Sail boat engine choice - electric or diesel

[rla]

My Volvo MD2 is that age too.
As stated elsewhere do the injector if its not been serviced for years.
the most likely cause of low revs is a restricted exhaust bend, after the water injection point and or a partially blocked exhaust hose. A tremendously hard material is deposited in both areas and usually it's so difficult to remove a new bend and exhaust hose is required and gives dramatic improvement.
For a few hundred you'll save yourself thousands in engine swap 'on costs' which are huge and always unplanned.

The electric option is not there yet as so many have sensibly pointed out, its way to expensive and way to short on distance at normal acceptable cruising speeds.

[seandepagnier]

Originally Posted by jtaylor

Keep in mind what I mentioned earlier about windage and current impacting range... I have been out in more or less ugly conditions for my area. a 25kt headwind and short chop can bring a boat near to a standstill. I was able to make only about 2kts over ground against the wind, chop and current. With a "2 hour" battery, will you be able to get to shelter within 4nm?

Yes, you would quite easily make shelter, the same way I made shelter without any mechanical propulsion at all. It is critical to have small strong headsails, 3 reefs in main and the confidence and experience to tack in 2-3 boat lengths.


All of your numbers for electric propulsion are off, because your 12 inch propeller is tiny! It's no wonder you need shore power to charge as opposed to solar which would be more than enough.


Imagine the first person to use a mast taller than 6ft being ridiculed for having such a tall and ridiculous mast that you can't even reach the top of! But he wants efficient sail power so it's worth it. the same is true of propeller size, and virtually every cruising boat is _wasting_ energy be it electric or diesel power, it is churning water and at optimal speed maybe only 20% efficient as opposed to 85% with a much larger prop, this is a _huge_ energy difference.



You can sail in and out of every inlet on the east coast in most any weather. You can sail without any kind of motor everywhere in the cruising world. I have been in atolls which have a pass on the lee: you can tack through!! I have been through canals, to many harbors which I was told were impossible without an engine!


The engine or motor other than navigation in a harbor (which is not limited by batteries anyway) only maybe gets you somewhere sooner, and in most cases the difference is irrelevant if you anchor most of the time anyway. If you really want to get places faster you should get a trimaran, not an engine.



Sailing in the open is simple and requires no practice and very little skill. Difficult sailing is in narrow areas with strong currents steep waves, limited wind power and obstacles. Most cruisers _refuse_ to learn these skills rather than practice and improve them.


The emissions of diesel produces makes it a non-starter for recreational activities. To push this burden on to future generations, and it will be looked back on as slave owners of the past "justified" their selfish actions. In other words: it is not a fair choice to use diesel if it it is a criminal behavior.

[newhaul]

Originally Posted by seandepagnier

Yes, you would quite easily make shelter, the same way I made shelter without any mechanical propulsion at all. It is critical to have small strong headsails, 3 reefs in main and the confidence and experience to tack in 2-3 boat lengths.


All of your numbers for electric propulsion are off, because your 12 inch propeller is tiny! It's no wonder you need shore power to charge as opposed to solar which would be more than enough.


Imagine the first person to use a mast taller than 6ft being ridiculed for having such a tall and ridiculous mast that you can't even reach the top of! But he wants efficient sail power so it's worth it. the same is true of propeller size, and virtually every cruising boat is _wasting_ energy be it electric or diesel power, it is churning water and at optimal speed maybe only 20% efficient as opposed to 85% with a much larger prop, this is a _huge_ energy difference.



You can sail in and out of every inlet on the east coast in most any weather. You can sail without any kind of motor everywhere in the cruising world. I have been in atolls which have a pass on the lee: you can tack through!! I have been through canals, to many harbors which I was told were impossible without an engine!


The engine or motor other than navigation in a harbor (which is not limited by batteries anyway) only maybe gets you somewhere sooner, and in most cases the difference is irrelevant if you anchor most of the time anyway. If you really want to get places faster you should get a trimaran, not an engine.



Sailing in the open is simple and requires no practice and very little skill. Difficult sailing is in narrow areas with strong currents steep waves, limited wind power and obstacles. Most cruisers _refuse_ to learn these skills rather than practice and improve them.


