E-motion rudder drive...thoughts?

[Binarysailor]

6.1 knots, 3 hour recharge. Is this the electric motor we have been waiting for? Honestly, I have very little experience in this area. But this article looked interesting.

Is the E-Motion Rudder Drive a Revolution in Yachting? >> Scuttlebutt Sailing News

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[SV DestinyAscen]

Not really. Torqueeos unique contribution is the efficiency of its motors - their batteries aren't particularly good, and looks like they basically took their smaller outboard and made it into a rudder form factor. Not sure how that's good thing because the benefit of outboards was being able to take it out of the water, light and easy to replace... now its a saildrive only worse - stuck to the rudder. Once you buy in you have no other options.

[denverd0n]

What I notice is that the underwater view is clearly a CGI graphic--not an actual picture. And they don't seem to have any actual, underwater videos of this thing in operation. So, I'm guessing that at this point it is just vaporware.

Never mind the fact that I really don't want that thing hanging on my rudder all the time. Folding props sometimes don't fold so well. That's bad enough when it is on a shaft under your boat. What sort of havoc will it wreak hanging on the back of your rudder like that!?!

It is an interesting idea, and I like to see people thinking outside the box. But I will hold off until it has been around long enough for someone ELSE to be the guinea pig!

[deepthought]

I have had very bad luck with torqeedo so would stay away from it. Also there US customer service is very bad. EU is a bit better. But there products while the ideas are good the quality is bad. I have had almost 8 of there motors in the past all where failures. I dont think any of there developer have been out side of a testing environment or a pretty little pond.

When I think Torqeedo I think of how my boat almost burnt.

[myocean]

Originally Posted by deepthought

I have had very bad luck with torqeedo so would stay away from it.

Well, they went through quite a learning curve as it is common for new technology. Seems you are one of the poor guys who suffered quite a bit. This was probably about 3 years back in time, right?

Originally Posted by denverd0n

So, I'm guessing that at this point it is just vaporware.

But it has been shown on the Boat Show in Hamburg, right?


Hanse Hanse did not fake the "test-drive" video. There was probably just not enough time before going public to produce nice looking underwater videos in the turbid, cold German waters.

[StuM]

4kW (5HP) motor? OK for gettting a 30ft 4.7 tonne boat in and out of a marina in calm conditions, but that's about it.

It's probably worth noting that they are replacing the standard 8.6kW(11.8 HP) engine with one less than half the power.

[myocean]

Originally Posted by StuM

4kW (5HP) motor? OK for gettting a 30ft 4.7 tonne boat in and out of a marina in calm conditions, but that's about it.

It's probably worth noting that they are replacing the standard 8.6kW(11.8 HP) engine with one less than half the power.

The (Yanmar?) diesel engine you mention, with the proposed prop, reaches 4 kW prop shaft power at 3000 rpm only. See attachment.
So it needs to be operated at full rpm of 3600 to reach the maximum power of 8.6 kW.
I would say such a diesel, limited to a maximum of 3000 rpm, is good for much, much more than "in and out of a marina in calm conditions". And so is the electric drive. Just without so much noise, exahust, maintenance, oil, fuel, ....


Oh, and I nearly forgot: Certainly even no seacock for water cooling and in return the superb maneuverability.

[DeepFrz]

myocean, just wondering if you have any vested interest in this or similar product that you should declare?

[myocean]

Originally Posted by DeepFrz

you have any vested interest in this or similar product that you should declare?

Yes, I am with Torqeedo, as said at another occasion before.
(Topic "Re: Electric Outboard Motor")

Originally Posted by myocean

OK, guys, this subject convinced me and so, since about 10 days, I am working for the company with the T.
Since today I am even more convinced: After testing the boat shown below with the new 10 kW outboard, I am fascinated by
the astonishingly pleasant absence of noise. It feels like this is the future, despite of the disadvantages discussed before.

Practically it's indeed, as said, just "the sound of the wind and splashing of the wake" which you hear while speeding around.

I think electric motors do not make sense in any occasion but for some boats and some use cases they they are a very good idea.

In this case, by the way, the weight advantage of the electric solution is more than 100 kg if you include service battery, starter battery, oil, cooling water and a diesel tank with 25 l of fuel. (with no diesel just 21 kg less advantage)

[StuM]

Originally Posted by myocean

The (Yanmar?) diesel engine you mention, with the proposed prop, reaches 4 kW prop shaft power at 3000 rpm only. See attachment.

Don't know what engine that power curve is from, but it's not the 11.6 HP that Hanse quote as the standard.

So it needs to be operated at full rpm of 3600 to reach the maximum power of 8.6 kW.
I would say such a diesel, limited to a maximum of 3000 rpm, is good for much, much more than "in and out of a marina in calm conditions".

Even limited to 3000 RPM, an 11.6HP diesel will be generating a lot more than the maximum 5HP which the E-motion apparently puts out. So you are correct, such a diesel is good for more. No one disputes that.

And so is the electric drive. ...

Sigh! Here we go again! Good old "magic electric HP" where somehow less HP gives just as much power if it is derived from electricity.

[myocean]

Originally Posted by StuM

Sigh! Here we go again! Good old "magic electric HP" where somehow less HP gives just as much power if it is derived from electricity.

I think you should at least LOOK at the propellor curve diagram and realize that with this, the diesel at 3000 rpm is good for not more than 4 kW. (because of the prop characteristics)
Have you seen this? There is no magic.

Certainly people COULD use another prop which allows at 3000 rpm to use the full available shaft power of 6 kW. But nobody does this because it would waste the rest of the theoretical max. power.

[StuM]

Originally Posted by myocean

I think you should at least LOOK at the propellor curve diagram and realize that with this, the diesel at 3000 rpm is good for not more than 4 kW. (because of the prop characteristics)
Have you seen this? There is no magic.

Certainly people COULD use another prop which allows at 3000 rpm to use the full available shaft power of 6 kW. But nobody does this because it would waste the rest of the theoretical max. power.

I repeat, that power curve is NOT for the engine which is standard on the Hanse. It is a much less powerful engine and continuing to use it once that has been pointed out is deceptive to say the least.

The actual figures for the standard engine are more like this:
11.8hp Volvo Penta D1-13
RPM PROP HP

1800 2 (1.5kW)

2600 6.2 (4.6kW)

2800 7.9 (5.9kW)

3200 11.8 (8.6kW)

We can extrapolate from those figures that you reach a power output equal to the maximum output of the E-motion at around 2400 rpm or 75% of WOT and are still using less than 50% of your available power.

[myocean]

Originally Posted by StuM

I repeat, that power curve is NOT for the engine which is standard on the Hanse. It is a much less powerful engine

Oh, yes, you are correct. I missed your first statement about this, sorry. This was not my intention.

Lets look further: On flat water this boat needs for 5 knots a power of 2.1 kW. 1.1 kW are sufficient for 4 knots (both measured with the lighter electric system installed).
So if you assume with wind and waves you need factor 2 or 3 more power (sea margin) it can still go with quite a bit more than 4 knots.

This is not completely unpractical to use but for may people it is absolutely fine
- in return for all the other benefits.
Don't yo think so?

[denverd0n]

Originally Posted by myocean

This is not completely unpractical to use but for may people it is absolutely fine
- in return for all the other benefits.
Don't yo think so?

I can't speak for Stu, but for me the answer to that question is very simple: NO!