Converting from shaft drive to sail drive - Questions

[skybolter]

I was very curious about the sail drive as well... do they have more drag than the traditional shaft drive system?

[Steve DAntonio]

Originally Posted by chowdan

Hey all,

I am not looking to do this right now - I just wanted a video of a popular youtube channel where they converted from shaft to saildrive in an effect to get their electric system more efficient and this got me thinking.

As some of you know I am a full time live aboard, working on rebuilding/setting up for cruising while saving up and awaiting for my now hopeful stock option pay out in 2 years before I head out cruising. Goal is to cruise from PNW down the coast to Baja, do a bit of cruising in Sea of Cortez then make the jump over to the south pacific and from there who knows.

That being said, our boat is a fairly heavy boat - 42ft and last haul out prior to moving aboard and being loaded was weighing in @ 36,000 lbs. In reverse she has really terrible prop walk to starboard - we have to goose it out of the slip for the first 30 feet or so before the rudder kicks in.

The other thing is that our engine is using a V drive transmission. The shaft comes in through the boat right under the engine and as such, visually we can not see our shaft or shaft seal - major concern of mine since you can't monitor its state.

That being said, after watching their conversion video I started thinking about it. THe biggest pro for me IMO would be the fact that the engine can be rotated to face forward and that the shaft doesn't live under the engine where i can't inspect it.

Does anyone have any opinions on this conversion? Has anyone personally done it? What was the experience like?

PROS:
- Engine can face forward - no longer have to climb through small access holes to just work on something like the alternator
- No longer have the worry about alignment issues
- Shaft seal is removed(though replaced with something else)
- Sail drive is inspectable
- Future wise can upgrade to all electric and gain regen
- Engine MAY be able to move aft - giving more working room
- Prop walk reduced or gone

CONS:
- PITA to service in far away locations
- Requires haulout for oil changes
- Stray current causes corrosion
- Obviously things I am not thinking of


PS my engine is a Yanmar 4JH2-UTE - 100hp turbo.

One more con, huge hole in the bottom of the boat, whose watertight integrity now relies on a rubber boot...

[DeValency]

Sailing Uma did that (and this is a real power couple brilliant sailors-architects!) as they got a deal for a new electric engine, replacing their former electric.
I’m dreaming of replacing my Volvo Penta TMD31B 100HP with an electrical propulsion and will do it one day but definitely keeping my shaft drive - luckily it is a standard setup and the prop ends close to the huge rudder skag.

I can definitely agree with your idea of going to a sail drive setup. A V drive was a stupid idea to start with, especially with monohauls. However, the cost of doing it, in your boat may be extremely high. If you have aft berths/center cockpit with an aft master cabin it would probably be impossible- let alone the (prohibitive) costs involved.

Have you considered a folding prop? Some designs (FlexProp) can help a lot with a brutal prop walk.

Otherwise, replacing the boat could be a more practical solution...

Originally Posted by chowdan

Hey all,

I am not looking to do this right now - I just wanted a video of a popular youtube channel where they converted from shaft to saildrive in an effect to get their electric system more efficient and this got me thinking.

As some of you know I am a full time live aboard, working on rebuilding/setting up for cruising while saving up and awaiting for my now hopeful stock option pay out in 2 years before I head out cruising. Goal is to cruise from PNW down the coast to Baja, do a bit of cruising in Sea of Cortez then make the jump over to the south pacific and from there who knows.

That being said, our boat is a fairly heavy boat - 42ft and last haul out prior to moving aboard and being loaded was weighing in @ 36,000 lbs. In reverse she has really terrible prop walk to starboard - we have to goose it out of the slip for the first 30 feet or so before the rudder kicks in.

The other thing is that our engine is using a V drive transmission. The shaft comes in through the boat right under the engine and as such, visually we can not see our shaft or shaft seal - major concern of mine since you can't monitor its state.

That being said, after watching their conversion video I started thinking about it. THe biggest pro for me IMO would be the fact that the engine can be rotated to face forward and that the shaft doesn't live under the engine where i can't inspect it.