The emissions of diesel produces makes it a non-starter for recreational activities. To push this burden on to future generations, and it will be looked back on as slave owners of the past "justified" their selfish actions. In other words: it is not a fair choice to use diesel if it it is a criminal behavior.

I will stick with my Volvo md2 and rebuild as needed electric is not any good for my use case . I infact have removed several and replaced them with diesel for people . Electric is just not there yet and I suspect won't ever reach that point untill the battery storage issue is solved.

[jtaylor]

I see so many boats that are equipped to cross oceans that never do. It’s like the armchair quarterbacks that never actually play any football. People saddle themselves with systems, maintenance schedules, worry about resale values all in the name of pursuing someone else’s ideal of what a proper safe offshore cruising boat is. They equip their boat to that level, spend the money and the time and never actually go anywhere. You can find the same people “trekking” up little hills in their top-end gear. If all you ever do is sail around the buoys or marina hop, electric is more than adequate. If you only ever do the occasional short “voyage”, some fairly basic planning can make it possible with electric propulsion.

I’m curious as to where all these removed electric propulsion systems are? I don’t think I’ve ever seen a used one for sale anywhere. So either there is an extremely voracious demand for these previously owned systems or there is a global conspiracy hiding the failure And inadequacies of electric propulsion By ensuring that no one ever sees dissatisfied customers and gets disillusioned. There are enough people repowering these days in any marina that at least some small yet significant percentage is considering electric. I think a small, portable, quiet, water cooled diesel DC power source would do wonders for electric auxiliary propulsion. It would allow the driveline to be electric and give the owner the option for diesel as needed. Remove it for club racing and day sails, bring it along for trips. Bring it in to the mechanic for regular servicing instead of paying the mechanic to come to you... That also has to be worth something ;-)

It’s not that electric is not “there” yet. It is “there” for certain values of “there”. The task no is to push the definition of “there” to include more “there’s”. And that can be done incrementally, piece by piece. Boat by boat.


Another advantage someone had brought up earlier is the idea of electric cooking. Induction cooktops and microwaves that were traditionally thought of as huge power sucks are actually not that bad. The total energy required to boil water, fry an egg, simmer a sauce or whatever isn’t that much in the grand scheme of things. And large propulsion batteries can allow for such luxuries without killing a 12V inverter. A 48V 2000W inverter will only draw 50A on the DC side.much better than the 200A a 12V inverter would draw. So cabling And fusing can be smaller. Also, the energy storage is there. If you’ve got a couple of large solar panels (solar Bimini top with two 250W panels, for example) that gives you 500W as long as the sun is shining. That means about 2kwh into the batteries every day it’s sunny.While not enough to refill a 20kwh battery pack (about 350lbs of LiFePO4) every day, not many people consume all that energy every day either. 2kwh is enough to run decent refrigeration, electric cooking and perhaps a few creature comforts (but not AC. If you have enough solar to run AC, I put forward that What you’ve got should not be classified as a boat...) So it would be possible to anchor somewhere, and refill your batteries over a few days as well as cook your food and never have to stop for propane or diesel or anything. Your boat’s limits to how long it can be out there are now only limited by the human crew’s needs. Water in, black water out, food and waste disposal. This won’t work if you’re doing a Great Loop, or transporting a boat on a schedule. That particular “there” is certainly in the “not quite there” camp. And it will remain there for the foreseeable future. But the edges of acceptable use cases for electric propulsion are moving outward, faster and faster. I agree the manufacturers that came out with electric options 10 years or more ago were a little too early to the game. But manufacturers offering electric options on new boats today? There is something there. There is a market and a growing one at that. There will be a good second hand market for electric boats fairly soon. Us early adopters will likely always have hard-to-sell oddball boats because our boats will not have all the systems integration that will come standard on a modern OEM electric propulsion package. We’re like the enthusuastic car owners in the early-mid 90s that integrated aftermarket satnav, Remote car-starters, in-car entertainment systems, backup cameras, and pioneer 100-disc CD changers in the trunk. A mishmash of cool tech that just didn’t integrate well and was never valued by the next purchaser of the car.

