Oceanvolt Servoprop regen tested by UMA

[mglonnro]

Originally Posted by tp12

Sure, it's interesting I agree.

In the multi forum, though, aren't multi applications more interesting? They are to me, at least. Ok, I confess to being focused on the performance end of the multi spectrum. Boats trading accommodations and payload for light weight and speed

Performance multihulls, yes! But I also want the performance multihull to sail beautifully in 4-5 knots of wind, and I'm worried about the impact of the propellers vs folding ones. (Hopefully, the impact will be "insignificant" there as well.)

If I'd want to travel using as little diesel as possible (ie not starting the "hybrid" genset), being able to sail in really low wind conditions would be important as well.

[mglonnro]

Originally Posted by tp12

You've reminded me of a question I had myself during the video - pinching? Is he describing pointing as high maintaining some speed as you can as pinching? I'm thinking pinching is the first flutter at the luff and losing drive? What's his understanding bearing in mind he's not a racing sailor

I would have thought he'd be wanting to obtain data for close hauled and not pinching; hence my wondering on his definition of pinching.

Oh and I thought I should type pinching one time - pinching...

Pinching

Also, in the graph they are "pinching" doing 7 knots with a Pearson 36. Seems fast, so I assume he indeed means close-hauled (or even a bit down from that)!

[tp12]

Originally Posted by mglonnro

Performance multihulls, yes! But I also want the performance multihull to sail beautifully in 4-5 knots of wind, and I'm worried about the impact of the propellers vs folding ones. (Hopefully, the impact will be "insignificant" there as well.)

If I'd want to travel using as little diesel as possible (ie not starting the "hybrid" genset), being able to sail in really low wind conditions would be important as well.

We're in furious agreement. With less mass the force will be less and therefore maintaining regen will be difficult but so resistance will also be less given the hulls. It's all very complex

A good lightwind sail inventory will still be important from a power generation viewpoint along with sailing performance generally, sailor engagement, passage times... I digress

Performance multis are OBVIOUSLY the way forward

[NaClyDog]

Originally Posted by tp12

We're in furious agreement. With less mass the force will be less and therefore maintaining regen will be difficult but so resistance will also be less given the hulls. It's all very complex

A good lightwind sail inventory will still be important from a power generation viewpoint along with sailing performance generally, sailor engagement, passage times... I digress

Performance multis are OBVIOUSLY the way forward

If only the Elcano Challenge had been released to youtube you would have all the data you need. Unless an Outremer 4X isn't high performance enough I guess.

[seandepagnier]

Originally Posted by Paul L

So how many watts are generated per 0.1 nm of drag?

Originally Posted by tkeithlu

It will propell the boat at a smaller fraction of a knot for the same distance/time. Any other outcome would be a perpetual motion machine.

Shows a fundamental lack of understanding of how this works.

Originally Posted by BillKny

I don't know where you are getting your prices from, but they are WAY, WAY out of line, unless those mechanics in CT make more than lawyers....

The ocean volt system is a ripoff. They are being capitalists about it and any claim that they are making these for any other reason (such as environment) other than to maximize profits is false. Electric motors don't cost that much and oceanvolt systems are not efficient. They are like tesla for boat. Looks and acts with performance of combustion engine but at ridiculous price and overall poor efficiency compared to proven alternatives.

I know someone who just repowered a 40 foot boat with a new Beta engine for about $20K all up.

How much does "someone" get from regen from a beta engine?

Originally Posted by steffan

This might be a dumb question on my part regarding the physics: If your sails are trying to power you past hull speed, and that extra energy they could be providing is lost in the drag that keeps you at hull speed... couldn't you potentially capture some of that energy that would otherwise be lost to drag via regen, effectively paying for it by bringing speed back down to hull speed?

It is not dumb, because yes, near hull speed you can capture energy via regen with minimal loss in boat speed. The same amount of energy captured from 0.1 knot loss in speed can then in calm conditions can push the boat a few knots.