Does anyone have any opinions on this conversion? Has anyone personally done it? What was the experience like?

PROS:
- Engine can face forward - no longer have to climb through small access holes to just work on something like the alternator
- No longer have the worry about alignment issues
- Shaft seal is removed(though replaced with something else)
- Sail drive is inspectable
- Future wise can upgrade to all electric and gain regen
- Engine MAY be able to move aft - giving more working room
- Prop walk reduced or gone

CONS:
- PITA to service in far away locations
- Requires haulout for oil changes
- Stray current causes corrosion
- Obviously things I am not thinking of


PS my engine is a Yanmar 4JH2-UTE - 100hp turbo.

[DavidDelRosario]

You mentioned “goosing your engine to get out of the slip”. That’s probably not the best procedure to reverse. Hard throttle in reverse causes prop walk and sends your boat sideways. Easy up on throttle until you get some way on and then your rudder and keel will help reversing.

Dave Del Rosario
Beneteau 373
Kaneohe Bay, Hawaii

[sailingharry]

Given the large number of boats these days with saildrive, it's hard to say "never buy a boat with one." But, it's a serious downside.


Two friends recently buying boats. Four saildrives under consideration. All under 10 years old (under 5, I think).


Modern catamaran (ex charter) had to have one of two replaced within 6 months of purchase. I forget the reason.


Monohull failed survey on rotted saildrive leg. Never been chartered. Yes, could be a maintenance issue -- but describe a shaft installation that can cost that much that soon after new because of maintenance. Worst case is a new prop.


Second monohull (same buyer) a Bene under 5 years old, never been chartered. Well under 1000 hours. Delivery captain had to put in partway up US East Coast, saildrive needed replacement. Again, I don't recall the reason (believe it was related to seals and water intrusion.)


The manufacturers are conservative, to be sure, but they state that the bellows are good for 5 (could be 7?) years, and are not a DIY job -- total bill around $5000. That's $1,000 per year!


Then compare to my 1979 Sabre. A PO replaced the shaft seal with a dripless option, so there was some maintenance. In 2012, I replaced the entire shaft, cutless, shaft seal, and coupling, all for around $500.


We didn't have to make the decision, as the current boat choice developed into a design that didn't do Saildrives. But if you want a Bene/Cat/Jen/Lagoon/FP/Leopard/etc, you are stuck.


All of that to say that I might consider buying a boat that had one, but I would NEVER consider that huge liability as a choice!

[stormalong]

Originally Posted by DeValency

I can definitely agree with your idea of going to a sail drive setup. A V drive was a stupid idea to start with, especially with monohauls. However, the cost of doing it, in your boat may be extremely high. If you have aft berths/center cockpit with an aft master cabin it would probably be impossible- let alone the (prohibitive) costs involved.

Why do you call a V drive a stupid idea? I have owned a boat with a V drive for almost 30 years now with no significant issues, certainly fewer issues than many sailors I know with conventional transmissions.

[DeValency]

The OP listed the reasons really well. You get the wrong prop position, difficult servicing access etc. Sail drive came as the reasonable successor. You are talking about your own subjective experience and I guess you maintained things really well. How many newer mono boats (north of say 1995) do you know with V drive?

Originally Posted by stormalong

Why do you call a V drive a stupid idea? I have owned a boat with a V drive for almost 30 years now with no significant issues, certainly fewer issues than many sailors I know with conventional transmissions.

[DeValency]

Couldn’t agree more!
Now to the economics behind it:

For the boatbuilder, a sail drive engine cost is almost similar (or in fact, lower!) to shaft - why? For the engine vendors, a sail drive generates x10++ income over the engine life... complex unique spares, seals, failures...

And building a new boat is way easier with a sail drive! So they save even more.

Moving the problem to the future owner 5 years or less down the stream.

As always, follow the $$$ and you almost always get the (frequently sad) truth.

****

Originally Posted by sailingharry

Given the large number of boats these days with saildrive, it's hard to say "never buy a boat with one." But, it's a serious downside.


Two friends recently buying boats. Four saildrives under consideration. All under 10 years old (under 5, I think).


