Oceanvolt Hybrid Motor

[Seaslug Caravan]

Originally Posted by BigBeakie

?

OK lets take a boat that something is known about, like Conrad Coleman's IMOCA 60 in the last Vendee Globe, OK?

...

Dear Mr BB, Have you considered that SD 15 Manufacturer may have been a sponsor. Could this taint the data?

Remember that Conrad Colemans electrical system caught fire during the race. This event could easily have ended tragically.

[44'cruisingcat]

Originally Posted by BigBeakie

Now, why would a fiercely competitive Vendee Globe racer want to use anything that would slow his boat down, even a bit???

This should be interesting....

Interesting, but quite easy to answer. Because he didn't want to use fossil fuels. He's a greenie. For instance, he doesn't eat meat because of the environmental impact of growing it.

But seriously, do you really believe you can extract several kilowatts and not slow the boat down "even a bit"? Really? Your believe that?

I've got this bridge you might be interested in buying. It's quite a bargain....

[Jim Cate]

BB, I know that wasn't directed at me, but I gotta reply...

There is simply no way to extract energy from the speed of the boat without affecting that speed. If you have found a way to do so, the folks at Physical Review await your learned paper describing the process. There may be an issue with peer review though...

Now, how much is the boat slowed down? I don't think we have the necessary data to determine that number. Your list of speeds vs power output are interesting and impressive, but they don't say that for, say, the 16 kts/4.4 kw relationship that without the drag of the regen the speed would have been somewhat higher. Exact amount? Who knows, but I suspect that it would vary depending upon sea state, point of sail and perhaps other factors.

Now as to why he reported not seeing a speed reduction... well, he does seem to have a relationship with the vendor, one that might well influence what he reported. I'm not accusing him of lying, but more of selective reporting. As a retired experimental scientist, I know full well how easy it is to select data that supports one's hypotheses. Remember if you will the cold fusion fiasco... I wouldn't think such things if his (and their) claims didn't fly in the face of physics. Lastly, boat speeds in sailing vessels are rarely steady. Surely you have noted that when you have been sailing. If one is trying to see small variations in speed when turning on the regen, it isn't all that easy to decide if that change was due to the drag or to a small natural change in speed. It would take some deliberate experimentation to reliably show such small changes; I rather doubt that this chap spent the time and effort to make such experiments during the heat of the race.

As to your last query... I'm sure that he needed the electrical energy, and that's why he put up with whatever speed reduction that resulted. There is no electrical generation system that produces energy with no cost to the boat. Gensets and their fuel add weight, solar panels add windage, hamsters on treadmills require feeding... every thing has a cost.The regeneration system may indeed be the best answer for a VG boat, but it can't supply the power with zero cost in performance.

Your enthusiasm is laudable; your unwillingness to heed physics not so much.

Jim

[Seaslug Caravan]

By the way Conrad Coleman was way back in 16 th position at the finish with rig issues. However he was 10th before this issue.

Whats the point in building a performance boat and then dragging the electrical equivalent of a sea anchor around.

[transmitterdan]

There would be no need for the IMOCA boat to "estimate" how much the regen slowed the boat. All one has to do is kill the field and let the prop free wheel and record the change in speed. So if the racer says he can only estimate the slowing effect it sounds fishy.

He has to run the regen to have any power so there may be competitive or philosophical reasons he does not want to give hard data. But not because it is hard to measure.

[StuM]

Originally Posted by transmitterdan

there may be competitive or philosophical reasons he does not want to give hard data.

Not to mention commercial/sponsorship reasons.

[StuM]

Originally Posted by Jim Cate

BB, I know that wasn't directed at me, but I gotta reply...

Thanks Jim. Comprehensive and lucid argument as always.

[Seaslug Caravan]

Originally Posted by BigBeakie

Now, why would a fiercely competitive Vendee Globe racer want to use anything that would slow his boat down, even a bit???

This should be interesting....

BB, its all to do with the sponsorship $$.

Green, low carbon footprint, was his angle.

Winning gets media coverage and pleases the sponsors, only one can win so the also rans need a difference to stand out from the losers.

At one time the sponsors were happy for you to capsize if you couldn't win, that certainly got you/them on the front page. I suspect times have changed.

Regenerative charging is great for trains. Not so great for performance sailboats.

[BigBeakie]

Well Ok Gentlemen. Did you ever see me say that the OV SD15 regen had no effect on boatspeed? Ever? No, you did not.So why are you taking that tack, if you'll pardon the pun.

I freely concede your (collective) point that using regen slows a boat. It slows it down by such a small amount, that it is effectively hard to determine. Therefore of no consequence. That is what has been reported to me by several OV users, and it is just not credible that they are all lying, now is it?

Now, you all are stating and/or implying that it must be a terrible drag on the boat, my goodness like "dragging a sea anchor". Otherwise why would you even be raising it?

But none of you would take a stab at quantifying it, now did you? And that would be because you (collectively) have no bloody idea.

So unless you can illuminate the discussion , or refute Colemans observation that it slowed his boat maybe a quarter of a knot, or the observers on Kato recently that it made no detectable difference, then I'm afraid we'll have to consider the possibility that you (collectively) are wrong. Ipso facto quid est demonstratum, gentlemen. Consider the evidence and first hand reports.

And Jim, I know you don't have a dog in the fight, but I'm a retired research scientist as well, so I know about data quality and experimental bias, and confirmation bias. And yes, I did physics to the B.Sc. level, so please stop saying EP transgresses the laws of the universe for cryin' out loud.

[svseachange]

Oh that Kato. Nice looking boat that goes about a zillion times faster than us. If they lost a 1/2 a knot to generate power they probably wouldn't notice.

[transmitterdan]

BB,

If you are a physics major please tell us how the units of measure for thrust and power are equivalent.

[Seaslug Caravan]

BB, this thread is fun.

There appears to be very little accurate material on yacht regenative charging drag.

The drag between fixed and feathering props on a standard installation would be a good starting point.


Have you considered asking people what difference changing from a fixed propellor to a folding or feathering prop makes to their boat speed under sail?

Obviously significant cause even the long keel slugs tried to line their fixed props up with the deadwood.

A quick look at Seahawk: Customer Feedback on Autostream Self Feathering & Slipstream Folding Propellers - Catamarans

Turns up some customer feedback.

Like.......
Here is what Alan Jones had to say aftyer fitting Autostream feathering props to his catamaran
View Full Article
"...I estimate about half a knot more boat speed under power and about 3-4 knots under sail.

I know when I leave my outboard in the water I easily loose 1 knot at 6. 16% drop??

Now put said outboard in gear (equivalent to charger ON) and really see the boatspeed drop.

I get the impression BB that you don't want to know the warts and all truth.

[BigBeakie]

Originally Posted by transmitterdan

BB,

If you are a physics major please tell us how the units of measure for thrust and power are equivalent.

Aha, that could be your problem, you don't read carefully.

I never said I majored in physics, I said that I took physics in a B.Sc., I majored in Biochem and Microbiology.

But I'm sure you are an absolute whiz and can easily work out for us how to predict how much boatspeed will be lost by regen.

So how much boatspeed loss was Coleman lying about?

[44'cruisingcat]

So, fit 10 of these magical drives to a boat. Have one working on propulsion, 15 kw pushing us at 8 knots.

The other 9 on regen, producing a couple of kilowatts each. And not slowing the boat down even a tiny bit.

Perpetual motion.

Well, it seems some people believe....

[44'cruisingcat]

Yet back in the real world, f1 cars, trains, hybrid road cars etc actually have regenerative BRAKING.