Saildrive or shaft on the long term

[valhalla360]

Originally Posted by lestersails

Offsetting that to my mind would be the increased hazards of gasoline on board.

Not really.

The issue with inboard gas engines is any type of fuel leak will introduce gas fumes with sink to the bottom of the hull and stay there until a vent fan sucks them out. Diesel inboards have the advantage of not producing significant fumes

With the outboard completely clear of the hull, a leak at the engine won't introduce fumes to the hull.

The tanks are bottom vented above the bridge deck, so similar to a gas powered car, a leak will dump overboard (along with any fumes).

About the only risk would be taking a big wave over the stern and swamping the motor...but in a lightweight cat running before the waves, she always sped up and the sterns would rise, so we never came close to swamping the motor.

Our insurance costs were very much in line with diesel versions of the boat. (they made a diesel version with an extra long I/O unit) We paid a fraction of the insurance price for Florida diesel boats (we were on the Great Lakes)

[d282johnson]

Sail drives are very reliable. Few things to remember, renew the gasket seal to the hull every 5 years to be safe. Make sure on the Engine service that they replace the gear oil - best done out of the water. I’ve had one for 12 years, sailed across the Atlantic - In a Hanse, no issues at all...

[PaintedKite]

Originally Posted by Golfstar

I would appreciate some advice on sail drive units.
Golfstar

Saildrives are fine. The diaphragm and clamp ring are easy to install correctly, and I've never heard of one failing. They work fine and last a long time.

Furthermore, my experience is that saildrive boats handle/steer the best in reverse BY FAR. Our Dufour 382 steers just like a car in reverse -- predictable and balanced.

The key is maintenance. Check and change the drive's oil regularly, using the same oil as your engine. EVERY TIME YOU HAUL YOUR BOAT, change the shaft seal, check/change the zinc, and make sure your housing is properly coated/painted/preserved.

[With a direct drive, you've got the shaft seal, cutlass bearing, and the shaft itself (bending) to worry about. Plenty of documented cases of those issues.]

The single biggest problem with saildrives, if you ask me, is the cost of catastrophic failure. If you get seawater into the unit and compromise the oil, you can "slick" the clutch(es), gears and seals. Rebuilding may very well exceed the cost of replacement, and replacement will approach $15K for mid-sized units.

[Cadence]

Originally Posted by PaintedKite

Saildrives are fine. The diaphragm and clamp ring are easy to install correctly, and I've never heard of one failing. They work fine and last a long time.

Furthermore, my experience is that saildrive boats handle/steer the best in reverse BY FAR. Our Dufour 382 steers just like a car in reverse -- predictable and balanced.

The key is maintenance. Check and change the drive's oil regularly, using the same oil as your engine. EVERY TIME YOU HAUL YOUR BOAT, change the shaft seal, check/change the zinc, and make sure your housing is properly coated/painted/preserved.

[With a direct drive, you've got the shaft seal, cutlass bearing, and the shaft itself (bending) to worry about. Plenty of documented cases of those issues.]

The single biggest problem with saildrives, if you ask me, is the cost of catastrophic failure. If you get seawater into the unit and compromise the oil, you can "slick" the clutch(es), gears and seals. Rebuilding may very well exceed the cost of replacement, and replacement will approach $15K for mid-sized units.

15K? I guess the manufacturers have owners by the short hairs. They are no more than OB lower unit with a flange on top. Not even with the shifting in the unit. Tell me I'm wrong.

[dmkkeng]

Originally Posted by Golfstar

Hi guys
A big thank you to all contributors. Its fantastic to get comments from so many sailers from so many countries.
I guess I opened a can of worms, but it takes your mind off covid.
I am now much wiser thanks to you all.
I'm going to buy a Hanse 430e. Hang the consequences.
Save sailing to all.
Golfstar.
Based in Spain.

There are pros and cons to both systems however at the end of the day it shouldn't be a deal breaker if everything else checks out on the boat which is likely why you made the decision you did. the Hanse 430e is a nice boat I'm envious. A couple more pros for the sail drive is less vibration and noise especially at 80% throttle, less prop walk and potentially more efficient drive system. Enjoy your new boat!

[Stockie]

Originally Posted by Golfstar

Thanks guys. Some great comments.������
So if I fork out for new sail drive seals every 5 to 7 years it should reduce the chances of sinking in an inconvenient location.
I wonder how many yachts have sunk due to leaking saildrive units. Mmm. I suppose it depends on leak rate versus bilge pump rate.
I d like hear from more experienced owners of yachts with saildrive units.
The jury is still out.
Thanks for input. ��

Hi Golfstar,

Sail drives are fine, I’ve got one in my boat, the diaphragm seal does not automatically need replacement every 7 years. If your selection of boats are 10-15 years old and up to 45 feet, the majority of offerings will have sail drives.
Mine is 14 years old and I have replaced a shaft seal, this year. There is no corrosion, but I use prop speed on the leg and prop, and a barrier of non copper AF around the hull opening.

[Dr.No]

I respectfully disagree with Post #10 that there are no GREAT boats with sail drives. The Volvo D-50 sail drive in my 2006, French built, Cigale 16 has never been a problem. With an aluminum hull, you get very concerned about possible corrosion issues. First, you need to figure out what sacrificial anodes you need, and carry spares. These anodes are quite unique, and not easily found. In my case, all anodes are Mil spec aluminum - NOT zincs. There are mathamatical formulas to figure out what additional anodes you may need, and Ted Swartz at Boatcorrosion.com is THE expert in the field. His firm deals with military and commercial marine corrosion projects. I will shortly be installing one of his Monitoring Stations. These are a very simple, bulkhead mounted, low voltage electrical meter connected to a small anode in the hull. It tells you how effective your anodes are. Cheers!

