Diesel Electric Propulsion

[Scout 30]

I'll bet you have to go through a dealer to actually get pricing. Here's one in Florida.


Elco Electric Propulsion systems by Davidson's Marine Sercice | Davidson's Marine Service, Inc.

[valhalla360]

Originally Posted by Julie Mor

I was reading a section in a book by Nigel Calder regarding diesel electric propulsion. What I found interesting is he said (if I understood this right) if you design and size your battery/inverter system properly so that it can handle start-up loads, the generator needed to have a fully functional hybrid setup - that is one that can perform pretty much the same as a diesel auxiliary - can be as little as 25% the size needed if the generator is sized to handle start-up loads on its own.

Of course, the implications one can take from that are head turning. I imagined a forward-looking boat building company taking that and figuring out a way to replace the standard diesel auxiliary/battery bank normally installed and replace it with a D-E hybrid system, one that creates 120v power at sea, for a small increase in price. The general appeal would be huge.

We're already catering to the push-button, make-it-like-home consumer. But what isn't there is the electrical conveniences of home. Imagine offering that in a 30 footer. Bene and other companies have been focused on making the sailboat more like home. This is just the next logical step. Once the mass produced boats get on the wagon, it's just a matter of time before prices come down and make a D-E repower a no-brainer.

Sort of but not really.

Let's say you have a 40hp diesel and you want to replace it with a hybrid system.

If you use a 40hp diesel generator and slam the electric motors from full stop to full throttle, the startup load may stall the generator if the electronics aren't designed to ramp up the load on the motor. (similar to an air/con compressor that draws 2-3times the amperage on start up).

So with a crude design, it would be trying to draw the equivilent amperage of 80-120hp on startup from a 40hp diesel and thus you could claim to need a much smaller generator by using an inverter.

One solution is to run it thru a battery bank with an inverter that can handle the start up loads. For the second or two while the electric motor starts up, the batteries can supply the extra juice and then the draw drops back down to the 40hp range and the engine provides all the power.

The alternative is to use a controller that ramps up the electric motor so it never goes from stationary to full throttle. If you are running DC motors, you could wire up a battery bank to the same voltage to provide the boost without an inverter.

Where the 25% idea falls down is once the prop is turning and the boat is moving, startup load goes away. Once moving that 40hp diesel, after some losses due to friction in the transmission, you are probably getting somewhere around 35hp at the prop. You can gain some efficency with the electric motors because they don't neccessarily need a transmission (just reverse the current to reverse the motor) but the savings are lost in the process of converting the generators mechanical energy into electrical energy and then back to mechanical energy. Even worse with an inverter system is you convert mechanical energy to electrical, then convert it to stored battery energy, then the inverter converts it to a different form of electrical, then it's converted back to mechancial with losses at each step.

Horsepower has a definition that does not care what the source is, so once moving, you need a certain amount of HP to maintain a certain speed.

[misfits]

Originally Posted by Scout 30

I'll bet you have to go through a dealer to actually get pricing. Here's one in Florida.


Elco Electric Propulsion systems by Davidson's Marine Sercice | Davidson's Marine Service, Inc.

Thanks for the link. Elco just got back to me stating they do not offer any discounts off msrp. I suspect their dealer network sells off the msrp & they probably get a 10%-20% discount off the msrp for selling the product.

I think it's a great product but for me I'd rather go with if you do a diy kit from one of the vendors. It leaves you with a bunch of money for other upgrades such as solar, wind generator, etc.

[Scout 30]

Might be worth contacting a dealer just to find out if you can get a bread off of the list price. I agree that they seem quite expensive but they also look like the best marine electric motor out there right now.

[Stumble]

Originally Posted by Sailingcouple13

The Gunboat 55 is now standard with electric drives. The Diesel is available as a $75,000 option.

Sent from my SM-G900P using Cruisers Sailing Forum mobile app

No the Gunboat 60 Ecco was supposed to come with electric propulsion not the 55. But to my knowledge none of them were ever delivered. They also came with two 25kw diesel generators to power the electric motors. And massive 144v 55kw lifepo battery banks. This is high enough voltage that a short will kill you immediatly.

The Ecco was specced to run at full power for 30 minutes with both generators running. Which works out to installed drive motors around 50kw. Which is right in line with the 50hp diesels the normal GB60 uses.