[john manning]

Originally Posted by jtaylor

@John Manning: see one of my previous posts about the main steps to converting. The tow test is actually fairly important if you wish to get a fairly otpimized system. That's the only way to get real data of hull resistance through the water without factoring in efficiency losses of components of the drive system.

As for the 18kw system proposed by the OP, always be wary of power claims of systems. That 18kw is probably peak power. Peak power in marine diesels is the 1-hour rating. Peak power in industrial motor/controller systems is a 1 or 2 minute rating.

The Sevcon controller in question is the Gen4 Size 6 controller.
The 550A rating is 2 minute.
The continuous rating is 220A.
And the motor in that kit has a continuous rating of 157A.
So the continuous (24/7 usable) power of the setup is limited to pack voltage * 157A.
So about 12kw at 72V nominal or 7.8kw at 48V nominal (just over 10hp)

In my system, the 2 minute rating is 275A.
The continuous rating is 110A.
110A @48V nominal is about 5.5kw or just over 7hp.

My Yanmar YSB8 has a 1hour rating of 8hp and a continuous rating of 7hp.
My boat claims to displace 7500lbs, I've always used 8000lbs or even just 4000kg in my estimates.

My system is/was sold by Electroprop as a 5.5kw system.
The same components are sold by others (Thunderstruck among them) as 10kw systems.
One thing I really like about ElectroProp is his apparent under-rating of his systems. He always quotes continuous power. Marine propulsion applications are always going to be continuous power. We never have a need for those 1 or 2 minute peaks so anyone who advertises them is being a little disingenuous.

His boat is probably fairly similar to mine -- about 30', about 8000lbs.
His power needs will also be similar.
Lets assume he fits that 18kw system.
Even if he puts the throttle all the way down with a prop that can get him to hull speed the following will happen:
1) the boat reaches hull speed and the prop reaches the rpm requested by the throttle but max power is not developed. Not a big deal, but you may have bought more motor/controller than your boat can use. It's only money... You could probably turn off the water cooling and just run the motor as a sealed unit without overheating.
Or...
2) the prop is way too big and aggressive. Again at full throttle, the motor will try to spin at 2500rpm. It will use all available power to do so. If the prop is too aggressive and is trying to spin at 1000rpm but hitting too much resistance from the water, more power will be drawn. Some sort of equilibrium will be reached. if 2500rpm can't be reached, then controller max power will be hit and that's where things will stay until battery runs out or things heat up too much and the controller claws back power.

Basically, you want to have your controller max power being reached at the same time as your boat hits hull speed, at the same time as your prop is hitting that 1000rpm and motor at its max rpm for your voltage.

The prop on my boat could actually stand to be a little bigger. I am hitting max throttle before I'm hitting max power. But performance is good enough. 6kts at 80ish amps is fine. The controller and motor coils never get above 65C in 6 years / 7 seasons. However, going for a 14" did 14" pitch would have been more expensive and not as readily available. I went for readily available anywhere, easy to find and relatively affordable standard components instead of per-optimized exotic bespoke engineered components.

The thunderstruck kit uses the same Sevcon Gen4 line of controllers which are amongst the most efficient brushless motor controllers on the market. They support regen, and allow an insane amount of configuration (if you have the equipment). ElectroProp configured my controller and gave it its personality. Thunderstruck will do things a little differently. Perhaps the acceleration/deceleration ramps are different. Perhaps throttle behaviour is different (linear as opposed to logarithmic or some other custom curve. Perhaps they characterize their motor differently than has ElectroProp. That is definitely something to get from a knowledgeable source - a complete system integrator, such as ElectroProp, Electric Yacht, Thunderstruck, etc will all have configured their controller for a specific motor. Had I just bought a pile of components, I would have been stuck with defaults or I would have had to purchase the controller interface (hundreds$$ if I recall). Anyway, ElectroProp built in a few tweak-able parameters that I can change from within their Sevcon ClearView Display menus and they have served me well in optimizing my setup. If I change props, I'll have to revise those option, but I know they're there.

That is a very interesting page of information. Thanks for the detail. It lets me know what a DC system would look like.

