Oceanvolt Servoprop regen tested by UMA

[Tupaia]

There is a major problem with perceived power obtained from regen on fast light cats. It only takes a tiny amount of drag (regen) and you are no longer doing 200 plus mile days. I experimented with a max prop, locked in reverse and at 8 knots would have produced 4hp under load but reduced the sailing speed by 20%. I had shafts with belt drives so my losses would be higher that a modern electric pod but the drag from even a freewheeling propeller locked in reverse is significant. Also the design of a propulsion propeller is not the same as a regen propeller. Regen works on vehicles because of the need to slow down (brake) and the fact that there are hills on land. The whole idea of using regen to generate electricity is an anathema to a cat that is designed to sail "fast".

[CaptainRivet]

Originally Posted by Adelie

I see it the other way. EP (Electric Propulsion) is not particularly good for day or weekend trips but much better suited to long offshore passages. For day and weekend trips one usually has a deadline to be home for work or family. If you are going offshore you shouldn't have a schedule so sitting and waiting for wind or sun shouldn't be that big an issue.

Jimmy Cornell's problem wasn't with the EP, it was with the regen. It's not clear if it didn't work as advertised or he didn't have his consumption under control or some of both. I suspect it was mostly lack of control of consumption coupled with regen underperforming somewhat. Whatever, he didn't take as much solar as he should have.
I have no info on what happened with the others. Lack of solar, failing to control consumption, inappropriate use expectations.

Certainly there are examples of boats such at Uma, Wisdom and Saoirse that have done significant passages and coastal sailing using just EP. I believe they have all installed significant solar capacity, have kept control of their house consumption and managed their expectations of what EP could provide them.

Living with EP successfully requires accepting the tradeoffs. If you don't want to accept them, don't but don't try to argue that it doesn't work because it wouldn't work for you.

The problem is the whole EP system, regen, battery bank, solar....its only as good as its weakest link, in one boat its not enough solar, on next not enough regen and next small bank due to payload...and on the other side a 3cylinder 30hp beta is 7000Euro and very relaible plus with 400l diesel tank gives you 700-800nm pure motoring with a big alternator 130A charge inclusive.

[CaptainRivet]

Originally Posted by Tupaia

There is a major problem with perceived power obtained from regen on fast light cats. It only takes a tiny amount of drag (regen) and you are no longer doing 200 plus mile days. I experimented with a max prop, locked in reverse and at 8 knots would have produced 4hp under load but reduced the sailing speed by 20%. I had shafts with belt drives so my losses would be higher that a modern electric pod but the drag from even a freewheeling propeller locked in reverse is significant. Also the design of a propulsion propeller is not the same as a regen propeller. Regen works on vehicles because of the need to slow down (brake) and the fact that there are hills on land. The whole idea of using regen to generate electricity is an anathema to a cat that is designed to sail "fast".

Absolutely agree, all true. But with a fast cat when cruising you mostly depower it and with regen you simple less depower it as that breaks anyhow.

I had a simple shaft gen on my old 40ft longkeeler ketch and that was slow as f... 5kn... but that shaft gen consist of a 600W wind turbine and was just just connected with a ripped timing belt to the shaft in 1:2 ratio and it delivered constant 25A while costing me 0.3-0.5kn...had a freewheeling 4 blade fixed prop anyhow no folding prop would fit due to skeg.
But 25A constant when i am underway, closed the gap the solar panels lost when on passage due to shading of sails etc.

[Adelie]

Originally Posted by CaptainRivet

The problem is the whole EP system, regen, battery bank, solar....its only as good as its weakest link, in one boat its not enough solar, on next not enough regen and next small bank due to payload...and on the other side a 3cylinder 30hp beta is 7000Euro and very relaible plus with 400l diesel tank gives you 700-800nm pure motoring with a big alternator 130A charge inclusive.

