Electric drive conversion

[bill]

Hi everyone,
I want to let you all know that I managed to convert a diesel drive marieholm to electric drive and the results are amazing!
The yacht is not mine; it belongs to a good friend. End of last year I joked about converting his yacht to electric as he drives a Tesla and is very much into renewables! He thought it would be a great idea... and here we are with an electric Marieholm launched two days ago!
The system we went for is a 5Kw Oceanvolt with 8 valence LiFPO4 batteries. I did the conversion myself an I am an engineer and I have lots of information if any of you are interested so if you have any questions feel free to ask!
Here are a few pictures:

[johan swe-1870]

That's an interesting solution with a modern motor type! I think many of the members here like to know more about that.

Whats the battery specification? Number of batteries, energy capacity, weight.
How many amps does it need for charging?
Whats the boat speed? Wich distance can it make?

[bill]

Hi Johan,

The batteries are 8 off valence LiFPO4 12V 130 Ah arranged in two parallel strings of 4 batteries in series. The useful energy of this arrangement is about 10KWh. The weight of the batteries is about 20Kg each. I don’t have measured consumption figures yet but here is what I achieved on Monday: going from the launch slip to the marina we were cruising at about 4 Kn using about 300W. The onboard control system was projecting a motoring range of around 40 hrs ( its the best measure as the actual distance covered would depend on tides, currents wind direction and so on). So depending on condition this can give a range of 35-50 Miles at that cruising speed. As we are using a high pitch propeller, this drops the consumption down and makes for a much more responsive vessel, even going astern! As for charging, the charger is using standard shore power (less than 12A). If the projected range is correct, I think we would only need to charge 2-3 times during the season as motor use is only to get sailing from the mooring and return when sails are down! And it’s so quiet!!

[Crazy Mary IF2670]

Hi,

Congratulations, it sounds like a dream! I have been checking the pod motors to laminate on the rudder of my IF, I have seen that some of them can generate electricity while sailing (propellor turns the motor other way around to generate electricity), do you have such function? I also find out that with empty batteries and proper solar panels you can still move even slow...

If you have such a huge range you can reduce the number of batteries (I believe they are like another man on board).
Thks,

[bill]

Hi,

Congratulations, it sounds like a dream! I have been checking the pod motors to laminate on the rudder of my IF, I have seen that some of them can generate electricity while sailing (propellor turns the motor other way around to generate electricity), do you have such function? I also find out that with empty batteries and proper solar panels you can still move even slow...

If you have such a huge range you can reduce the number of batteries (I believe they are like another man on board).
Thks,

Hi

It’s interesting that you are considering the rudder electric propulsion as I am putting a system together for my next project! I think this a much better solution than the outboard hanging over the stern and is easily fitted to any IF with out a factory fitted engine.
Regeneration is possible but very much depends on the hull speed.. need to be consistently sailing at over 5 Kn to have any meaningful charging capability. PV panels are better but bulky and inconsistent. Wind gen is better. This is one of the reasons I went for the extra batteries. It doubles the range, halfs the charging cycles, reduces range anxiety(!) and although it doubles the battery weight I think it’s good weight as it’s low and along the centreline of the yacht.

Which motor are you considering?

[Crazy Mary IF2670]

Hi,

It is good to hear that. First I have checked the minnkota and torquedoo, especially torquedoo get a lot of awards and they worked with Hanse 315 for the electric one, I found them a bit expensive and they really do not have a commercialized solution for the rudder, I think they did the rudder-drive only for Hanse, there is nothing in their website. One idea it to get a transom model and part it out and convert it which I would enjoy to do so.


In one of the exhibitions I have found a German company that was providing solutions but at that time I didn't have the Marieholm and I am still trying to find their contact. There are couple of the also belmarine, e-tech, oceanvolt etc...

well folkboat company have the patent of it;

http://www.folkboat.de/#

I did not check if they can only sell the pod and electronics... their supplier is http://www.kraeutler.at/en/motors/boat-motors/ but they do not have rudder drive on website....

http://www.ghboats.com/options/accessor ... ric-motor/
they have it but does not look like a professional company... but what I see on photos is rather simple solution....

What are you planning to do?
Which motor will you use?

Besides that submersible fixed pods are an option but they will slow us down in sailing and we need to drill the hull of a 40 years old boat..... so far folkboat.de made the best one with folding propellor... I am worried their price might cost as much as an IF...
Thx

[Joel235]

That looks like a very interesting build, I must say. Good work on an interesting project. Where is the boat located?

I've also been musing about this conversion, probably following the example on folkboat.de with the rudder-mounted gland motor and folding prop. I sent a query to krautler some time ago, but never did hear back with a quote for the motor. I'm also concerned that it may cost as much as the boat (so I was intending to wait until my current outboard reached the end of it's life before committing, or maybe until batteries get vastly xx).

What are your thoughts on having solar panels to provide power, and allow greatly extended range? It seems to me that if you're only running the motor for an hour a day (in/out of anchorage) at 300W, you wouldn't need much panel area to get 'unlimited' usage. Even if you didn't have 'unlimited' range, you could definitely generate enough to greatly extend your range over long nordic summer days.

