Cruisers Forum
 


Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 03-02-2020, 17:35   #91
Registered User

Join Date: Jul 2019
Posts: 301
Re: Replace Diesel with electric engine

Quote:
Originally Posted by stormalong View Post
And, for the record I own a Tesla and love it. I also have a land based infrastructure to support it. That just does not exist for electric propulsion in the cruising world and anyone going down this path needs to understand this.
Forty years from now? Probably.
Poche is offline   Reply With Quote
Old 03-02-2020, 19:46   #92
Registered User

Join Date: Mar 2013
Location: Slidell, LA
Boat: Beneteau First 375
Posts: 449
Re: Replace Diesel with electric engine

Quote:
Originally Posted by Adelie View Post
Why would I believe that? I didn’t write anything about trolling motors in my post about the Cal 34. Did you not closely read my post or was that a rhetorical device attempting to put words in my mouth?

I posted that the motor vendor I’d dealt with indicated 960w could likely push the boat at 3.2kt. I thought it would be more like 1,000w for 3kt.

Implicit in my post, like the thread in general, is the replacement of the boat’s fuel motor with an electric motor. As such the motor would be turning the normal propellor for such a boat and thus would have significantly higher efficiency than a trolling motor.
Sorry, I wasn't trying to put words in your mouth. What I meant was, a typical trolling motor runs about 750 watts, or 1 HP. Some of the largest ones approach 1 KW. 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.

Many people claim that somehow 1 HP from an electric motor drives a boat twice as well as 1 HP from a diesel motor. From a physics standpoint, that is just wishful thinking. Yes, at low RPMs the torque from an electric motor will be higher than a diesel, but at higher RPMs, when you are trying to get to 3 knots, everything equalizes. Can your vendor provide you with real-world examples of their installations meeting their performance claims?
sandy stone is offline   Reply With Quote
Old 03-02-2020, 21:13   #93
Registered User
 
Ken Fry's Avatar

Join Date: Dec 2019
Location: Atlanta, on way to NC coast
Boat: Custom 31' rigid wing cat
Posts: 224
Re: Replace Diesel with electric engine

Quote:
Originally Posted by sandy stone View Post
Many people claim that somehow 1 HP from an electric motor drives a boat twice as well as 1 HP from a diesel motor. From a physics standpoint, that is just wishful thinking.
True, at least in one very limited sense. Such claims bug me too.

Just as do claims of 5 hp from a shop VAC that plugs into a standard outlet: obviously impossible. 15 amps x 120 v is less than 5 hp.

A one hp continuous rated electric motor cannot supply 2 hp for 24 hours at a time, and still live as long as its design life. Of course such a motor can typically produce small to large multiples of its continuous rating. How hot do you want it to be? How long do you want it to last?

I noticed that I have several of the electric motors that appear to be used on some of the Oceanvolt systems in my shop. In the motorcycle conversion world, they are considered 30 kw. (40 hp) And they can produce that for a few seconds before they glow red hot. (Actually for about a minute.) Oceanvolt rate the AX3 at 3.7 kW, which is a very very conservative rating for that motor. They could correctly claim that the motor can produce 40 hp, briefly. They could also claim that the motor can produce 80 hp for about a second.

But more reasonably, they can correctly say that the motor can produce 10 kW for plenty long enough to maneuver, or claw off a lee shore, etc.

(In my tiny hybrid car (three wheeled, so technically a motorcycle) I used one of these motors -- actually an earlier, cruder version -- and it caused the car to perform as a 40 hp gas engine would, although without the charming noise and smoke and smell.)

Diesels (and car engines, etc.) are rated for their peak power. Electric motors are rated (typically in the marine world and in industrial applications) at their continuous rating (and at all sorts of other ratings in other sectors... thus the impossible 5hp shop vac.) So a three-to-one multiplier is not unreasonable, although it is often not as clearly explained as it should be. Oceanvolt's 3.7 kw (about 5 hp) motor produces 40 hp in my application. So I would be last person to suggest they are somehow cooking the books by using a 2:1 or even 3:1 multiplier. My experience proves 8:1.

Looked at another way: There is nothing special about a Tesla motor -- they are wound with copper, just like any other motor. Static air cooled and in an industrial application, such a motor would be rated at 30 - 40 hp (or less... they are only 75 lb or so, after all.) (My lathe motor is only one hp and is 30 lb) But in an automotive application, they are rated at over 200 (with water cooling and well-designed controls to reduce that power when they get too hot.)