Modern catamaran (ex charter) had to have one of two replaced within 6 months of purchase. I forget the reason.


Monohull failed survey on rotted saildrive leg. Never been chartered. Yes, could be a maintenance issue -- but describe a shaft installation that can cost that much that soon after new because of maintenance. Worst case is a new prop.


Second monohull (same buyer) a Bene under 5 years old, never been chartered. Well under 1000 hours. Delivery captain had to put in partway up US East Coast, saildrive needed replacement. Again, I don't recall the reason (believe it was related to seals and water intrusion.)


The manufacturers are conservative, to be sure, but they state that the bellows are good for 5 (could be 7?) years, and are not a DIY job -- total bill around $5000. That's $1,000 per year!


Then compare to my 1979 Sabre. A PO replaced the shaft seal with a dripless option, so there was some maintenance. In 2012, I replaced the entire shaft, cutless, shaft seal, and coupling, all for around $500.


We didn't have to make the decision, as the current boat choice developed into a design that didn't do Saildrives. But if you want a Bene/Cat/Jen/Lagoon/FP/Leopard/etc, you are stuck.


All of that to say that I might consider buying a boat that had one, but I would NEVER consider that huge liability as a choice!

[stormalong]

Originally Posted by DeValency

The OP listed the reasons really well. You get the wrong prop position, difficult servicing access etc. Sail drive came as the reasonable successor. You are talking about your own subjective experience and I guess you maintained things really well. How many newer mono boats (north of say 1995) do you know with V drive?

Well, I have not taken a survey so I don't know how many V drives have been built since 1995. To me putting anything aluminum in seawater is dumb. Entire hulls excepted.

Prop position is easy - I have a feathering prop. To me pulling a 44 lb transmission off is a lot faster, easier and cheaper than hauling the boat out. YMMV

So, I suppose that you have experience with both?

[sailingharry]

Originally Posted by DeValency

Moving the problem to the future owner 5 years or less down the stream.
****

This is the real reason for the success. The first owner enjoys the benefits (lower initial cost, no leaky shaft, more interior volume, etc) and is likely to get out of the boat before the maintenance tail bites back (even with the examples I cited above -- the reality is they are probably "maintenance free" or "maintenance minimal" for 10 years). The problem comes up with the second owner (or when trying to sell it).


Kind of like teak decks -- sells good as an aesthetic upgrade to the first owner, but second owners see that and run (or buy it, and suffer the consequences)! (My friend with two saildrive failures -- one on survey, one on his dime -- is already struggling with caulk failure on his 5 year old teak decks).

[DeValency]

Could agree with everything until the teak deck example was used... Sorry for deviating from the original subject - just because of my very subjective experience with my 28 years old original teak deck on a Contest — one of the very few builders to do the job right from the beginning using 10mm Burmese teak boards with a sub floor (no screws through the glass deck, but in these days deliveries all glued - so look better). With very basic cleaning and maintenance this is how my deck - after over 15 years in the Caribbean and finally now, soon on the way home to Boston. I took this pic three weeks ago in the Bahamas.
But agree that in general teak decks are extremely difficult to maintain, but I’m very happy with mine and seen other Contest, HR, Najad etc. owners as happy as I am.

Originally Posted by sailingharry

This is the real reason for the success. The first owner enjoys the benefits (lower initial cost, no leaky shaft, more interior volume, etc) and is likely to get out of the boat before the maintenance tail bites back (even with the examples I cited above -- the reality is they are probably "maintenance free" or "maintenance minimal" for 10 years). The problem comes up with the second owner (or when trying to sell it).


Kind of like teak decks -- sells good as an aesthetic upgrade to the first owner, but second owners see that and run (or buy it, and suffer the consequences)! (My friend with two saildrive failures -- one on survey, one on his dime -- is already struggling with caulk failure on his 5 year old teak decks).

[CaptWho]

I watched the Sailing Uma YouTube and was impressed with the job that they did. My two concerns were how far forward the prop is now and the indentation in the hull where the sail drive mounts. I'm not sure what effect moving the prop forward is going to cause, but the indentation in the hull is going to fill up with crud and growth.

