Diesel Electric Propulsion

[nimblemotors]

To apply the same reasoning, why have solar panels if you still need an alternator/generator,
and why have sails if you still need an engine.

Originally Posted by goboatingnow

I see no advantage, since you cannot yet remove the need for a IC engine., you might as well use it for propulsion.

[44'cruisingcat]

Originally Posted by goboatingnow

I see no advantage, since you cannot yet remove the need for a IC engine., you might as well use it for propulsion.

This. Except that you also introduce many more areas for failures to occur.

[44'cruisingcat]

Originally Posted by nimblemotors

To apply the same reasoning, why have solar panels if you still need an alternator/generator,
and why have sails if you still need an engine.

If you have enough solar you pretty much don't need a generator. I haven't quite worked up the courage, but I really should take the little Honda genny off the boat. We haven't needed it since I added an extra 200 Watts of solar. Not once. I give it a run every so often to stop it rusting up.

I'd get rid of the engines before the sails, and the fact is, mostly it's only laziness and impatience, "convenience" that makes me use the engines.

[downunder]

Originally Posted by Julie Mor

Seems Torqeedo already has a video that exceeded my imagination:

Julie,

I expect the Torquedo system may shock you with price although if it works as in the film it would be great.

That's why they have a Gunboat as a demo so you won't be worried about price if buying a Gunboat. Torquedo bought out the german company that developed the system.

[ranger58sb]

Originally Posted by downunder

Julie,

I expect the Torquedo system may shock you with price although if it works as in the film it would be great.

That's why they have a Gunboat as a demo so you won't be worried about price if buying a Gunboat. Torquedo bought out the german company that developed the system.

I tend to agree; Torquedo pricing for their "simple electric outboards" is.... ummm... adventurous, at the very least. Perhaps economically justifiable at this stage, from costs of development and so forth, but still can be a big jolt (pun) to some of us mere mortals.

Their approach here seems very well thought out, though. It seems to make good, balanced use of several complementary systems -- sail, solar, batteries, prop regeneration, inversion, shore power, and yes, a diesel generator when necessary -- instead of throwing all their eggs into one basket and calling it good.

The video didn't mention much about batteries -- size or chemistry -- but I'd guess that'd be a hefty cost if they assume they can run an AC air conditioner for extended periods at anchor... before needing to fire up the genset.

The sail makes it easy, I think. If I could afford a sailing cat with a decent flying bridge I might be tempted already. And the azipod maneuverability would just be additional gravy.

And if costs gradually decrease over time and as battery chemistry evolves, so much the better.

-Chris

[goboatingnow]

Originally Posted by nimblemotors

To apply the same reasoning, why have solar panels if you still need an alternator/generator,

and why have sails if you still need an engine.

You have sails because
( a) they are significantly more economical

Many people do not have solar ( in fact the majority ) and do rely on alternator recharging


Diesel electric on small boats , offers no real advantages , is extremely expensive , potentially more parts to fail, and often is underpowered.

I see no compelling advantages and so it seems neither does the industry, other then a few early adopters , or techno geeks.

Dave


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[goboatingnow]

Originally Posted by 44'cruisingcat

If you have enough solar you pretty much don't need a generator. I haven't quite worked up the courage, but I really should take the little Honda genny off the boat. We haven't needed it since I added an extra 200 Watts of solar. Not once. I give it a run every so often to stop it rusting up.

I'd get rid of the engines before the sails, and the fact is, mostly it's only laziness and impatience, "convenience" that makes me use the engines.

I have no yet seen an equivalent capability to a diesel engined boat, which can be driven by solar , I have seen people arguing that replacing a 50 hp diesel capable of running for more then 2-3 days straight, with a 10hp electric capable of a few hours of running as " equivalent ". Please. !!!


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[Lodesman]

Originally Posted by Julie Mor

Does anyone here have this system in place? Do you know anyone who does? What do you think? Is this the future?

As someone has mentioned, a forumite Mbianka has electrified his Nonsuch - the blogs are quite informative: THE BIANKA LOG BLOG
I think he's going on 7 years now, so would weigh his opinions over those of the armchair experts.

[Lodesman]

I should have added the caveat that Bianka is not diesel-electric per se, but a lot of his experience is directly translatable. I've served in D-E naval vessels. While I don't think that experience can be related to the topic in any meaningful way, I note that there seems to be the mindset that in order to power an electric vessel, you need to fit an IC generator capable of producing more than enough power to cover the max load of the engine(s) and other systems. This of course leads to an oversized genny running at a fraction of its capacity most of the time. In the naval vessels they had 4 generators - most of the time only 1 or 2 would be required to be run; if more power was needed, another genny was flashed. I don't see why it wouldn't be possible/feasible for recreational vessels to have two smaller generators and a combiner, to cover the gamut of power needs from normal cruising loads, to the ability to run flat out for extended periods.

[Julie Mor]

Originally Posted by skipmac

After much reading and research on electric power it comes down to this.

1. Commercially available systems are much more expensive than a standard diesel including the transmission. Some as much as double or triple the cost.

2. Have not yet seen a commercially available system that has power equivalent to my 58 HP diesel. Most top out around 12-25 kW (16-32 hp).