For decades, electric car enthusiasts have been doing 10 second quarter miles using fork lift motors originally rated at 15 hp.
Ken Fry is offline   Reply With Quote
Old 04-02-2020, 02:11   #94
Marine Service Provider

Join Date: Feb 2012
Location: Vienna, Austria
Boat: Vagabond 47
Posts: 929
Re: Replace Diesel with electric engine

Half a year ago I did a calculation for my 20 tons 47ft Vagabond:


https://www.elcomotoryachts.com/prod...ctric-inboard/

= 25.000 USD

Genset
https://www.seapowermarine.com/produ...round-1-phase/
= 16.300.--
Battery Lifecycle 5 years
EP-12 Victron AGM Deep Cycle 12V/220Ah (9x) (+$5,409.00)

= 1081,80 USD per year
-----------------------
I fuel up around 200 L Diesel per year, = 400 USD (EU-Prices)
-----------------------
so: one have to plan the investment with around 45.000,-- USD


Some Data:
Cruising range*36 – 20 nm on batteries only
Kilowatts (continuous output kW rating)29.75 kW
Battery bank voltage in total108 vdc (more than 36V are considered as DANGEREOUS)

Genset Diesel consumtion around 3,5 - 4 L /hr
My old Ford Lehman 85 hp is 5,5 L/hr
a compete refurbishing is around 6000 USD
a new engine (never ever!) would be around 18.000 USD
Electric propulsion with Genset 45.000 USD

Sorry but for me Electric propulsion is out of discussion.
moseriw is offline   Reply With Quote
Old 04-02-2020, 03:02   #95
Registered User

Join Date: Jan 2014
Posts: 3
Re: Replace Diesel with electric engine

Are you on the Amel Forum (amelyachtowners.groups.io)? What they don't know about tricking out Amels isn't worth knowing!
Tubbs is offline   Reply With Quote
Old 04-02-2020, 04:42   #96
Registered User

Join Date: Feb 2013
Location: NH
Boat: sabre 28
Posts: 283
Re: Replace Diesel with electric engine

FWIW I can motor my 28 Sabre at 3-3.5 knots & consume 15 amps/700 watts out of my 48 volt battery bank. That works out to 1 HP.
__________________
I'm not happy unless I'm complaining about something. I'm having a very good day!
misfits is offline   Reply With Quote
Old 04-02-2020, 05:15   #97
Senior Cruiser
 
skipmac's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Location: 29° 49.16’ N 82° 25.82’ W
Boat: Pearson 422
Posts: 16,306
Re: Replace Diesel with electric engine

I could not agree. All these points are exactly the same ones I've tried to make many times.

Quote:
Originally Posted by PSea View Post
I find many of these arguments against electric drives red herrings. Here's how i look at it. For someone that is just a day sailor, it could make a lot of sense just using it in and out of the harbor. For cruisers, there's a grey area imo.

For day sailors or anyone else who never uses a motor for more than a few miles electric could be great. For some cruisers going electric may be a grey area, for many I think it's clearly black and white.


For the cruiser that intends to have a diesel engine and a generator, I don't see how you can lose. Generators are far more efficient at charging batteries vs the engine. Second, going electric would cut the number of diesel engines you have to maintain by half. The added bonus is once in a while you can pull into port or leave the dock on battery alone.

Exactly! Electric with a generator solves the issue of range but at a cost. To add a generator that can supply full power to the electric for those times when you need full power the cost will be double or triple the cost of going direct diesel engine for power.


You don't install electric for range. You install a generator for range. You get the added benefit of a hydro generator which is nice to use, especially overnight as your making way.

For those that would cruise without a generator, I think e-propulsion is a tougher proposition.

Now, in situations where the motor isn't strong enough or parts are hard to source, this isn't an industry problem. That's a vendor problem. I'm sure some experience the same problems with other parts on their boats.



I love the idea of electric propulsion. It's well proven. I despise the fact that the companies selling it are gouging people heavily. The prices they're charging are absurd.

Another issue I've mentioned many times. The price for "marine" electric motors is outrageous. Larger motors in the 25-50 kW range list for tens of thousands of dollars. Same power industrial electric motors with same ratings for peak and continuous power $1,000-$2,000. So maybe the "marine" units have a few SS bolts but for what they sell for I could buy 2-3 industrial motors so have spares and thousands left over. Asked this question many times and have never gotten any kind of answer as to why the huge price disparity.