My intention at the moment is to use a 400V 3 phase AC drive. Because my business works on ships with medium voltage diesel electric drives it is a technology I am comfortable with.

The DC option presents some advantages, especially the ability to operate on battery power for short periods. I had not considered it because I had very little information from real applications. So again your detail has very very helpful.

[wingssail]

Originally Posted by carstendenmark

I live in Denmark, and most people do coastal sailing.
My setup is not meant for world cruising.
However, please watch Youtube "Sailing Uma", a pure electric live-aboard 36' sailboat who criss-crossed the Caribbean and now also crossed the Atlantic.
The electric motor can recharge when sailing by sails.

People buy a sailboat for sailing, not motoring, in my mind :-)

You asked, which kind of boat would I buy? Answer: Diesel, absolutely!

People, (like Sailing Uma) are going to be sailing or they are going to be stopped. I am a sailor, more than anyone, but I need my motor far too much to depend on an electric which gives me 10 miles range, at best, can never be recharged by solar and recharging by sailing is a joke fraud.

You want to avoid diesel fumes below, no more oil spills, no more oil and filter changes and are looking for low maintenance, low overall noise level and sufficient power in rough conditions? I don't have diesel fumes below, I don't have oil spills, and oil and filter changes are periodic, and not difficult. My engine is not noisy, it is low maint. and it has heaps of power, for days if needed, and I don't have electric.

[carstendenmark]

Thanks all, for the very useful replies !

When I bought the boat, the former owner had placed an outboard rack at the transom (!) which I removed.
Seems that he was not certain, that the diesel would be working at all times...

I don't know if it is something about the hull's aerodynamic design, but when motoring, the exhaust fumes comes back into the cockpit.
We can hardly talk when motoring, even in the cockpit, caused by the noise.

A new fitted 18HP Nanni engine will cost 14K US$, ready to go.
And might not help the smell, noise, diesel refilling, etc.
So, convinced by the non-circumnavigating statements here, I will go for an electric conversion. I'm a DIY (mechanic engineer), so I'm not afraid of the challenges.

I will not start out underpowered, so a 48V complete balanced system with 10-12KW will do fine. Electroprop seems to have a fine solution.
A large prop, like a 2-blade Flexifold 16"x12" with reduction gear will give a nice torque (has to be calculated).
I will consider to modify my Volvo saildrive 100S to fit a vertical mounted motor.
Mount a new extended vertical shaft, and blind off the reverse and engine shaft holes.
If not possible, then install a new straight shaft drive with a horisontal motor.
This even eliminates the expensive maintenance of a saildrive.

A portable 48V 2-3KW generator and a jerrycan can be onboard for longer passages into the Baltic Sea, just for safety.

LPG is a no-no for me in a boat, so using induction cooker and microwave will do nicely.

No regen at my humble 6.8 knots hull speed.

Foldable solar panels can be rolled out during anchoring and mooring.
These can even be set up to face the sun, not like static mounted panels.
More efficient.

Sailing a boat takes some planning before heading out, and if the weather is forecast to be too rough for my little family, we do not start a passage at all.
When I am going singlehanded, its a different story.

*** The cost of the complete system is not of high priority.
The main aim of this is to get my family out on the water with me, and my daughter to grow up as a sailor :-)

Those of you who already have experience with electrosailing (especially in salty waters), did you had any corrosion problems of the system so far ?
I looked up Electroprop, and they seems to have understood the problem in their setup.

ANY input is valuable input. Thanks, guys !
And thanks a lot to Kika and Dan at Youtube "Sailing UMA" for inspiration !

[gonesail]

Originally Posted by seandepagnier

You can sail in and out of every inlet on the east coast in most any weather.

[Gonsena]

Originally Posted by Thumbs Up

You guys do know that "Uma" ripped out their electric and installed a diesel? You might just be over propped.

Can you link that video here? I'm not so sure this happened.

Also learningthelines have gone electric, used the boat and have a better analysis on battery used. They went full electric and said the stove was the battery drainer. Also they used the cheap electric engine option 10k USD for 14kw vs 24k usd of oceanvolt

[DeValency]

Originally Posted by Thumbs Up

You guys do know that "Uma" ripped out their electric and installed a diesel? You might just be over propped.