So far as I know the boat, much like the lagoon attempt, never really made it past the design phase before everything started falling apart. But if you know of any launches please let me know I would be fascinated to read about them.

And yes I know about Moonwave, but the reports are mixed at best. And I don't know of serial production intent yet.

[wsulli]

When I was considering electric for my Pearson 30 I looked into the products at
ThunderStruck Motors - Electric Vehicles, Accessories and Components they seem more reasonable than many others. They are not plug and play like some of the others, but you can save if you can do it yourself.
I got a great deal on a Yanmar seemed easier and much cheaper $1500 total versus about $6k for electric.

[Lepke]

As several others have said... It's much more expensive than a diesel and transmission. I ran US Navy tugs with this system. IT was great! I could turn as slow as 1rpm and go to full throttle. We had 2 diesels running 2 generators that fed power to 2 electric motors on the reduction gear. I've seen large navy tugs with 4 diesels and generators and a single shaft. For cruising one or more diesels is on line and for towing all diesels are on line. Should one part fail, I could still tow at reduced power.
As a64pilot has said, subs have been using this system for a long time. New diesel electric subs are still being built. Also Locomotives. When you see a string of locos pulling a train, you see a heavy cable going between locos. That connects the other loco controls to the lead engine controls. Only one crew controls all the locomotives. Another reason steam engines lost out.

[Hyprdrv]

Wow this just gets better and better.
IF your interested in the Lagoon story do a search of my posts over the last 6 years. I own 1 of the 3 still going strong Lagoon 410s Lagoon didn't screw with.
People are comparing apples and tomatoes when it comes to HP requirements between Electric and Diesels. They ARE NOT THE SAME.
I operate my 18k lb cat with 2 12HP motors to 8 knots.
Costs have come down quite a bit for the systems.
With my 16kw genset I can run as long as I have fuel. Everything runs through the batteries at 144V.
I've burned 40 gals of fuel on the Bay over the last 5 years. That's for a weekend cruiser with a few week long jaunts.
My boat came up from the Carib. with batteries fully charged, even to the point that the air conditioning was run do to regen from the props.
The fun thing is to go back and read what people were saying In 2010 verses now.
"It will never work"....


Steve in Solomons MD
Lagoon 410 S2E

[BigBeakie]

Originally Posted by Hyprdrv

Wow this just gets better and better.
IF your interested in the Lagoon story do a search of my posts over the last 6 years. I own 1 of the 3 still going strong Lagoon 410s Lagoon didn't screw with.
People are comparing apples and tomatoes when it comes to HP requirements between Electric and Diesels. They ARE NOT THE SAME.
I operate my 18k lb cat with 2 12HP motors to 8 knots.
Costs have come down quite a bit for the systems.
With my 16kw genset I can run as long as I have fuel. Everything runs through the batteries at 144V.
I've burned 40 gals of fuel on the Bay over the last 5 years. That's for a weekend cruiser with a few week long jaunts.
My boat came up from the Carib. with batteries fully charged, even to the point that the air conditioning was run do to regen from the props.
The fun thing is to go back and read what people were saying In 2010 verses now.
"It will never work"....


Steve in Solomons MD
Lagoon 410 S2E

Hi Steve,

Thanks for putting your positive experience forward with your "original EP" Lagoon. Gets a bit lonely trying to talk EP on the forum, doesn't it?

Where were you when I needed you over in the Multihulls forum on the thread "Using electric motors instead of Diesels on your cat" ?

[skipmac]

Originally Posted by Hyprdrv

Wow this just gets better and better.
IF your interested in the Lagoon story do a search of my posts over the last 6 years. I own 1 of the 3 still going strong Lagoon 410s Lagoon didn't screw with.
People are comparing apples and tomatoes when it comes to HP requirements between Electric and Diesels. They ARE NOT THE SAME.
I operate my 18k lb cat with 2 12HP motors to 8 knots.
Costs have come down quite a bit for the systems.
With my 16kw genset I can run as long as I have fuel. Everything runs through the batteries at 144V.
I've burned 40 gals of fuel on the Bay over the last 5 years. That's for a weekend cruiser with a few week long jaunts.
My boat came up from the Carib. with batteries fully charged, even to the point that the air conditioning was run do to regen from the props.
The fun thing is to go back and read what people were saying In 2010 verses now.
"It will never work"....