__________________
The water is always bluer on the other side of the ocean.
Sometimes it's necessary to state the obvious for the benefit of the oblivious.
Rust is the poor man's Loctite.
skipmac is offline   Reply With Quote
Old 04-02-2020, 05:18   #98
Senior Cruiser
 
skipmac's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Location: 29° 49.16’ N 82° 25.82’ W
Boat: Pearson 422
Posts: 16,306
Re: Replace Diesel with electric engine

Quote:
Originally Posted by moseriw View Post
Half a year ago I did a calculation for my 20 tons 47ft Vagabond:


https://www.elcomotoryachts.com/prod...ctric-inboard/

= 25.000 USD

Genset
https://www.seapowermarine.com/produ...round-1-phase/
= 16.300.--
Battery Lifecycle 5 years
EP-12 Victron AGM Deep Cycle 12V/220Ah (9x) (+$5,409.00)

= 1081,80 USD per year
-----------------------
I fuel up around 200 L Diesel per year, = 400 USD (EU-Prices)
-----------------------
so: one have to plan the investment with around 45.000,-- USD


Some Data:
Cruising range*36 – 20 nm on batteries only
Kilowatts (continuous output kW rating)29.75 kW
Battery bank voltage in total108 vdc (more than 36V are considered as DANGEREOUS)

Genset Diesel consumtion around 3,5 - 4 L /hr
My old Ford Lehman 85 hp is 5,5 L/hr
a compete refurbishing is around 6000 USD
a new engine (never ever!) would be around 18.000 USD
Electric propulsion with Genset 45.000 USD

Sorry but for me Electric propulsion is out of discussion.
I have done the same calculations many times and compared prices from a number of different marine electric suppliers. Always come out with the same answer as you. Going electric power with a generator to give a longer cruising range is double or triple the cost of a traditional diesel engine.
__________________
The water is always bluer on the other side of the ocean.
Sometimes it's necessary to state the obvious for the benefit of the oblivious.
Rust is the poor man's Loctite.
skipmac is offline   Reply With Quote
Old 04-02-2020, 06:49   #99
Registered User

Join Date: Dec 2014
Location: On a sphere in a planetary system
Boat: 1977 Bristol 29.9 Hull #17
Posts: 730
Re: Replace Diesel with electric engine

The technology for electric propulsion in recreational yachting is not ready for prime time, it’s not that’s its a bad idea, it’s just not as useable and dependable as a Diesel engine with an Alternator, and a little bit of solar, the diesel just flat out out performs the alternatives currently available, jmo.

Fair winds,
Pegu Club is offline   Reply With Quote
Old 04-02-2020, 07:35   #100
Registered User
 
GrowleyMonster's Avatar

Join Date: Dec 2012
Location: New Orleans
Boat: Bruce Roberts 44 Ofshore
Posts: 2,907
Re: Replace Diesel with electric engine

Quote:
Originally Posted by boat_alexandra View Post
Wow, a lot of negative remarks against electric that do not help or answer the OP's questions.

People end up on rocks because of poor navigation not because of lack of engine power. Many risks are taken because of the engine and trusting electronic navigation systems too much.



Been in these scenarios and worse and always managed to avert danger using sail alone. A lot of boats lost because the owner tried to use the engine rather than raise the sail.

Even better, don't be in those scenarios. It can be pretty hard sometimes to get where you want to go, though, if you always plan your voyage as if you had no engine. You do have a point, though.


Quote:
For the US ICW. You do not need any power besides sail. An electric motor may be convenient but not required.

On much of the ICW, this can be difficult, especially if you take to heart the part of the rules that say you shall not impede. Wind force and direction doesn't always allow you to sail outside the bouys on a nice easy run or reach. You still need mechanical propulsion at least some of the time. So an EP system should be designed around those demands if ICW cruising or similar is anticipated.


Quote:
Since there is a propeller shaft in the boat with nothing attached, I'm putting in an electric drive for fun to see what it can do. I already have all the parts. The motor cost $50 (free shipping) is 2800 watt brushless motor with rare earth magnets. The gear reduction using chain and belt (2 stage) This cost $30 in total because you can 3d print the pulleys. The controller cost $23 on ebay, and it uses 24 volt 40ah lithium iron battery cost $600. Will be interesting to see the performance, it is likely 3-4 knots speed and 10-12 miles going slowly with 250 watts solar to recharge.