You imply that if all the parts of the system were good enough, you would be content with EP. I don't believe you would be content with it, I don't believe that it would ever meet your expectations. Specifically the expectation that you can run at near full power for an extended period of time. Maybe I'm wrong but you have strongly hinted at that expectation:

Originally Posted by CaptainRivet

...
But motorsailing or motoring longer distance just doesn't make sense at all with emotor and heavy batteries for a bluewater cruiser. And a diesel engine is also big security factor eg if you eg in a lee shore storm and have to motor against it....not gonna happen with an emotor.

If you are going to compare to diesel, be a little more realistic with it. Few if any monohulls that use a 30hp motor will have a 400l tank, that's 750lb of fuel plus tank weight. A 30hp motor would normally be considered appropriate for a 9-11m boat. By the time you get to 12-13m a 40-50hp motor is what is normally installed.

A 12m boat is going to have 150-200l of installed fuel tankage. A 10m boat is going to have more like 100l.

Yeah, you could carry Jerry cans on deck, but how many 12m boats are going to accept carrying 9-12 jerry cans of extra fuel?

OK so maybe your are thinking multi hull. 40' multis are going to use double 35-40hp motors and have installed tankage of 250-300l. How content are they going to be adding 200-300lb of fuel plus Jerry cans on deck?

Yeah, there are folks that will carry that. An there are other folks that install enough tankage to carry 400l. Not many of either though

[donradcliffe]

I just watched the latest Wynns video on their new HH44, where they are gushing about the 1200 watts of regen in 20 knots of wind at a TWA of 130 degrees. She is hosing down the deck with fresh water from the watermaker, loading the automatic dishwasher, and wants more power so she can turn on the aircon.

She would never be satisfied with an EP only system.

[donradcliffe]

Originally Posted by Adelie

I see it the other way. EP (Electric Propulsion) is not particularly good for day or weekend trips but much better suited to long offshore passages. For day and weekend trips one usually has a deadline to be home for work or family. If you are going offshore you shouldn't have a schedule so sitting and waiting for wind or sun shouldn't be that big an issue.

Jimmy Cornell's problem wasn't with the EP, it was with the regen. It's not clear if it didn't work as advertised or he didn't have his consumption under control or some of both. I suspect it was mostly lack of control of consumption coupled with regen underperforming somewhat. Whatever, he didn't take as much solar as he should have.
I have no info on what happened with the others. Lack of solar, failing to control consumption, inappropriate use expectations.

Certainly there are examples of boats such at Uma, Wisdom and Saoirse that have done significant passages and coastal sailing using just EP. I believe they have all installed significant solar capacity, have kept control of their house consumption and managed their expectations of what EP could provide them.

Living with EP successfully requires accepting the tradeoffs. If you don't want to accept them, don't but don't try to argue that it doesn't work because it wouldn't work for you.

When you do an offshore passage, your tankage limits motoring to a fraction of the passage length. When I deliver boats offshore, if the winds are good I only run the engine to charge the batteries. If the wind dies, I run the engine to get off the pond before the next storm or pirates show up. I rarely sit around waiting for a good wind to fill in.

When I did offshore passages on my boat, the solar, wind, and towing generator almost always kept up with my minimal consumption. I did make water when I ran the engine. But I never sat around waiting for wind like the old sailing ships.

Cornell's electrical system, both generation and consumption, was designed around OceanVolt's claims for regen. Their regen did not meet its design specs.

[JustMurph]

Originally Posted by Tupaia

There is a major problem with perceived power obtained from regen on fast light cats. It only takes a tiny amount of drag (regen) and you are no longer doing 200 plus mile days. I experimented with a max prop, locked in reverse and at 8 knots would have produced 4hp under load but reduced the sailing speed by 20%. I had shafts with belt drives so my losses would be higher that a modern electric pod but the drag from even a freewheeling propeller locked in reverse is significant. Also the design of a propulsion propeller is not the same as a regen propeller. Regen works on vehicles because of the need to slow down (brake) and the fact that there are hills on land. The whole idea of using regen to generate electricity is an anathema to a cat that is designed to sail "fast".

None of these systems can produce 3kW at 8 knots, so the 20% figure is misleading. Most of them aren't hitting over 1kW until you're doing around 10 knots. Most of the data I've seen suggests well under 10% loss of speed.

