Replace Diesel with electric engine

[mdenize]

Originally Posted by Ken Fry

For example, with a very limited budget, one could provide energy for lights, galley, refrigerator, electronics and motoring, without even taking advantage of sailing regen, as these folks do. Kudos for a nicely done explanation:

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They use a lot of the same stuff that I have used on land and water. The little Dometic, for instance, is wonderfully efficient.

That's an awesome video and an inspiration even to me who is completely off grid

[Adelie]

Originally Posted by sandy stone

... I just don't see how 1 HP (or 1-1/3 HP), with whatever propeller efficiency, is going to push a 34 foot boat at 3 knots, and I was wondering if you truly believe it's possible. .....

In the above SailingUma video at 10m50s they mention that at 3.5kt the electric motor draws 1.2kw. That's for a Pearson 36 which is 3.5-4.0k heavier than the boat I'm looking at, albeit on a longer waterline.

[barryglewis]

Originally Posted by boat_alexandra

Very good points. I suggest the OP look into dedicated hydro-gen or tow gen rather than regen for about twice the power for the same drag. This will have a repeller which is the inverse of a propellor. You can't just flip it around unless you were a 4th dimensional being.

I 3d printed a repeller that is 16 inches diameter and glassed over it, it produces half an amp in tidal current at anchor in charleston which has only a 2 knot current. Normally impossible to generate any power from this speed of current with a propeller.
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@ Boat_Alexandra, how do you design a "repeller"? Can you point me any links that discuss their design? What were the steps and equipment / Apps involved in the 3D printing of yout on? Is the pitch coaser or finer compared to a propeller?

Early 2019 in Opua, I met A "Waka" 50ft , one of half a dozen 50 and 70ft being used by Mauri / Polynesian groups. The simplicity and cleanliness of the "engine " room was very impressive! Apparently the whole fleet are in the process of converting from solar and electric propulsion to diesel running on a coconut based fuel

[Adelie]

Originally Posted by sandy stone

Even if not actually unsafe or illegal, it is certainly inconsiderate to use the entire width of a channel or bridge opening while tacking - especially at a bridge that has boats waiting on both sides to pass through. There is a drawbridge where I sail consisting of a railroad and highway next to each other, so an extended passage, that I would definitely consider dangerous to sail through. Also, it's quite a bit different short-tacking a 50' boat as opposed to a 27' boat.

To Adelie - Do you really believe in your heart that a trolling motor will push a Cal 34 at 3 knots?

Second response to this post:

The Uma folks just posted a video about Diesel Vs Electric Drive.

https://www.youtube.com/watch?v=EWFjxFkTWmQ

At 29m40s they had data for speed vs power.
Their old forklift motor used 1.6kW at 3.0kt
Their new electric sail drive used 1.2kt at 3.0kt.

Their boat is a Pearson 36 which is 13,500lb in the lightship condition.

The Cal 34 I want is about 4,000lb lighter so yes, I have plenty of confidence that an electric motor using 1.0kW could push a Cal-34 at 3.0kt, perhaps slightly faster.

[s/v Jedi]

Wow I missed that post stating it was probably illegal and unsafe but surely inconsiderate to sail through bridge openings instead of motoring and thus all sailboats must have motors.

I can rant all day but as short as possible: it is inconsiderate when you have a motor to be at all in the way of those without motor and sailing through. It is inconsiderate to not offer a tow through the open bridge when the sailboat is tacking upwind and you have a motor. It is inconsiderate to demand what others must have beyond what laws and regulations list.

And what that exactly has to do with boats with electric motors isn’t clear to me. When the open bridge is upwind, they simply use the motor to help push them through

[Brewgyver]

Originally Posted by Adelie

If there is no wind and you need electric propulsion, then the sails will all or mostly be down and most of the deck will not be shaded.

That was a adequate guess on electrical requirements.
Based on 36,000 lb displacement, 41.34' lwl and 5kt speed, a 19hp ICE engine would be required which is just about 14kw. In reality it would be more like 10-12kw but not bad for a guess.

I used Boat Speed Calculator to figure this out.

I guess Amel should have talked to you first. For some reason, the engine they put in was more than four times that output.

