Oceanvolt Hybrid Motor

[transmitterdan]

Paul is exactly right. Some cruisers don’t think engines are a necessary evil. But no one can argue that having an underpowered (or no) engine improves safety at sea. At least no one with much cruising experience. The Pardey’s eventually gave up cruising in at least some measure because of the rigors of engineless sailing.

In my opinion, “long ago” engineless sailors did not do all that well. In the “old days” open ocean pleasure cruisers sailing modest sloops (there were no cruising cats) had very high mortality rates per mile sailed. Slocum (first RTW cruiser) was lost in an engineless sloop making the mortality rate 100% initially. The good old days weren’t that good. Modern hulls and rigging have improved safety as have reliable engines. It’s unfathomable to me that, in this day and age anyone, would seriously propose cruisers head in the opposite direction. Yet that is exactly what we see people do in order to help justify EP.

[transmitterdan]

Originally Posted by JaJapami

@yvest

The realtime power consumption is measured by the system and displayed in the motor control panels in Watts/kW including rpm. I will try to provide a sample picture of these displays. The general idea is that you set the rpm with the throttle controllers for each motor and the motor controllers will draw as much power as needed to reach the rpm at the propeller. That means the you have different power consumption according to the conditions you are motoring in.



The generator can provide its power directly to the motors and does not need the battery bank to be online. But of course we must ensure that we consume all the power from the Genset (21 kW) when the battery management should be offline. We have done this once when we had to motor into a Le Marin boatyard to figure out what the problem was with a battery that had a bad cell (probably a manufacturing fault as OV said that they had a few more failed cells form the same lot). It worked fine and we did not need the tow help provided just in case it would not work to run the motors directly of the generator.



Overall efficiency is hard to measure. We personally never run the boat on just one engine as we believe that it is resulting in a lot of stress on the one engine running. But this is up to everyone to decide.



The generator consumes somewhere around 5 litres per hours. I don't have the numbers for the 55 hp Volvos that would be standard on the Saba 50, neither on the 75 hp optional upgrade engines. We are happy with the consumption and enjoy the quite times when motoring for the usual distances and times.



Concerning the Servoprops they were not ready when our boat was fitted out. To change our propellers has never been discussed between OV and us. I think it is a great development but it also comes with extra costs. I personally have more trust in the Gori folding props just as a gut feeling as there is more mechanics in the Servoprops that may become a mechanical problem with time. But please this is just my simple thought and I never looked into a change to Servoprops as I said. I am curious to get information from owners of those Servoprops!

JaJapani,

Having a look at the motor core temperature in your photograph I see 125C. If it is the stator core temp then the stator winding wire is about 140C. The rotor winding is probably approaching 155C. That is pretty blazing hot based on several years of electric motor experience.

Do you know what exactly is being measured at 125C. One would think a water cooled motor could never approach those temps. Or are these motors not water cooled?

[BigBeakie]

Originally Posted by transmitterdan

A motor that cannot drive a sailing vessel in bad weather is only a little more useful than a paper weight. If by design one can only depend on it for short periods during good weather then that is a decision that many would find troubling.

Cruising boats never depend on one thing. They layer up systems for maximum safety. Auxiliary propulsion that is capable to run continuously is an important safety feature to the vast majority of cruisers.

Perhaps you didn't comprehend the conversation. It is your spin that this system "cannot drive a sailing vessel in bad weather". On what basis do you make that claim?

JaJapami has a DC genset to be able to motor continuously. Did you miss that part? He has had to use it once, repeat - ONCE, to motor into bad weather. My reading of that event was that despite having sub-optimal performance due to overheating, his OV system got him to port against the bad weather at about the same speed as twin 40HP diesels in a much smaller & less windage Lipari cat in the same conditions.

So, a crippled EP system of 22 HP running around half power was the same performance in bad weather as diesels twice as powerful at full power.

Then you say, by design, the OV system " can only depend on it for short periods in good weather".

What utter rubbish. Clearly, your agenda has been exposed by making such irrational statements.

[transmitterdan]

Most people who die at sea only needed to escape death once. If you think that is rubbish then ok.

