

 

I had a Volvo MD11c W/ Sail Drive on a 40' mono hull. We were trying to get out of the Strait Of Juan De Fuca before dark and were motor sailing at around 8-9 knots in somewhat rough conditions;   when we struck a 40' log that pivoted between the keel and sail drive as it smashed into the boat on port and came out on starboard. It was dramatic. The boat was an ex-OSTAR boat and very stout. The sail drive and the diaphragm held but we bent the gear shaft in the sail drive and striped the feathering blades off the hub. Surprisingly it caused some engine damage too. I was very impressed with the durability and strength of the underwater portion of the sail drive.. If we had the type of damage you show in your pictures.... we would have sunk fast.

 

Edited by 2flit
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