Oceanvolt Hybrid Motor

[BigBeakie]

Originally Posted by Blue Skye

Don't give in BB! I've been away from the forum for a while, sporadically checking in. Was wondering if you ever decided to build a FF46

Hi Skye,

No, we are building the first FreeFlow 50, i.e. hull #1 in a new production design.

[Blue Skye]

Congrats! Sorry for thread drift, but do you have a website with specs and updates during build process?

Back to our regularly scheduled programming

[BigBeakie]

Originally Posted by Blue Skye

Congrats! Sorry for thread drift, but do you have a website with specs and updates during build process?

Back to our regularly scheduled programming

Thanks, it is an exciting boat, and somewhat unique. No sense doing what everybody else is doing

That info is all coming in the not too distant future.

[44'cruisingcat]

Originally Posted by BigBeakie

"YOU CAN'T BE SERIOUS!"

Conrad Coleman in the Vendee Globe didn't think it was "pretty much useless", did he?

So you just buy the motor, fit it to your boat and off you go?

Doesn't need batteries, or a genset or anything?

An electric motor that doesn't need electricity. That IS impressive.

[44'cruisingcat]

Originally Posted by BigBeakie

No sense doing what everybody else is doing :thumb.

Heck no! Where's the sense in doing something that's known and proven to work? Especially when you can spend 2 - 3 times as much on something that MIGHT work!

[BigBeakie]

Originally Posted by 44'cruisingcat

Heck no! Where's the sense in doing something that's known and proven to work? Especially when you can spend 2 - 3 times as much on something that MIGHT work!

I wasn't actually referring to propulsion, but a few other things that will be different.

[BigBeakie]

Originally Posted by 44'cruisingcat

So you just buy the motor, fit it to your boat and off you go?

Doesn't need batteries, or a genset or anything?

An electric motor that doesn't need electricity. That IS impressive.

Sometimes 44, you can be a silly fellow. And then sometimes, you can make worthwhile contributions. Sometimes.

[44'cruisingcat]

Instead of personal abuse, how about answering the question? After spending your $15K, do you have an operable, useful propulsion system or not?

[Seaslug Caravan]

Originally Posted by BigBeakie

At 12 knots there will be about 4.5kW PER MOTOR !

Out of interest Mr BB can you tell us how much drag is exerted by the leg and the prop at 12 knots.

If you are generating 4.5 KW . approx 6 HP, surely the drag would be similar to running a 6 hp outboard in reverse the whole time , OH, plus the drag of the leg and inefficiencies , so maybe 12 HP in reverse. Now if thats a 12 HP electric outboard, then what?? thats equivalent to a 20 HP petrol OB.

AND thats only for one motor.

Or doesn't it work like that?

I'm thinking , whilst the AC units will be keeping the boat nice and cool with this abundance of power, the passage times may increase by a "tad".

Infact it may be quicker to reverse to your destination.

[BigBeakie]

Originally Posted by Seaslug Caravan

Out of interest Mr BB can you tell us how much drag is exerted by the leg and the prop at 12 knots.

If you are generating 4.5 KW . approx 6 HP, surely the drag would be similar to running a 6 hp outboard in reverse the whole time , OH, plus the drag of the leg and inefficiencies , so maybe 12 HP in reverse. Now if thats a 12 HP electric outboard, then what?? thats equivalent to a 20 HP petrol OB.

AND thats only for one motor.

Or doesn't it work like that?

I'm thinking , whilst the AC units will be keeping the boat nice and cool with this abundance of power, the passage times may increase by a "tad".

Infact it may be quicker to reverse to your destination.

No, it doesn't work like that. I can tell you that both Kato and the Vendee Globe boat could not detect any definite speed change when the SD15 is put into regen mode. Coeman said a couple of times at slower speeds (for him) he thought maybe there was 0.25 knot in it, but it was a maybe.

It is not putting the prop in reverse.

[StuM]

Originally Posted by BigBeakie

No, it doesn't work like that. I can tell you that both Kato and the Vendee Globe boat could not detect any definite speed change when the SD15 is put into regen mode. Coeman said a couple of times at slower speeds (for him) he thought maybe there was 0.25 knot in it, but it was a maybe.

It is not putting the prop in reverse.

TANSTAAFL.

It is an epistemic impossibility to take 4.5kW out a boat's motion through the water without imposing at least an equivalent drag regardless of what method you use. If it were otherwise, you would have a perpetual motion machine of the first kind.

[44'cruisingcat]

Originally Posted by BigBeakie

Thrust at full power speed, depends on the boat (hull resistance) what that speed value is.

It also depends greatly on the pitch and diameter of the propeller. Ie tugs have tremendous thrust, but don't go very fast considering the amount of power they have.

[44'cruisingcat]

Originally Posted by StuM

TANSTAAFL.

It is an epistemic impossibility to take 4.5kW out a boat's motion through the water without imposing at least an equivalent drag regardless of what method you use. If it were otherwise, you would have a perpetual motion machine of the first kind.

Apparently, a 15 kw diesel can power a 10kw generator, which can power a 10 kw electric motor, which is equivalent to a 20. kw diesel.

So why not use a 10 kw electric motor to power a 20 kw generator, which could run both the generator motor Plus a 10 kw propulsion motor whilst using zero fuel.

[BigBeakie]

Originally Posted by StuM

TANSTAAFL.

It is an epistemic impossibility to take 4.5kW out a boat's motion through the water without imposing at least an equivalent drag regardless of what method you use. If it were otherwise, you would have a perpetual motion machine of the first kind.

So Stu, how much would that slow down the boat? Depends on the boat, right?

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

Here's the specs for the boat:
Length: 18.28m
Beam: 5.6m
Draft: 4.5m
Displacement: 8.5 Ton

And here are some datapoints of boatspeed and corresponding power from the SD15 regen logged during the race:

11 knots > 2.8 kW
15 knots > 3.3 kW
16 knots > 4.4 kW
18 knots > 5.5 kW Note that these were using the old prop not the new Servoprop, which is even better.

Could you enlighten us on your estimate of how much his boat was slowed down?

Could you suggest a reason he reported not seeing your epistemically certain drag on such a sophisticated race boat? You would think he could monitor his speed quite accurately, no?

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....

[44'cruisingcat]

Did he win?