[BigBeakie]

Originally Posted by transmitterdan

Most people who die at sea only needed to escape death once. If you think that is rubbish then ok.

Ah, so now the old salt has a dire prediction of doom for any who are so foolish as to contemplate EP? OMG

This gets sillier by the moment.

How many boats have foundered on the rocks and on lethal river bars from a dead diesel with clogged fuel filters???

[Paul Elliott]

Originally Posted by BigBeakie

So, a crippled EP system of 22 HP running around half power was the same performance in bad weather as diesels twice as powerful at full power.

I just don't believe this.

11 HP does not equal 44 HP. In an apples-to-apples comparison -- same boat (displacement, length, hull form, windage), same weather, correctly-pitched prop -- if you need 44 HP of diesel to push the boat at a certain speed, then 11 HP of electric motor will not do the same job.

Change the boat, or conditions, or expectations, then you no longer have a valid comparison.

[BigBeakie]

Originally Posted by Paul Elliott

I just don't believe this.

11 HP does not equal 44 HP. In an apples-to-apples comparison -- same boat (displacement, length, hull form, windage), same weather, correctly-pitched prop -- if you need 44 HP of diesel to push the boat at a certain speed, then 11 HP of electric motor will not do the same job.

Change the boat, or conditions, or expectations, then you no longer have a valid comparison.

Well perhaps I have misread JaJapami's comments on this in post#1283 and a previous post.

As I understand it he in his FP Saba 50 with OV SD15kW (22 HP) was in company with a FP Lipari 40 that had 40HP diesels motoring against a 28-32 Knot headwind with 1.5 to 3 meter seas and they were doing about same SOG at about 3 knots.

His motor controllers were only allowing about half power to be used in his 15kW motors and he had alot of hull growth.

Perhaps the Lipari engines were just ticking over? But, I doubt it.

[Heath68]

I agree, 11HP does not equal 44HP and I can't read anywhere in #1283 that suggested the Lipari was at full power.... But I think some are missing the point. Surely the purpose of a propulsion system is to assist your sailing? If the OV system could push my boat away from a danger in a 40knot headwind and rough seastate I'd be happy. Me being me I'd try to avoid such weather in the first place or if I was a better sailor then maybe I'd just pick an alternative safe line of sailing that missed the danger ahead of time. I'm sure the OV is not all things to all people but for JaJapami & many (me included) it would be fine as our style of sailing suits it. This is exactly why some of us here love cruising cats, others wouldn't touch them with a barge pole... These choices are ours. I am personally very grateful for this thread and JaJapami's input as it gives us knowledge for personal consideration.

[Paul Elliott]

Please don't mistake my insistence on being realistic as an attack on the concept of electric drive. I am quite impressed by the efficiency improvements and power density of modern electric propulsion system components. I just don't think that magical thinking helps in the long run. It leaves people disappointed (the early Lagoon electric systems) and doesn't help advance the technology. I wish that battery technology were even close to being on parity with diesel fuel when it comes to energy density, but it isn't, and I see nothing game-changing on the horizon. Even if solar panels were to somehow become 100% efficient, most boats (like mine) would not be able to carry enough to cover my electric propulsion needs (or to be honest, my desires).

Other people, other boats, may find these necessary compromises (or reductions in available power) to be entirely appropriate for their needs. I will continue to follow their progress with great interest.

[BigBeakie]

Originally Posted by Paul Elliott

Please don't mistake my insistence on being realistic as an attack on the concept of electric drive. I am quite impressed by the efficiency improvements and power density of modern electric propulsion system components. I just don't think that magical thinking helps in the long run. It leaves people disappointed (the early Lagoon electric systems) and doesn't help advance the technology. I wish that battery technology were even close to being on parity with diesel fuel when it comes to energy density, but it isn't, and I see nothing game-changing on the horizon. Even if solar panels were to somehow become 100% efficient, most boats (like mine) would not be able to carry enough to cover my electric propulsion needs (or to be honest, my desires).

Other people, other boats, may find these necessary compromises (or reductions in available power) to be entirely appropriate for their needs. I will continue to follow their progress with great interest.