[Dalliance]

Originally Posted by Golfstar

Thanks guys. Some great comments.������
So if I fork out for new sail drive seals every 5 to 7 years it should reduce the chances of sinking in an inconvenient location.
I wonder how many yachts have sunk due to leaking saildrive units. Mmm. I suppose it depends on leak rate versus bilge pump rate.
I d like hear from more experienced owners of yachts with saildrive units.
The jury is still out.
Thanks for input. ��

Golfstar,
I have owned two cats with 4 Yanmar and 2 Volvo saildrives since 2003. My first cat was hit by a power boat the second night I owned it and jarred the 1991 Volvo port saildrive bellows enough to start a leak that was easily taken care of by a bilge pump. I’ve replaced three prop shaft seals. The 1991 Volvo had water in it since being sailed from Australia and had some corrosion on the prop shaft but was otherwise OK. I change the zince every two years but not due to wear/ erosion but it’s the correct thing to do. My first cat was struck by lightning while I was with the Navy somewhere near Japan. After the lightning strike my battery charger started leaking some amperage to ground thus speeding up saildrive corrosion. I replaced both saildrives $6,500 and owned that boat worry free for 5 more years. Very few sailors in the USA have any real saildrive experience, something that is evident while reading theses posts. I have fist hand experience with failing, stuffing boxes, cutlass bearings, engine mounts, coupling bolts..., in fact twice an emergency haul was necessary (s/v Daullphin & s/v Edelweiss). I have never had a strange rattle or noise at certain rpms due to an alignment issue with saildrives. I would not let a saildrive persuade you from picking your dream boat. Goid luck in your search.

[Rohan]

Aren't all outboard motors essentially saildrives? Do they have a major history with unreliability?



A saildrive is simply more efficient for engine power and fuel economy. The propeller thrust is forward, instead of angling up and forward.



This is just a guess, but I would bet that if you have a folding propeller, there's slightly less drag in the water also, since they are straight back instead of slightly downward and back, so a small increase in sailing speed although the difference would be very slight.

The downside is some added complication of having more moving parts. I own a traditional shaft, but would have no fears with a saildrive on a recent boat.

[Dalliance]

You are correct, in fact I gain 1 knot of speed when motoring when I leave the non-running motor Autoprop in feather (shut down the engine in forwards). Unlike outboards, the water pump is located on the engine, a bonus and my Yanmar saildrive have 2 pathways to feed the engine seawater cooling pump. I’ve had plastic bags fold over the leading edge of the drive yet the engine temp never elevated.

[motion30]

Originally Posted by Rohan

Aren't all outboard motors essentially saildrives? Do they have a major history with unreliability?



A saildrive is simply more efficient for engine power and fuel economy. The propeller thrust is forward, instead of angling up and forward.



This is just a guess, but I would bet that if you have a folding propeller, there's slightly less drag in the water also, since they are straight back instead of slightly downward and back, so a small increase in sailing speed although the difference would be very slight.

The downside is some added complication of having more moving parts. I own a traditional shaft, but would have no fears with a saildrive on a recent boat.

The lower unit of an outboard is similar to the one on the sail drive, but it is not completely immersed in the water 100% of the time. You can tilt many outboards up so they don't even touch the water. Not so on the sail drive. And the efficiency is a good point, but you do have an extra set of gears that turn the direction of power 90° and then 90° again. And generally an inboard can turn a bigger propeller. I would guess the efficiency to be close.

[valhalla360]

Originally Posted by Rohan

Aren't all outboard motors essentially saildrives? Do they have a major history with unreliability?

A saildrive is simply more efficient for engine power and fuel economy. The propeller thrust is forward, instead of angling up and forward.

This is just a guess, but I would bet that if you have a folding propeller, there's slightly less drag in the water also, since they are straight back instead of slightly downward and back, so a small increase in sailing speed although the difference would be very slight.

Some similarities but also key differences between outboard and saildrive

When the boat is in the water, the saildrive is in the corrosive salt water 24/7. Particularly bad if you are in a marina with shore power issues. That can eat up a saildrive in no time. Most outboard installations can pull the outboard completely clear of the water drastically reducing corrosion.

The propeller thrust compared to an outboard is similar except:
- Your typical outboard has only one 90degree gear change from crank shaft to prop. A typical saildrive has two increasing losses.
- A folding prop is not as efficient under power as a big fixed prop. Plus it's more expensive and requires maintenance to keep operational. With the outboard completely clear of the water, the prop doesn't grow oysters and it's the best option for sailing efficiency even with a big fixed prop (all else being equal).

The downsides to an outboard:
- At least in the USA, you can't get a diesel version. With modern 4stroke EFI, the efficiency loss is small but it is there. (On a catamaran where the outboard is clear of the hull and fuel tanks can be on the bridge deck and bottom vented the safety of gas vs diesel largely goes away).
- The boat has to be designed for outboard power. If you just bolt it to the stern, you can run into an issue where the prop comes clear of the water in steep waves. So just bolting an outboard to the stern of a boat designed for inboard power is usually a bad idea. Saildrives by their nature usually wind up well under the hull and further forward.

[moseriw]

shaft with stuffing box - notting else