Diesel/Electric Propulsion System Design - Have your say!

I'm aware of that. It's a concern with transversal loads coming from belt driven gear, not same with torque forces as in my plan me thinks. Of course I will consult the engine manufacturer before, but I don't see a problem (blind)

 

Hello CatBuilder,

If you have not finalised the purchase of your propulsion system just yet, consider contacting Asmo Marine.

http://www.asmomarine.com/2005/asmo_uk/07.shtml

Good luck.

 

Thanks for sharing all of that. It is a great reference point.

I did look into Sonic legs, but now that the USD is in the toilet, the $7000 GBP price tag is really $11K. That's only for the drive legs... nothing to do with motors, generators, controllers, etc...

I can't afford $11K for these units, unfortunately. I need the money for other parts of the systems.

 

Finished?!?! Ha ha ha ha! That's a good one.

If I could only get started.

I will check Asmo Marine. Thank you for the tip.

 

Cat builder, why don't you call Mastervolt and ask them what the price point for combined propulsion and electrical distribution where they think hybrid becomes attractive. I think you will find that it is still ten times your budget. IMHO, the fact that you want a part time charter and part time live aboard works against hybrid. As any new tech, it tends to be a niche requiring a 100% duty to make it go. I think you are mistaken in thinking it offers an inherent advantage in versatility. Any system you can dream of in hybrid can be built in diesel. If its not commonly done, then there are reasons.

 

Phil, all systems designed to be sold by companies such as Mastervolt, Green eMotion, etc... are all way overpriced when you can just buy the components off the shelf.

They all use mostly standard components and pretend to have "invented" something. There is no mystery behind this stuff and these guys are trying to make huge profits by pretending an electric motor, a controller and a genset with some inverters is some kind of high tech setup they invented. It's not. This stuff is in every factory in every country in the world - chemical plants, offshore oil rigs, etc...

It's also been in use on boats since the 1800's. Hardly high tech.

It's the same pricing with a catamaran. I could go out and buy one for more than twice the cost of materials. If I make it myself, it's a good 50% less than manufacturers charge *and* I get a better boat. Pretty much everything works like that. No need to pay exorbitant markups on off the shelf electrical components.

I doubt MasterVolt is charging $200K-$300K for a system (10x my budget). eMotion hybrids was $70K for the system and I feel they are over double what a system costs if you buy the components yourself. Granted, they are the best money can buy with fantastic features, but I'm not looking for all that whiz-bang stuff. I am only looking to move a boat when not sailing and use some of the excess electricity to power heating and air conditioning. I don't need to spend $70K to do that, but eMotion hybrids has no simple, budget package. It's all complex and expensive. I suggested to them that they add a simple package to reach more customers.

Please do expand on the part where you say, "part time charter and full time liveaboard works against hybrid." I see it as a good fit, but you don't. I'm open to new ideas, so please let me know why you don't see a fit so I can consider your logic.

 

Catbuilder, while I agree that mastervolt stuff is dear. The fact is that "This stuff is in every factory in every country in the world - chemical plants, offshore oil rigs, etc... " is not the case. Electric propulsion on a boat firstly needs high performance motors.( because you cant sacrifice weight for power) If DC you're into rare earth magnets and electronic commutation. if AC you are into high frequency inverter controllers. At the power your talking about These controllers are expensive.

Even 35K is over double the cost of two small diesel engines.

In your sceanario, you are going to need a very big genny, equally this is a single point of failure, whereas a diesel cat would have redundancy.

I cant see the solution being available out of "off the shelf parts".

Dave

 

Thanks, Dave.

I understand your earlier post now. I also agree that $35K is more than the cost of a pair of diesels. However... and this is a big one...

$35K is less than the cost of 2 diesels, 2 saildrives, 2 fuel systems, 2 sets of through hulls, a generator, a large inverter, a marine heating system and marine cooling system for a 45' x 25' catamaran and a propane system. Most of which is eliminated with the diesel electric.

Those are the systems I aim to replace. Not just engines. Remember: I have an empty hull here. If you look at the problem in bits and parts, you end up spending more and having a hodge podge of things stuck together. The reason the electric drive system (and electric power takeoff from it) works so well (in theory) is that I am meeting all the boat's demands with one simple system. Less complexity.

Again, think back to my earlier heating example from this thread. How would you heat a 45' catamaran with a 25' beam? Espar? Propane heaters? Hydronic?

Well, if I have the diesel electric system, I use 4 ceramic heaters I buy in WalMart for $30 a piece. How much more than $120 does your Espar system cost?

The problem is you are not seeing the entire boat at one time. That's the key to efficient systems design at a low cost. I save a bundle on heating systems this way, for one. There are many many more things I can save a bundle on using this power source.