[Adelie]

Boat manufacturers size engines so that the vessel can proceed at hullspeed against significant wind and seas.

19hp ICE is to go 5kt (significantly less than hullspeed) in flat water.

I assumed readers could figure this out themselves. My bad.

[moseriw]

Oh man,
if somebody wants to throw out a 20.000 USD engine and replace it with a 40.000 USD electric propulsion for say max 1000 NM per year then please let em go.

Not worth to discuss it.

[Adelie]

Originally Posted by moseriw

Oh man,
if somebody wants to throw out a 20.000 USD engine and replace it with a 40.000 USD electric propulsion for say max 1000 NM per year then please let em go.

Not worth to discuss it.

If it's not worth discussing why are you?

A 60kW electrical drive for an Amel would be $18K + batteries.
For a 100Ahr (@96v) carbon foam battery pack that would be about $4500.
For a 360Ahr (@96v) Trojan Flooded battery pack that would be about $4800.

https://electricyacht.com/product/qu...lectric-motor/
https://docs.google.com/document/d/1...ltHp4GKrY/edit

It's a long way form $23k to $40k.

[moseriw]

you missed the generator for 10-15000 USD

[Brewgyver]

Originally Posted by Adelie

Boat manufacturers size engines so that the vessel can proceed at hullspeed against significant wind and seas.

19hp ICE is to go 5kt (significantly less than hullspeed) in flat water.

I assumed readers could figure this out themselves. My bad.

You assume a lot. You assume that sails being down equals "most of the deck will not be shaded" but assume that the shadowing from a tall ketch rig will have no impact on solar cell output. For that matter, you assume that lack of wind equals a bright sunny day and flat seas, not to mention no current.

That's a LOT of assumption, to put it VERY kindly.

[Adelie]

Originally Posted by Brewgyver

...You assume that sails being down equals "most of the deck will not be shaded" but assume that the shadowing from a tall ketch rig will have no impact on solar cell output.

Ketch, sloop, schooner, cutter..., with all sails down most of the deck will not be shaded. Next you are going to ask about the shading from a dodger and/or bimini.

I never said, nor did I imply that the masts and rigging would have no effect on panel output. Thanks for trying to put words in my mouth.

Originally Posted by Brewgyver

For that matter, you assume that lack of wind equals a bright sunny day and flat seas, not to mention no current....

I never assumed that nor did I ever state that. Again putting word in my mouth.

[Scaramanga F25]

For those that wish to transit the Panama Canal,
the minimum speed allowed is 5 knots.
Uma cannot attain that speed and only 3 knots for 40 miles. Not enough.

The batteries they have almost cost the price on an engine.

[yvest]

Originally Posted by Scaramanga F25

For those that wish to transit the Panama Canal,
the minimum speed allowed is 5 knots.
Uma cannot attain that speed and only 3 knots for 40 miles. Not enough.

The batteries they have almost cost the price on an engine.

They can reach that speed, but yes not long enough for the Panama canal most probably, then onboarding one or two honda generator could most probably do the trick.

But to me the major plus is that they end up with a big battery bank, and more importantly a powerfull hydrogenerator.

[lordgeoff]

Originally Posted by norbu09

Hi, I am new here, please let me know if I post in the wrong spot or make any other rooky mistakes

We live on an Amel Super Maramu in La Rochelle, France and work through our refit at the moment. We planned to go cruising soon but the diesel died so we are now looking at an electric conversion. We did toss many ideas around and landed on a system that I hope is easy to work on, easy to find parts for and good enough to get some first experience. Then, over the coming year, we plan to build out the system so it is fit to sail us home from France to New Zealand.

The system is built around a 48V Lithium battery bank that will service the boat needs and the engine. I have some initial drawings around the idea and would love to get feedback from those who have built systems like this.



The drive system will most likely be a oceanvolt AXC which runs on 48V.

The plan for the battery bank looks like this at the moment:



cheers
Lenz

Do yourself a huge favour. Get a new fuel efficient diesel engine. Install more than less diesel storage. Be grateful for whatever solar charging you get.
Enjoy hassle free sailing safely.