Please, no. Don't try to use plastic pulleys. And that $23 controller believe me is not up to the task. Ratings are what the mfgr says they are, and are shall we say, a bit optimistic. You would want to carry several spares. My recommendation is a nice Kelly pure sine wave controller. Remember controllers are rated for PEAK current, not sustained. So remember this when I tell you that a 300A controller is about the minimum you would want, and that is at 48v.



This is your Bristol 27? TBH you really need a 5kw motor with a proven track record. And in fact I would go with a 10-12kw motor. The bigger motor offers very little extra parasitic load, unlike going up in size in a diesel. The bigger motor will have better heat dissapation. It will almost always be just loafing along. Bad for diesel. Good for electric. BTW rare earth magnets are almost universal in PMAC/BLDC motors.


I advise against chain drive. Belt is quieter and less messy. How many EP boats have you seen with chain drive? I considered it and discarded the idea for my Cal 2-27.



40ah 24v would be perfect for powering a stand up paddle board. You want any reasonable performance level, you want at least 200ah at 48v. A single series of GC2 golf cart batteries worked okay for me, at very low cost. Just for fun though, I ran the boat once on a 20ah 48v ebike battery and got something like 3 miles range out of it at a couple of knots. Same watt/hours as your 24v 40ah battery. Similar size boat. Going really slow on a calm evening on Lake Pontchartrain, so no current and basically zero wave action. No sails up.



Go 48v. Half the current to do the same work. Lower line losses and lower copper losses in the motor. Higher voltage is more efficient. You just don't want to be over 50v due to getting into what is regarded as "lethal" voltages and a different set of electrical standards. Up to that mark, higher voltage is better.



The biggest mistake most EP zealots make is overestimating the performance levels of their intended system. Unless it is just for docking, you want a substantial bank. And you want a bigger and proven motor and controller setup.



Quote:
You can choose how you generate the energy to charge your batteries.


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.

Just don't expect it to hold up very long in an offshore passage. Well, or an inshore passage LOL! In a fight with a log or rock or crab trap even, it will probably lose. Notice how well the prop is protected. The same size prop with variable pitch can be configured efficiently for propulsion at various speeds, and for regen. Your 16"er in theory will work pretty good, but might be a bit big for that boat.



If you are an old hand at in-the-water prop changes, you might want to try 3D printing your prop. Experiment with different pitches for propulsion and regen, and tip clearance. You can probably optimize your prop a good bit, and possibly have one fixed pitch prop for when you are mostly concerned with propulsion efficiency, and another when you care more about regen efficiency. BTW you will probably be disappointed with how much charge you get from regen at the typical sailing speed of a 27' keel boat. And you can expect to lose probably 1/4 to 1/2 kt from the prop loading, vs allowing it to spin free. Regen truly comes into its own when you are regularly and consistently logging 10kts or better.


Solar is great but crowding on enough panels to seriously charge your bank will be awkward. Be careful you are not being overoptimistic in view of the short time in the day when you get optimum performance from them, and the shading of mast, sails, even rigging.



For day sailing, EP is great! You would love it! With the right charger setup, shore power charging overnight is easy sneezy. No trips to the fuel dock. No spills. Nearly silent in a good installation. Instant on, no warmup. No minimum idle speed. Crazy torque when you want it. Simple, no cooling system or exhaust system. And you don't NEED solar or regen or a generator.


For cruising, you would want all the solar you could fit for nice weather, and ability to remove and stow vulnerable panels for bad. You need all the power you can get to get and keep your bank charged, so the little bit of regen you can make is important, so a regen optimized prop on passage, or a variable pitch prop. And yeah, you really should have at least a 3.5kw diesel genset. You never know when you will want the longer legs of a diesel prime mover. I have used a portable gasoline generator in the cockpit just as a get home backup, but this was inland or inshore weekending or day sailing. And I knew how to engineer the charging system for optimal performance, and how to safely monitor it. The problems of a gasoline portable genset on a passage are obvious.


Wind charging can nearly be eliminated. To get a full kw consistently you would need about a 10' dia turbine. I didn't believe it until a very knowledgeable engineer showed me the figures. A 300w turnkey setup seldom actually delivers 300w. Worth considering if you spend a lot of time anchored, maybe. Some are more quiet than others.