I don't care about a single point of failure, actually. I've had diesels for about 20 years now and I've never had one break down in a way I couldn't fix while underway. Most of this was in monohulls, but my last boat was a catamaran. I have a sailboat too - a good one. This is only auxiliary power. If the big generator breaks, I can fix it... or if I can't, I can sail in and use my batteries just to dock, then fix it at the dock (nobody works on my boats except me). If I'm dismasted and my generator dies, I still have an anchor to lie at while I fix the genset.

There are several layers of redundancy on a sailing vessel by definition.

I'm talking 3 phase AC motors and genset with 10-12KW variable frequency drive controllers. Those aren't very expensive at all, and yes... they are in use all over the planet in industrial applications.

 

As for heating, Espar is the way to go. Ive had very good experience with both Espar and Webasto. Electric heat is fine when on sufficient shore power but you cant use it when sailing or at anchor and do consider that 16 amp 220 shorepower is the norm in 90 percent of the ports I visit. fire up the electric heaters and poof ! you are going to be reaching for your flashlight then heading out to reset the blown shorepower box at three in the morning, dressed in PJs, fumbling for your reading glasses, as the cold rain pours down.

A nice detail for the yachts AC power system is to break it into two legs with a relay...Leg A only energizes wall outlets plus the battery charger...Leg B energizes the complete ships AC power system. It will save you many midnight trips to the shorepower box.

 

Michael. I do appreciate your input greatly on this thread, but I have to ask if you read and understood my last post. I ask because the post I am quoting from you makes zero sense when related to the topic at hand.

With a diesel/electric setup, the $30 heaters can all run off the same generator that makes the power to move the boat forward. There is no dock. I don't go to docks. With the electric system, I have the power to run all those electric heaters at anchor, as long as I have fuel. I have 95 amps of power available to use with the $30 heaters AT ANCHOR, if I'm at 220VAC.

That is why the electric based drive system is more economical than the standard setup when you are looking at an empty hull.

Geez. I am beginning to wonder if this thread was a bad idea. Some posters aren't even understand the concept of the system.

Epsar is *not* the way to go if you are putting in a huge electric source to run the drive motors. Putting in Espars would be a colossal waste of money and time. That is the entire crux of my system's design!

 

Heating?

WHAT,... is all this talk about heating? I do not understand!!

Steve in South Florida

 

Ha ha ha ha ha!

That's air conditioning to you, my friend!

Same logic applies though. Spend $10K+ on a marine air conditioning system for a 45' x 25' catamaran and have to maintain them, or have the large electric generator run a standard household unit carefully installed (to be hidden well) in the deckhouse and wheel portable ACs into the staterooms if required.

Far less expense and no through hulls.

 

Sure I read it Catbuilder...you spoke about the cost of a Diesel heater compared to electric. Diesel is the way to go. Electric requires much generator time or stored energy and is a convenience appliance that you will throw away each season. Its not part of the ship.

As for you never coming ashore...docking...Im scratching my head . Perhaps your geographic cruising grounds have no docks ?

I use about 350 liters of fresh water per day with guests onboard..how will you replace this ? Im a sailor...when working, sailing , its unacceptable to run generators. We sail all day. When sleeping its unacceptable to run generators. The only way I can possibly replenish stored energy and water is a weekly port call, 24 hrs charge , a water tank fill plus 1000 litres of water spread over the deck to wash away the salt, flying fish and do the laundry.

Besides..guests insist that certain ports are visited and with many of these must visit ports, anchoring is out of the question. Im in port now..outside the harbour entrance its 75 meters deep, 20 knots of wind and one meter swells. Guests are ashore...enjoying life. Im charging and running the ship on 16 amp shorepower . Ahhhhhhh

 

Well, I'm not. It's a obviously a giant waste of your time. Just look at the results - you ask for help in selecting and sizing your electrical propulsion system and you get SIX PAGES of posts mostly trying to convince you that inboard diesel is the only way to go. Certainly no solid leads in helping you answer your original questions.

That's boating folk for you. Diehard traditionalists. You can dress them up but can't take them anywhere.
(yeah, I know, someone will pop up and say "we're just realists".... Right.)

BTW, don't waste more of your time with ASMO, they don't have submersibles. They do have a fine and apparently reliable system that uses the Lynch pancake motor. What's more, it's reasonably priced. However, it's inboard only.

 

Thanks, Injuneer. I think you're probably right. Funny thing is, these systems are used all over the place except in pleasure boats. It's pleasure boaters that don't accept them. Oh well... I think I may have to agree with you here. Hey, you aren't an industrial or electrical engineer (with advice on where to find good VFD's and AC motors) are you?

Ok, Michael... I'll answer you below, in red...