But Paul, there is no magical thinking about this at all. Did you read the cruising speed JaJapami is getting with his 15kW motors? On a fully loaded Saba 50, no less?

How can that be? I mean, is he wrong? Is he delusional? Is he a liar? Or is it possible you do not yet comprehend the effect of higher efficiency and torque output given by the electric motors?

And you may recall that many here, in this very thread, said my statements about aiming for ( with a lighter more slippery cat, mind you) 7 knots using 7kW to each motor were fantasy and hype, and even like religious delusion.

And yet Kato, another real world example given in this thread with heaps of data gathered, by the way, gets exactly that performance. So where is the magical thinking?

And the owner of Kato says the diesel equivalent of his 15kW Oceanvolts would be, at least, 50 HP diesels. He should know, he had 75HP Yanmars in his last boat which was 6 foot shorter that Kato, similar design from same designer.
And I have heard the same story from other OV owners who just simply say the electric pushes their boat into weather better than their previous diesels.
That is why we decided to go for the new Servoprop system. Testimony from users. Users that have had previous diesel sailboats for a lifetime.

I wish some of them would contribute to this thread.

[transmitterdan]

It is mathematically impossible for an electric motor powered by an inverter which is in turn powered by a diesel genset to be more efficient than a diesel directly connected via a transmission to a prop shaft. It requires magical thinking to believe otherwise. A kW is a kW no matter from whence it comes. Torque is not kW. There have been technical errors in the reports here. For example, torque is the same throughout the speed range of the EP was claimed. That is exactly backwards. Torque decreases with speed. KW is approximately constant with speed thus torque is much higher at low speeds. No one has taken the same 2 boats, one with EP and one with typical diesel, in same difficult conditions and motored for 24 hours and reported the distances covered. If EP is so obviously better or even equal to mechanical and I were selling EP that is exactly what I would do. It would put all the doubters to bed forever.

As I have said, I am a big fan of EP. I hope it can one day replace smelly diesel. But as of right now that day is well into the future except for a small minority of sailors who can understand and accept the unavoidable compromises. Good on them.

[Matt Johnson]

Originally Posted by transmitterdan

I hope it can one day replace smelly diesel. But as of right now that day is well into the future except for a small minority of sailors who can understand and accept the unavoidable compromises. Good on them.

The issue I keep seeing is people with zero cruising experience deciding to ditch their diesel for electric drives. It's easy to think you know what you need, but until you experience travelling via a sailboat, anecdotal information can be dangerous.

A Freeflow cat with high quality Oceanvolt system is great for testing and refining the technology.... kind of like the electric Formula 1 will hopefully trickle down to normal consumer level cars. But, the onslaught of people with round the world ambitions, low budget, heavy old boats, and zero experience is going to lead to a lot disappointment.

The Oceanvolt is awesome and I'm so happy someone if putting their money where their mouth is, but I hope everyone acknowledges this Oceanvolt/Freeflow combo isn't the same as a DIY electric motor in a Westsail 32.

Matt

[Paul Elliott]

Originally Posted by BigBeakie

But Paul, there is no magical thinking about this at all. Did you read the cruising speed JaJapami is getting with his 15kW motors? On a fully loaded Saba 50, no less?

How can that be? I mean, is he wrong? Is he delusional? Is he a liar? Or is it possible you do not yet comprehend the effect of higher efficiency and torque output given by the electric motors?

I don't know how this can be.

I merely suspect that we are comparing apples to oranges. For a given boat it takes a certain amount of energy to spin a prop. RPM and torque are the parameters and KW or HP are just different names for the same thing. If the prop is sized or pitched differently there will be different "sweet spots", but I suspect that if you downsized a diesel to match the KW delivered by an electric system, and specified the propeller to match, the performance at full-power would be identical. It really can't be otherwise -- that would be magic.

I can easily believe that an electric drive is more efficient at getting the boat out of the slip in into the bay. But that's not what we seem to be discussing.

[ssmoot]

Originally Posted by Paul Elliott

I just don't believe this.