Now, this oceanvolt setup has a few glaring issues:
1) price
2) turbine is way too small. It should be larger so it can generate a lot more power. The variable pitch would let you adjust the drag vs power. The propeller is also too small to be efficient in propulsion at any speed.
3) limited camber. It is impossible to have a propeller efficient at both propulsion and regeneration made out of bronze because you need both variable pitch and variable camber. The only way to maximize efficiency in both cases is to use a separate turbine for generation. They refuse to acknowledge this in the video and fail to explain it. So there is a compromise and the result is less power for the amount of drag.

[s/v Jedi]

Originally Posted by mglonnro

A screencap of the bar chart they showed:

Attachment 245367

That looks suspiciously like meaningful data! Must be misleading false data, I bet they got that regen capable drive for free!

[Boatyarddog]

Originally Posted by NaClyDog

Is it trivial though? What may be trivial for you may not be for someone else. Trivial is subjective.


Actual and verifiable numbers would allow people to make their own determination of what is and isn't acceptable.

Can't be anything but trivial....it's a cruiser, sailing, free wind, what
problem could a half knot of drag cause to a cruiser.

I'm sure someone could think of something.... But?
SV Cloud Duster

[tp12]

Originally Posted by NaClyDog

If only the Elcano Challenge had been released to youtube you would have all the data you need. Unless an Outremer 4X isn't high performance enough I guess.

Yeah a real shame. The 4x is a performance boat, for sure. It might not be as far to the right on the spectrum as some of the kit boats and so on but it would be a valuable data point and I'd love to see it, definitely.

[NaClyDog]

Originally Posted by tp12

Yeah a real shame. The 4x is a performance boat, for sure. It might not be as far to the right on the spectrum as some of the kit boats and so on but it would be a valuable data point and I'd love to see it, definitely.

Really, even though it was a colossal failure and they had to turn around shortly after leaving because of... wait for it... power regeneration issues with Oceanvolt motors?


Real life and what you see on the internets are rarely the same.

[vpbarkley]

I watched the whole video. Impressive regen. But, sail drives have problems enough with water entry, corrosion and required maintenance. Add to that a servo motor and a variable pitch prop. This looks like a system for a nuclear powered sub. It's way too complicated for me.

[BillKny]

What's REALLY trivial here is generating 300 Watts and thinking you are going to go push the boat anywhere with that.

On my boat that's my normal house load when I am sailing! It would barely keep up with my usual usage!

And here is the REAL kicker, on my boat a prop shaft alternator was a builder option 30 years ago, and they made about 300 watts at 7.5 knots, and that was using a standard prop, and a field coil alternator.

So if you think this is some how "special and new" you are have been mislead.

[tp12]

Originally Posted by NaClyDog

Really, even though it was a colossal failure and they had to turn around shortly after leaving because of... wait for it... power regeneration issues with Oceanvolt motors?


Real life and what you see on the internets are rarely the same.

I don't know the use case you're talking about.

I can speak to the 4x design which is what my comments are about

[tp12]

Originally Posted by BillKny

And here is the REAL kicker, on my boat a prop shaft alternator was a builder option 30 years ago, and they made about 300 watts at 7.5 knots, and that was using a standard prop, and a field coil alternator.

Really? Got any data for that?

[NaClyDog]

Originally Posted by tp12

I don't know the use case you're talking about.

I can speak to the 4x design which is what my comments are about

No use case. Real life case.


https://www.yachtingmonthly.com/news...-on-hold-76722

[tp12]

Originally Posted by vpbarkley

I watched the whole video. Impressive regen. But, sail drives have problems enough with water entry, corrosion and required maintenance. Add to that a servo motor and a variable pitch prop. This looks like a system for a nuclear powered sub. It's way too complicated for me.

The complication argument I think is valid if you retain other systems. If you think in terms of reducing types of fuel carried on board and therefore reducing overall system complexity on board what's better - one more complex system with redundancy built in or multiple simple systems? IMO the first is more simple not to mention reducing the requirements for cruisers to find fuel types in various locations