[CaptainRivet]

Originally Posted by Adelie

You imply that if all the parts of the system were good enough, you would be content with EP. I don't believe you would be content with it, I don't believe that it would ever meet your expectations. Specifically the expectation that you can run at near full power for an extended period of time. Maybe I'm wrong but you have strongly hinted at that expectation:



If you are going to compare to diesel, be a little more realistic with it. Few if any monohulls that use a 30hp motor will have a 400l tank, that's 750lb of fuel plus tank weight. A 30hp motor would normally be considered appropriate for a 9-11m boat. By the time you get to 12-13m a 40-50hp motor is what is normally installed.

A 12m boat is going to have 150-200l of installed fuel tankage. A 10m boat is going to have more like 100l.

Yeah, you could carry Jerry cans on deck, but how many 12m boats are going to accept carrying 9-12 jerry cans of extra fuel?

OK so maybe your are thinking multi hull. 40' multis are going to use double 35-40hp motors and have installed tankage of 250-300l. How content are they going to be adding 200-300lb of fuel plus Jerry cans on deck?

Yeah, there are folks that will carry that. An there are other folks that install enough tankage to carry 400l. Not many of either though

You are correct on monos, i should have said 50hp for 12-14m boats.

My 12m ketch had 550l tank, nearly all the 12-14m boats on my pontoon here in the canaries have 6x20l jerry cans strapped on deck, 3 each side.
Yes you are correct the 12-14m have 40 or 50hp engines but tankage is 300-400l, my buddy has dufour 44 which is a 12t mono with 50hp and 380l tank. The D2-50 is 80kg more then the 30hp and 0.5l/h more at 5kn then 30hp. I know because i have 2x50hp instead 2x30hp in my Lavezzi now. Monos have not enough space for solar and regen due to limited to hull speed is small, so hybrid the only way but with 60-80k option price for it not economical at all.
Multihulls: don't even try a 40ft mass condo, by far too heavy and will never work.
the HH44 has 2x30hp betas/hybrid as well as the mumbay48 has 2x30hp and also the Odyssey 48 is speced for 2x29hp Nanni due to spec sheets.
Outremer 45/48 has 2×30hp with 430l
All these are the best you can get to put emotors in and it still doesn't work for a bluewater cat. They are perfect for hybrid if the price comes down to half, otherwise its simply more economical to take 2x30hp engines.

the alibi 52 a friend bought has now 2x50hp with 700l tank installed by former 1st owner, a well known race sailor, was throwing out the emotors because it didn't work which was a 150k option down the drain...

EV market is collapsing, Ford and GM stopped production of EVs as the customers don't want them....chinas big ev market is a big fake with 100000 cars rotting on yards that where registered to fake boost the market....
Yes are several use cases EV and propulsion work well eg canal and ferry boats which are charged inbetween at the dock or little city cars. But for bluewater boats never.

[Tupaia]

Originally Posted by CaptainRivet

Multihulls: don't even try a 40ft mass condo, by far too heavy and will never work.
the HH44 has 2x30hp betas/hybrid as well as the mumbay48 has 2x30hp and also the Odyssey 48 is speced for 2x29hp Nanni due to spec sheets.
Outremer 45/48 has 2×30hp with 430l

This is exactly on point. To compete EV must be lighter and more economic and green.
I have 2x27hp Lombardini saildrives (141kg each), 4x65l fixed tanks and I carry 2x20l jugs for emergency when making a long passage. Motoring on one engine (normal state) unless anchoring or mooring.
Uses 1.86-2.1 l/h at 5kns a theoretical range of 750Nm instantly available day or night.
These engines can be bought off the shelf for $6400 each, double that for installation costs and it is about $25k
Weight 2x141kg (engines) + 80kg (extras) + 300kg (fuel) + 30kg (tanks) circa 700kg in total.
If coastal sailing chances are I will have about 60l in each side a weight saving of 180kg giving a total weight of just over 500kg and still giving a range of 300Nm.
I average about 90 hours per engine per year. So fuel burn is about 360l per annum ($360) oil and filter changes are at 125hours typically every 18months at $45 per engine put the annual figure at $420. An SUV uses about 2000l of fuel per annum.
EV just doesn't represent any benefit.