3. Even if you fill a boat with batteries and solar to charge you will only get a few hours under power. To get more range you will have to add a generator so now you're back to having an engine with the fuel and smell and maintenance that you were trying to get rid of. Plus you have added even more cost.

My conclusion, electric is fine for smaller boats for short runs like dock to channel, mooring to the bay, etc. Anything more, it's not yet ready for prime time.

1. Initially, all technology is expensive compared to the existing, often antiquated, systems. But in the end, new technology usually replaces old technology as costs become comparable.

2. Torqeedo has two inboard motors, rated at 40HP and 80HP. I couldn't find where Oceanvolt rated their motors by HP, only kW, but their website stated they have inboard motors for up to 60' cats and monos.

3a. From what I've read, you can get almost countless hours running on electric power, just not continuous for very long unless you add a generator.

3b. If you need to repower, the cost of the generator can be deducted from the cost of a new auxiliary. You could still be ahead at that point and have 120v power aboard you never had before. Yes, there will initially be a higher overall cost, when all the parts and pieces of the hybrid system are in place. But there are long term savings that should be figured into the equation. From what I've read, the hybrid system is more efficient than the auxiliary alone. The fuel and maintenance cost savings on the electric only system is obvious.

Right now, the system created by Annapolis Hybrid Marine is just as you stated, something to get you in and out of the harbor or poke along on short runs. And it needs no IC engine at all for that. Electric motors require much less maintenance, almost nothing compared to diesel and they burn no fuel. The weight of the engine and all its components are gone as is the weight of the diesel fuel. There's savings there too.

The hybrid system will certainly be more expensive, but for the boat owner who wants a generator or has to repower and replace the generator at the same time, the additional costs may be negligible, especially when figuring in long term costs.

[nimblemotors]

Annapolis Hybrid Marine's website shows they are a reseller/distributer of existing products. So nothing new here.

It really isn't complicated to have an electric drive. And a generator.

An electric outboard however requires more design work.

The 'total integrated system' approach sends up warning flags of proprietary parts and super expensive single-source repairs. The richie-rich billion dollar yacht guys are not fazed by this, they hire people for that, us mortals might only have an app for that, or a repair manual.

[a64pilot]

If your an Engineer type and or a talented mechanic, from a curious look, a Hybrid automobile is illlogical. They are way overweight, complex and expensive. The weight of two motor/ gen's electrical components and the large battery simply requires a vehicle of a size and weight carrying capacity that in no way can be as energy efficient as a light weight vehicle with only an internal combustion engine, especially in highway use where th eelctric components are not being used, they are just excess weight that has to be hauled around. A Hybrid automobile is a gimick that just can't work.

But they in fact do work, largely because at least some do not use an Otto cycle engine, like all non-hybrids do, the electric components allowed an engine to be used that would not work in a conventional automobile.
It is possible to tune an engine to only work well in a very narrow RPM range and at a set load, might be what it takes to make a Hybrid boat more logical?

So, Hybrid cruising boats may well be the future of cruising, just not I don't think in my cruising time.

If you look at and understand why and how hybrids work, why are City busses and vehicles like that, not Hybrid?

Hybrid technology for some reason seems to not be logiaclly applied, seems to be a marketing thing more than anything else?

[RaymondR]

I have seen a couple of electric auxiliary sail boats where the owners were quiet happy to rely upon the very limited power and endurance capabilities of their electric auxiliary power systems to get in and out of port or anchorages and relied entirely upon their sails only for voyaging. Not everyones cup of tea but if you like a challenge occasionally and have good nerves, go for it.

I spent most of my life as an oil driller. The smaller rigs I worked on had chain transmissions and air clutches and were hard to beat for ruggedness, simplicity and reliability. The major problem was that skilled as one became one could not completely avoid occasionally stalling the engines and the racket from loose chains when one engaged a clutch could be a little startling.

Just about all bigger mechanically driven rigs had torque converters in the drive lines so there was not the stalling or banging problems but torque converters waste power. The up side is that like the direct drive systems these were very reliable, durable, uncomplicated systems.

The penetration of diesel electric power generation and transmission systems came with the advent of offshore drilling in the 1950s. Footprint extent and system distribution considerations bought diesel electric to the fore as the preferred power system (although one offshore contractor persisted with steam powered systems well into the seventies) The equipment used was borrowed from the railroad industry where diesel electric traction systems were developed to replace steam.

In addition to it's footprint and location flexibility advantages diesel electric allowed a lot of flexibility as to where power could be conveniently routed however one still had to have a large DC traction installation along with a fairly large AC service power installation.

The dual AC and DC power generation systems requirements were replace by silicon controlled rectifier systems where only a limited number of large AC alternators were required to power both the AC service systems and the DC traction systems. These are very efficient and flexible systems as they allow the running of only the number diesel engine power generators required to service the highly variable power requirements of both the AC and DC loads.

As well as the drilling power requirements the diesel electric systems on the mobile offshore drilling units can provide propulsion and positioning power. Some moored floating rigs use DC motors for propulsion and the deep water rigs use thrusters to hold the rig on position dynamically, all of which can be powered by the same systems used for drilling power.