Also, what prop did you use? I'd be curious to see how changing to a folding prop would affect motoring efficiency vs sailing efficiency.

[bill]

Hi,

It is good to hear that. First I have checked the minnkota and torquedoo, especially torquedoo get a lot of awards and they worked with Hanse 315 for the electric one, I found them a bit expensive and they really do not have a commercialized solution for the rudder, I think they did the rudder-drive only for Hanse, there is nothing in their website. One idea it to get a transom model and part it out and convert it which I would enjoy to do so.


In one of the exhibitions I have found a German company that was providing solutions but at that time I didn't have the Marieholm and I am still trying to find their contact. There are couple of the also belmarine, e-tech, oceanvolt etc...

well folkboat company have the patent of it;

http://www.folkboat.de/#

I did not check if they can only sell the pod and electronics... their supplier is http://www.kraeutler.at/en/motors/boat-motors/ but they do not have rudder drive on website....

http://www.ghboats.com/options/accessor ... ric-motor/
they have it but does not look like a professional company... but what I see on photos is rather simple solution....

What are you planning to do?
Which motor will you use?

Besides that submersible fixed pods are an option but they will slow us down in sailing and we need to drill the hull of a 40 years old boat..... so far folkboat.de made the best one with folding propellor... I am worried their price might cost as much as an IF...
Thx

hi
I have looked at all of the above but settled on the torqeedo pod drive as its quite compact and it seems the only one that is compatible with salt water. its not the xx option but I think its probably the best! the biggest headache is fitting it on the rudder and sealing the cables to the pod whilst making the whole thing dry and serviceable. there is no folding prop option with this pod so might have to do some work on that... need to find a donor first...!

[Crazy Mary IF2670]

I think if you can make a rudder which is a good solution for you to work on. then you can find a donour to install your rudder to test, I believe rudder can be replaced while the boat is in the water. I think it is much easier than asking someone to cut his rudder

[bill]

That looks like a very interesting build, I must say. Good work on an interesting project. Where is the boat located?

I've also been musing about this conversion, probably following the example on folkboat.de with the rudder-mounted gland motor and folding prop. I sent a query to krautler some time ago, but never did hear back with a quote for the motor. I'm also concerned that it may cost as much as the boat (so I was intending to wait until my current outboard reached the end of it's life before committing, or maybe until batteries get vastly xx).

What are your thoughts on having solar panels to provide power, and allow greatly extended range? It seems to me that if you're only running the motor for an hour a day (in/out of anchorage) at 300W, you wouldn't need much panel area to get 'unlimited' usage. Even if you didn't have 'unlimited' range, you could definitely generate enough to greatly extend your range over long nordic summer days.

Also, what prop did you use? I'd be curious to see how changing to a folding prop would affect motoring efficiency vs sailing efficiency.

hi
The boat is based in Falmouth, UK. it was very interesting indeed. the battery tray was the most challenging as I was aiming to keep the weight low on the boat so as not to effect the sailing. The fact that this was originally a motored IF made it easier.
Problem with Krautler motors is they are not suitable for salt water.
Assuming you mean solar panels to charge the propulsion batteries and not driving the motor direct, they work but they are quite bulky and take quite a lot of space, which is at a premium on these boats. I think wind generators would be better as you wouldn't be out sailing if wasn't windy where as you would if it was cloudy!
Used a special gori folding prop for electric motors which has a higher pitch. I haven't made any measurements to assess the differences with the fixed prop. I have heard figures of up to 2 knots but I think that's more likely to be on a fin keel rather than a long keel. I would like to do a hull speed graph at some point but i need to find someone to tow me!

[bill]

I think if you can make a rudder which is a good solution for you to work on. then you can find a donour to install your rudder to test, I believe rudder can be replaced while the boat is in the water. I think it is much easier than asking someone to cut his rudder

that is exactly what I am planning to do! for me, making a rudder is neither easy or cheep! As far as I know replacing the rudder in the water is not possible so I would be interested to hear how its done. Do the motored an non motored hulls have the same shape rudder? except the prop cut out of course!!

[bill]

I think if you can make a rudder which is a good solution for you to work on. then you can find a donour to install your rudder to test, I believe rudder can be replaced while the boat is in the water. I think it is much easier than asking someone to cut his rudder

that is exactly what I am planning to do! for me, making a rudder is neither easy or cheep! As far as I know replacing the rudder in the water is not possible so I would be interested to hear how its done. Do the motored an non motored hulls have the same shape rudder? except the prop cut out of course!!

Thinking about it.... is there a proper drawing of the rudder anywhere? that would be so helpful!!

[johan swe-1870]

There's a drawing of the rudder in the class rule drawings.

[bill]

There's a drawing of the rudder in the class rule drawings.

That’s great! Thanks for the pointer!
The drawing seems to suggest the rudder is tapered from 39mm forward to 10 aft. Am I correct or is this the drawing of the metal insert of the rudder?

[maja]

Yes, you are correct, tapered from about 40 mm (fwd edge) to minimum 10 mm (aft edge).
Class rules defines the shape, construction is free.
Not all rudders have metal inserts.