Steve in Solomons MD
Lagoon 410 S2E

Hi Steve,

Thanks for the report. I am quite interested in electric for my 42' boat but have not been able to satisfy a number of questions. Ignoring for now the much higher cost I still have some technical concerns.

You are powered by 2 X 12 HP electric motors that will give you 8 kts. Is that in a calm or with weather? For example motoring dead into the wind at 15-20 kts and 3-4' waves. Can you make 8 kts in those conditions?

I do agree that a lower HP electric can give similar performance to a higher HP diesel due to the parasitic loads on a diesel and the different torque curve of electric but my thoughts are the difference would be 20-30% at best. I just am not sure that I could power my 25,000 lb boat with 24 HP or even 34 HP.

You said you ran your air con with the power from your regen under sail. So the regen system can consistently give you greater than 100 amps at 12V DC or better? Does the system add much drag in use?


Thanks
Skip

[Hyprdrv]

Hi Skip,
First off the Cat has a large face to weather above the decks so any direct windage dead on is going to have an effect on speed. In the conditions you mentioned I would probably do around 4-5 knots. With those conditions I would tend to tack instead and continue to sail as much as possible. I run into those conditions on the bay quite often and will hug the shore to lesson the sea state. The 410 came standard with 28HP diesels. Go to https://groups.yahoo.com/neo/groups/electricboats/info


and see what a few sailors with large Monos have done. These guys are doing it! Depending on where you are there are companies on both the east and west coasts that have done conversions or supplied equipment that could size the motors for you.


Don't forget that the Electrics have a lot more torque. Even at 9 tons I can get up to speed in a boat length and even come to a complete stop in that length. The real issue is selecting the prop (bigger and higher pitch) to maximize the motors. I run 18" props. And no folding ones. No regen if they fold up. I could care less about loosing a knot under sail when I'm above hull speed already
The story on the A/C was not mine but the owner of the first 410E "Waypoint" coming across the Atlantic. The Regen had fully charged the batteries so they had to "bleed of power. The real solution was to put the motors "slightly" in reverse so the regen wasn't working but they forgot to tell the owner that before they left.
First Electric Lagoon Crosses Atlantic to Annapolis...Then Heads to Tortola
Electric drive for Lagoon catamarans


The Generator and Regen go directly to the 144V bank then power is sent to the house bank through a charger (144V to 12V). I run a 6KW Inverter to go from 144V DC to 120V AC for the A/C system or any other 120V appliance (a hair drier comes to mind) at anchor. To reduce loads on the Propulsion bank I plan on 2 solar panels off the Davits. They don't make a controller (yet) to go to 144V plus I don't plan on covering the decks in SP's.


Steve in Solomons MD
Lagoon 410 S2E

[Seaguy]

I am nearing the end of a custom design/build of a 50' performance catamaran. I looked into using electric drive and gave up after exploring multiple options of generators/battery banks/solar panels/electric motors. The problem is basic physics -- you cannot convert diesel to electricity and then use that to drive an electric motor without significant loss. And the power derived from solar panels is just not adequate for any significant run time on electric motors. Say you have an 8kW motor. That means you need 8 hours of sun on your 1000 watt solar system (about 8 4'x2' panels) to run one engine for one hour (and that is assuming you have 8kWh worth of battery storage (well over $5,000). Of course you don't typically run at full power, so this is not a totally fair comparison, but you also don't get close to 100% output from your solar panels so the comparison is still valid.

You need a large generator and large (expensive) battery bank and/or large solar array or you end up with significant tradeoffs and that still requires you run your generator most of the time while motoring. I considered a single generator, batteries, solar, and two electric drives but it was significantly more expensive, heavier and had a limited range when compared to a conventional diesel system.

The only system that could come close in terms of cost, efficiency and weight (suitable for a catamaran) was a single diesel engine with very high output alternator on one side and a single electric drive on the other side and a reasonable sized battery bank. This system (with batteries) could be installed at a similar or even slightly less weight & cost, but you end up with tradeoffs that might be OK for some. You can't run both engines for long periods of time, but it would let you motor for long periods on a single engine and then use both when needed for maneuvering. Yes, it is a sailboat but sometimes the wind doesn't cooperate.

There are lots of examples of these type of systems that do work, you just have to be willing to make tradeoffs in terms of performance, cost and/or weight. I ended up going with a two diesel Yanmar saildrive system. It is lighter, reliable, redundant, cheaper and more efficient than a similar performing hybrid system.