Bit off topic but I though some might find it interesting.

Since this is a "what if" discussion I can perceive a set of circumstances where an IC, or EC, electric power generator and an electrically driven propeller system could be a great propulsion system for a boat.

The main circumstance is the availability of low cost, multi fuel, turbine or Stirling system powered generators. These tend to very light, compact power generation packages of much interest to the aerospace industry. One of these well sound proofed and stuck away up up the bow or stern quietly powering a retractable electric motor/prop, steerable thruster would be an improvement on having to live with a bulky, noisy, smelly diesel with a leaking stern gland.

[David M]

As for new ships, some plants are diesel-electric and some are direct drive (Diesel-transmission-shaft-propeller) Much has to do with the house load and cost savings with not having to hire an extra tug or two. The largest Diesel in the world is a direct drive plant. The cost advantage of each depends on the vessels function. New tankers, bulk carriers and container ships tend to be direct drive. Passenger ships, offshore supply vessels and large fish processing plants tend to be Diesel-electrics.

[skipmac]

Hi Julie,

Thanks for the update on Torqueedo. Have not checked their product line for a year or so and was not aware they now offer larger inboards. Will go check that out.

FYI simple conversion 1 HP = 0.746 kW. So my 58 HP diesel in theory would take roughly 44 kW electric. However the comparison is not quite that simple. Several factors to consider.

ICE have a lot of friction and parasitic loads that reduce the actual HP delivered to the prop. Friction in the transmission, HP to drive water pumps, alternators, etc

Also power from electric vs ICE is different. Electric motors develop full power at initial rpm but diesels only develop full power at much higher rpm. Depending on the engine and design in the range of 1500-2500 rpm.

Bottom line, you should be able to get the same performance from a lower HP electric motor than the equivalent HP ICE.

More comments below.

Originally Posted by Julie Mor

1. Initially, all technology is expensive compared to the existing, often antiquated, systems. But in the end, new technology usually replaces old technology as costs become comparable.

No disagreement at all on this point. I'm just not usually in the group to pay the big bucks to be the first on the block with the new technology. Not only is it generally a lot more expensive but is often much less reliable until there's more real world use to get the bugs out.

2. Torqeedo has two inboard motors, rated at 40HP and 80HP. I couldn't find where Oceanvolt rated their motors by HP, only kW, but their website stated they have inboard motors for up to 60' cats and monos.

Thanks.

3a. From what I've read, you can get almost countless hours running on electric power, just not continuous for very long unless you add a generator.

Exactly. Which loses one of the advantages sought by many of the boaters interested in electric. Go electric to get rid of the diesel and all the associated issues but then buy a diesel generator to run the electric and you're back where you started but with a lot less money and additional systems on the boat to operate and maintain.

3b. If you need to repower, the cost of the generator can be deducted from the cost of a new auxiliary. You could still be ahead at that point and have 120v power aboard you never had before. Yes, there will initially be a higher overall cost, when all the parts and pieces of the hybrid system are in place. But there are long term savings that should be figured into the equation. From what I've read, the hybrid system is more efficient than the auxiliary alone. The fuel and maintenance cost savings on the electric only system is obvious.

As I pointed out, I've researched commercially available systems and the cost was 2-3 times the cost of a new engine and transmission. Would take a long time to amortize that cost in fuel savings. Plus if you motor long distances and have to run the generator there goes the fuel savings.



Right now, the system created by Annapolis Hybrid Marine is just as you stated, something to get you in and out of the harbor or poke along on short runs. And it needs no IC engine at all for that. Electric motors require much less maintenance, almost nothing compared to diesel and they burn no fuel. The weight of the engine and all its components are gone as is the weight of the diesel fuel. There's savings there too.

For in and out, I have always agreed that electric will work. But if you do the ICW or rivers and canals like those in Europe then you have to have the range.

The hybrid system will certainly be more expensive, but for the boat owner who wants a generator or has to repower and replace the generator at the same time, the additional costs may be negligible, especially when figuring in long term costs.

There is another benefit to electric that I haven't seen mentioned in this thread, one that is of interest to me and might be the one that justifies the switch if/when I repower. That is the flexibility in where you mount the motor. Since the electric is a fraction of the size of a engine/transmission you have great options in how and where you install it. In my case I have a V-drive that puts the prop shaft and stuffing box under the engine which is a bit of a pain. Going electric would allow me to off that setup and give much better access, even after I add the generator, which is also much easier to install that an engine since you don't have to deal with rigid mounts, shaft alignment and such.

I think you can see that I am not opposed to or prejudiced against electric. In fact quite the contrary. I just do not yet see it as practical and cost effective for my style of cruising.

One other thing that turns me off to the current marine electric systems. I just cannot understand why the motors are SO EXPENSIVE. I have purchased a continuous duty industrial motors for a home project and they are a fraction of the price of similar sized "marine" electric motors. We also drive a Prius (so another argument that I'm in favor of electric and hybrid systems) and I checked the price for a replacement electric motor for the car, under $1000 (not installed). So how come "marine" electric motors are thousands and thousands?