11 HP does not equal 44 HP. In an apples-to-apples comparison -- same boat (displacement, length, hull form, windage), same weather, correctly-pitched prop -- if you need 44 HP of diesel to push the boat at a certain speed, then 11 HP of electric motor will not do the same job.

Change the boat, or conditions, or expectations, then you no longer have a valid comparison.

I agree.

Except "44hp" is purely marketing if you don't actually use it. Hooning about aside, how often, for how long, are cruisers, out of necessity, running their boats at redline?

Because that's the only time you've got a "44hp" engine.

When taking the lumpy torque curves into account, it's my suspicion that most cruisers would be served perfectly fine by an EP system rated for a much lower peak output as it would have a much more usable powerband.

My 125kw EV (Chevy Bolt) is almost as fast (0.7s slower 0-60) as my previous gas/turbo vehicle (Volvo S90 T6) with twice the horsepower off the line. It also has a lot more usable power as it never has to worry about suboptimal shifts, warm or cold starts, turbo lag, etc.

The price you pay is that it's geared to give you all that power up until it's "redline" at 90mph. So you're not gonna be blazing down the Autobahn at 150mph.

The gas engine needs 316hp not because it needs 316hp, but because it spends the vast majority of it's life outside of it's powerband and you can't increase the low-end without increasing the top-end number. Between 2,000 to 4,000 RPM it's actually an 80hp to 200hp motor.

Which then explains how the EV can be so competitive. Within the range they're actually used, the vehicles (~3,600lbs and ~4,100lbs respectively) have very similar power to weight ratios.

Ah, but the EV doesn't have the peak, top-speed performance of the ICE vehicle.

That's true. But on a boat we're talking about a ~20% difference in top speed perhaps? And again, for how often and for how long?

As a former motorcyclist, I can't count the number of times someone tried to tell me "power" saves and was able to get them out of a squirrely situation. On the road at least, the only power that factors into safety is the power of your brakes/tires. You can try to use a contrived example to demonstrate hp saves, but guaranteed that same hp also encouraged you to put yourself into more dangerous situations as well. There's a reason insurance adjusters don't give you a discount for opting for the bigger engine.

So, I have very little on-water experience. When I hear that you need that (peak only!) horsepower to run from weather or something, it may be unfair, but I mentally put that into the same category as the 20yo sport-bike rider telling me that what saved him from that truck about to t-bone him was the 150hp between his knees. When it's much more likely defensive driving, brakes and a well maintained bike would come out on top 99% of the time.

tl;dr: "hp" is a marketing number that only refers to peak performance, and I feel like there's an over reliance on it in these conversations. Guaranteed your new 45hp Yanmar has much more usable power with a flatter torque curve, better response, better power-to-weight ratio, reliability, (MTBF, not some story about how bullet-proof the block may be) long etc than some 50 year old engine with the same peak rating as well, but to read these conversations you'd think the only thing that mattered was a peak rating that's (I suspect) almost never used, even in the worse conditions. Because who thinks a bad storm is a great time to test running at redline for hours? But that's just me speculatin'.

If I'm totally off base with how you guys are actually using your engines in the water, I'd love to be set straight. I'm sure I could learn a lot from your experiences.

[Paul Elliott]

I seldom run my 50HP Yanmar at top RPM. Most of the time I get by at not much more than a fast idle, since I'm trying to stay efficiently below hull-speed for maximum range. There have been a very few times when I cranked the throttle to near max, but I can't honestly say that it was a life-or-death situation. And if it had been, perhaps I would have needed 100HP? Many similar boats have much bigger engines than mine. Or perhaps we could comfortably get by with much smaller engines -- people certainly did in the good old days.

None of which proves that an electric HP = 3x diesel HP. But that is what some people have been claiming.

And by the way, look at the power curve for a fixed-pitch prop. At low RPMs the shaft load drops off much faster than the diesel engine torque does. So we don't need that more-powerful diesel just to get torque for low-speed maneuvering. Locomotives need zero-RPM torque, and that's one reason they use electric motors. Boats don't need that torque characteristic.