[Adelie]

Originally Posted by donradcliffe

When you do an offshore passage, your tankage limits motoring to a fraction of the passage length. When I deliver boats offshore, if the winds are good I only run the engine to charge the batteries. If the wind dies, I run the engine to get off the pond before the next storm or pirates show up. I rarely sit around waiting for a good wind to fill in.

When I did offshore passages on my boat, the solar, wind, and towing generator almost always kept up with my minimal consumption. I did make water when I ran the engine. But I never sat around waiting for wind like the old sailing ships.

Cornell's electrical system, both generation and consumption, was designed around OceanVolt's claims for regen. Their regen did not meet its design specs.

Cornell bought into marketing hype without significant first testing it himself. Nor did he provide redundant charging sources.

Regardless, it was conflating the specific problems of regen with the general limitations of Electric Propulsion.

[JustMurph]

Originally Posted by Tupaia

This is exactly on point. To compete EV must be lighter and more economic and green.
I have 2x27hp Lombardini saildrives (141kg each), 4x65l fixed tanks and I carry 2x20l jugs for emergency when making a long passage. Motoring on one engine (normal state) unless anchoring or mooring.
Uses 1.86-2.1 l/h at 5kns a theoretical range of 750Nm instantly available day or night.
These engines can be bought off the shelf for $6400 each, double that for installation costs and it is about $25k
Weight 2x141kg (engines) + 80kg (extras) + 300kg (fuel) + 30kg (tanks) circa 700kg in total.
If coastal sailing chances are I will have about 60l in each side a weight saving of 180kg giving a total weight of just over 500kg and still giving a range of 300Nm.
I average about 90 hours per engine per year. So fuel burn is about 360l per annum ($360) oil and filter changes are at 125hours typically every 18months at $45 per engine put the annual figure at $420. An SUV uses about 2000l of fuel per annum.
EV just doesn't represent any benefit.

The only set up that really makes sense in my mind, is an asymmetric parallel hybrid. Put a slightly larger, parallel hybrid diesel in one hull and an electric in the other. You get all of the EV advantages for short distance Electric motoring and regeneration while still having the diesels power and range. You save yourself the weight and maintenance of one less diesel engine, but do add some weight and complexity with the electric and batteries. And you have the advantage of very high current charging from the hybrid diesel.

[s/v Jedi]

We’re talking sailboats, right? The kind of boat you hoist sails and the wind moves the boat? They have auxiliary engines, for which electric is fine.

If you want to motor, buy a motorboat.

[Tupaia]

Originally Posted by s/v Jedi

We’re talking sailboats, right? The kind of boat you hoist sails and the wind moves the boat? They have auxiliary engines, for which electric is fine.

If you want to motor, buy a motorboat.

In an ideal world yes but circumstances mean that auxiliary power is needed when its needed and the need to charge electric makes it less than suitable.



Just look at the engine hours to see which boats actually sail. You have a sail boat how many engine hours have you recorded?

[s/v Jedi]

Originally Posted by Tupaia

In an ideal world yes but circumstances mean that auxiliary power is needed when its needed and the need to charge electric makes it less than suitable.

Just look at the engine hours to see which boats actually sail. You have a sail boat how many engine hours have you recorded?

Last passage was a couple months ago… I motored out of the marina and Port Canaveral, hoisted sails outside and cut the engine. 46 hours later I anchored under sail in the Abacos.

Yes, I had some calm periods… at some point the Gulf Stream even set me back a bit. But 46 hours to Green Turtle Cay is still fine for me.

So let’s say it was 45 minutes motoring.

[Tupaia]

Originally Posted by s/v Jedi

So let’s say it was 45 minutes motoring.

A passage that went to plan. But, my question was how long have you owned your boat and how many engines hours have you logged?