Sailing Uma Prepping

Sailing Uma Installation

[DanCan]

Originally Posted by DeValency

Could agree with everything until the teak deck example was used... Sorry for deviating from the original subject - just because of my very subjective experience with my 28 years old original teak deck on a Contest — one of the very few builders to do the job right from the beginning using 10mm Burmese teak boards with a sub floor (no screws through the glass deck, but in these days deliveries all glued - so look better). With very basic cleaning and maintenance this is how my deck - after over 15 years in the Caribbean and finally now, soon on the way home to Boston. I took this pic three weeks ago in the Bahamas.

But agree that in general teak decks are extremely difficult to maintain, but I’m very happy with mine and seen other Contest, HR, Najad etc. owners as happy as I am.

Beautiful teak deck! And you have solid lifelines too.

[Souzag818]

Originally Posted by sailingharry

Given the large number of boats these days with saildrive, it's hard to say "never buy a boat with one." But, it's a serious downside.


Two friends recently buying boats. Four saildrives under consideration. All under 10 years old (under 5, I think).


Modern catamaran (ex charter) had to have one of two replaced within 6 months of purchase. I forget the reason.


Monohull failed survey on rotted saildrive leg. Never been chartered. Yes, could be a maintenance issue -- but describe a shaft installation that can cost that much that soon after new because of maintenance. Worst case is a new prop.


Second monohull (same buyer) a Bene under 5 years old, never been chartered. Well under 1000 hours. Delivery captain had to put in partway up US East Coast, saildrive needed replacement. Again, I don't recall the reason (believe it was related to seals and water intrusion.)


The manufacturers are conservative, to be sure, but they state that the bellows are good for 5 (could be 7?) years, and are not a DIY job -- total bill around $5000. That's $1,000 per year!


Then compare to my 1979 Sabre. A PO replaced the shaft seal with a dripless option, so there was some maintenance. In 2012, I replaced the entire shaft, cutless, shaft seal, and coupling, all for around $500.


We didn't have to make the decision, as the current boat choice developed into a design that didn't do Saildrives. But if you want a Bene/Cat/Jen/Lagoon/FP/Leopard/etc, you are stuck.


All of that to say that I might consider buying a boat that had one, but I would NEVER consider that huge liability as a choice!

OK, I actually HAVE a saildrive, so I have first hand experience. Like the rest of the boat, maintenance, maintenance, maintenance...If you don't replace your zincs on your shaft and prop, you'll have problems. If you don't replace the zincs on your saildrive, you'll have problems. Pretty simple concept. Once a year, every June my saildrive zinc gets changed, whether it needs it or not. $30.00



VP recommends changing the seal every 7 years. Mine hadn't been changed in 24, so I changed it. I still have the old one, if any one's interested in seeing it. I twisted it and clamped it between two pieces of wood when I took it out. No cracks, breaks, tears. And yes, it is totally a DIY job! All it took was unbolting the engine from the saildrive, removing a sealing ring and the prop, and pulling the saildrive up. And I'm not super mechanical. I don't know where you got your info from, but it cost me $350.00 for a new seal. I paid the same amount for a new shaft on a previous boat, when the guy I bought it from failed to keep up on his shaft zincs. Maintenance, maintenance, maintenance...

[Souzag818]

Originally Posted by DeValency

Couldn’t agree more!
Now to the economics behind it:

For the boatbuilder, a sail drive engine cost is almost similar (or in fact, lower!) to shaft - why? For the engine vendors, a sail drive generates x10++ income over the engine life... complex unique spares, seals, failures...

And building a new boat is way easier with a sail drive! So they save even more.

Moving the problem to the future owner 5 years or less down the stream.

As always, follow the $$$ and you almost always get the (frequently sad) truth.

****

Curious what sort of drive does your Farr 40 have? Every 40 I've ever seen had a saildrive, right behind the keel, so I'm guessing yours would too. I sailed on a Farr 36 decades ago, and it had a saildrive, Didn't stop you from buying a great, fast, fun raceboat, so it can't be all bad