No, we don’t know, as what you’re posting here is a pure faked BS claim.

This was uploaded by Sailing Uma two days ago. Well done like all their videos and if you watch (or scroll) to the last 5 minutes you can watch their new electric propulsion in action. Few months ago they upgraded their original electric motor - after 5 years or so, with a new one, while also changing to sail-drive. All of it, mostly DIY installation.

https://youtu.be/_0m4Nub9PRM

[Rightbrainer]

Sailors like those on S.V. Uma have no particular deadlines and can wait for the weather and tide slot that they're looking for. If that's you, you barely need an auxiliary, just like them. Enjoy the quiet and the extra space. You'll also need to strip off those panels to protect them from big storms that come your way.

If you weekend cruise and day sail and need to be back at the dock to go to work at a certain time, then eventually, you'll probably need to chug through some combination of currents, tides, headwinds, and doldrums to make that happen. An extra jerry can of fuel can relieve a lot of pressure. If your range isn't adequate, you won't be able to venture out under semi-unfavorable conditions and you'll just have to bob at the dock/mooring when you could be sailing. Abundant hot water is a plus, too!

[SailMoonShadow]

Originally Posted by Thumbs Up

You guys do know that "Uma" ripped out their electric and installed a diesel? You might just be over propped.

No they haven't! They took out their old forklift motor and put in a boat specific one with saildrive.

[SailMoonShadow]

Originally Posted by carstendenmark

Dear sailors

I am aware that the range is limited to the battery bank's capacity, so I will dimension the battery banks for 2 hours of sailing at 5.5 knots
Here is my questions for you :
1) If YOU were to buy a used sailboat with a new engine, would you prefer an electric or diesel engine ?
2) Anyone of you with user experience of the reliability and use of electric motors in sailboats ?

1. I don't think I'd have a preference when buying a second hand boat but if I were ever in the position to order a new one I'd specify electric. In fact I've already made the decision to replace my old Volvo with an electric drive when the Volvo eventually dies. Until then it doesn't make economic sense to change it. If your Volvo is definitely dead then go for it, otherwise it would be cheaper by orders of magnitude to keep the diesel going. A new electric system is going to be €8000+++!

2. I don't have any personal experience but know people with electric drives and they all rave about them.

A lot has been said about range with electric drives but I'm kinda with you - a sailing boat is for sailing! The idea that you can motor out of bad weather is a fallacy irrespective of what drives the boat!

Lee shore? Really? If you are being blown on to a lee shore you've made a navigational error and whether you are powered by electric or diesel you're in trouble!

No wind (or very little)? This is the only time mechanical propulsion will move the boat faster than sailing! If you are coastal sailing you've got two or three hours at least (I think Uma reckon on ten) so plenty to get yourself back to a port or anchorage. If you are offshore, well, just suck it up and wait for the wind to arrive - like the Rigging Doctor did on passage from the Azores to Porto.

[newhaul]

Originally Posted by SailMoonShadow

.

A lot has been said about range with electric drives but I'm kinda with you - a sailing boat is for sailing! The idea that you can motor out of bad weather is a fallacy irrespective of what drives the boat!

Lee shore? Really? If you are being blown on to a lee shore you've made a navigational error and whether you are powered by electric or diesel you're in trouble!
.

A diesel will get you out of trouble if you find yourself in it.

There are places where you would literally not be allowed to go with an electric drive due to the lack of range .
Don't try to go through the Panama canal or the Suez canal with electric you don't have the required range without diesel generators.
.

[Mauruuru]

I have a 2010 Seaward RK32 bought new in 2010 with a 30 HP Yanmar that took me reliably everywhere. But as a power engineer and RE developer I knew I was going to convert her someday to electric propulsion. That day has arrived.I removed and sold the diesel and replaced it with a 20kW motenery PMAC motor and sevcon controller. Using carbon Foam Firefly AGM batteries.
Stage 1, motor/controller/batteries installed and tested. Stage 2, e propulsion endurance in progress. Stage 3 future mods for range extension off shore.
BTW sale of Yanmar paid for the motor/controller.