[Hyprdrv]

Seaguy you didn't mention what Voltages you were looking at for your system but I'll assume it's probably 72V based on the dollar amount you mentioned for the batteries.
Some simple math.
My 16KW genset burns a hair over 1 gal an hour. with 40 gallons (in the tanks) on board that's say 38 hours. The genset puts out 170V DC for a max charge rate of around 164V to the 12 pack of AGM's. Note: AGM's and LA's are only good for 50% of their energy until you have to start thinking about recharging. Max Amps supplied is about 110A


At 144V my motors (2) use around 60A to maintain 7knots.
At 72V you need to double that to 120A (still 8.6KW)


So you have 2 diesel motors to spin your props and a Genset on board. Those 2 motors are going to double the fuel used plus the wife wants that hair drier running so you need the Genset on every so often. How is that more efficient?


So let's look at generators for a second. The new ones are lighter and much more efficient than mine is but it still weighs less than the 2 motors and sail drives your boat will have. I can carry the electric motors out on my own (about 120# each) by the way. So let's just say it's a 300# savings at this point. You have to maintain 3 motors were I have 2 of the 3 that require checking the torque on the connecting wires once a year and replacing 2 shaft bearings (at a cost of $20) every 300,000 hours of run time. No my fingers didn't stutter.


So we get to the BIG ticket item, the Batteries.
My AGM's are Northstar's, 210AH about $800 each x 12 = $9600. Probably the best LA batteries out there. Recommended a max 50% discharge (Northstar says 60%). They weigh around 140# each for a grand total of over 1700#! That is the best you could do 10 years ago. I've gotten 8 years of service (Not sure but I think NS says about 500 full cycles) out of them and the one thing everyone has to do with Electric Propulsion is maintain their batteries religiously. For that matter everyone does but that's another string..
So today we have the option of LiFePo4 batteries, 180AH at $250 x 48 = $12000.
That might throw a few people into a tizzy but look at the advantages:
Life expectancy is 5000 cycles = they will out live me.
Weight 12.5# x 48 = 600#. a savings of close to 1/2 a ton.
1/2 the space needed.
A discharge down to 20% (10% if you push it) vs 50% = 30% more energy available. I would hope a run time on batteries only of around 7 hours.
Much faster charge time = less genset run time.
With these batteries I'll probably never exceed 1/2C which is pretty gentle on them. When you crunch the numbers the LiFePo4's win hands down.


All in all the system is pretty simple once you break down the components. There is some thought behind the way you approach the wiring and then you are looking at an AH meter rather than a gas gauge. You don't need to shift the motors from forward to reverse, just throttle down and keep moving down to go backwards. I did put a noisy blower fan on one side to remind me the motors were on and even then have had the wife remind me I hadn't shut the keys off.


Quick story, I was under power coming into the creek when a 40+ mono comes across my stern under full sail. The Captain says "you running electric?" I say "how did you know?" He responds "I'm not yelling am I?." So there is the cool factor.


I've burned more fuel getting rid of it do to concern of the fuel going bad then I've probably used to generate electricity by the way.
There are a lot of things I've probably forgotten to mention. In your case under your conditions it may not be the right thing. I've heard a lot of concern about headway, distance issues, spare parts, something for nothing, costs, ect. ect. It works for me and I get to meet a lot of people who have "heard" about Electra Glide. There are a number of people on the Chesapeake running Electric, some good size sailboats and even a classic Skipjack under electric power. This isn't going away, in another few years there will be even more people on the Electric side of the fence.


One last note because you mentioned your boat was a "performance" cat.
Didn't Gunboat select Electric Drives for their 60' cat? Pretty much the same system I have onboard EG.


Steve in Solomons MD
Lagoon 410 S2E

[ranger58sb]

Originally Posted by Hyprdrv

So today we have the option of LiFePo4 batteries, 180AH at $250 x 48 = $12000.

Steve in Solomons MD
Lagoon 410 S2E

Steve, can you hum a few bars on where to source LiFePo4 batteries -- to make up a 12V system of approx. 450-600 Ah -- for that kind of price?

-Chris

[Hyprdrv]

EVTV Motor Verks Store:
Jack Rickard is a known guru for electric systems for cars and is just now getting into small classic speed boats. Worth looking at some of his TV productions. By the way that price includes battery straps but not the shipping from his door to yours.


Steve in Solomons MD
Lagoon 410 S2E