Often you can get a measure of how practical something is by looking at how many people use that particular something. Being in the early adopter crowd often puts you in the situation of making excuses for poor performance of you wondrous new system. It fosters am unwillingness sometimes to accept reality.



Cruising with EP can be done, obviously. It has been done and it is being done. But the system needs to be well optimized and needs to be a good fit for owner/skipper/crew, the boat, and the intended cruising grounds and style. A lot of compromises have to be accepted regarding speed/range/bank size and charging needs. Day sailing with EP is a perfect fit for most small or medium size boats. Larger boats as in over say 10 tons pretty much demand automotive motors, controllers, and very large banks with sophisticated BMS. Higher voltages make higher technical demands of the operator.



Quote:
As for friction it is critical. Most diesel designs do not consider efficiency as a primary objective and it is questionable if you should use existing propellers drive trains or sail drives unless you want to sacrifice large losses.

Most cruising boats have less than 20% efficiency from shaft to propulsion due to a small diameter propeller (<2ft) torqueedo claims 54% efficiency but this is a best case not usually achieved. Specially designed solar boats can achieve 80% or better. A well designed wooden sculling oar is around 85% efficient.


ie: never


Diesel is ok by me if you never use it.

Sculling oar? I somehow doubt that efficiency claim, but 1/10 HP at 85% is still not very powerful or sustainable for long periods. Yeah, diesels are ICE and ICE are not very efficient, especially with any sort of convoluted drive configuration, and props are not designed purely for efficiency, either. The low efficiency of a diesel is offset by the power density of the fuel. And don't overestimate EP efficiency, either. Diesel isn't dead and won't be for the foreseeable future. If you really want a great system for cruising and you really want to stretch your engineering wings, look into a parallel hybrid system with a very small Kubota diesel, a 10kw brushless motor and 500A controller, belt reduction, 48v bank of GC2 or L16 batteries, variable pitch prop, and all the solar you can comfortably carry. This is a fairly complex setup and any operator really should be a pretty fair engineer to properly understand what is going on with the system at any given time of a watch.


For cruising, a straight diesel drive is still the most practical setup you can have. For most sailors anyway. Leave the thundering herd at your own risk. Maybe the adventure will be worth it. But not with the system you are contemplating. For day sailing in and out of a marina with shore power available at your slip, you still want a more substantial motor/controller/battery setup but it is if anything, BETTER than diesel.


Been there, done that. I even tried pushed my boat around a bit with a $100 trolling motor LOL! I also deliberately overvolted it and the darn thing literally exploded underwater which was actually more kewl than disappointing. I used one of those cheapie Chinese ebay electrobike controllers you are talking about, BTW. I have done some crazy stuff, yeah. I am not what you would call a conservative or conventional engineer and I don't have a degree and I don't have a problem with questioning conventional wisdom. And yet, my experiments and experiences keep leading me at least partially back to the road more traveled. But your boat, your life. I totally understand your daedalusian fantasy of EP for the price of a night out on the town. My advice though, is to look at what other folks are using successfully, and carefully examine the performance tradeoffs that they are dealing with. Temper your adventurism with the reality that you find and don't try to repeal the laws of physics. And don't believe everything you read on ebay product listings.
__________________
GrowleyMonster
1979 Bruce Roberts Offshore 44, BRUTE FORCE
GrowleyMonster is offline   Reply With Quote
Old 04-02-2020, 10:56   #101
Moderator
 
Adelie's Avatar

Join Date: Feb 2010
Location: La Ciudad de la Misión Didacus de Alcalá en Alta California, Virreinato de Nueva España
Boat: Cal 20
Posts: 20,638
Re: Replace Diesel with electric engine

Quote:
Originally Posted by sandy stone View Post
Sorry, I wasn't trying to put words in your mouth. What I meant was, a typical trolling motor runs about 750 watts, or 1 HP. Some of the largest ones approach 1 KW. 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.



Many people claim that somehow 1 HP from an electric motor drives a boat twice as well as 1 HP from a diesel motor. From a physics standpoint, that is just wishful thinking. Yes, at low RPMs the torque from an electric motor will be higher than a diesel, but at higher RPMs, when you are trying to get to 3 knots, everything equalizes. Can your vendor provide you with real-world examples of their installations meeting their performance claims?


Yeah, I really do think a Cal34 could get close to 3kt with 1kW electric.

I have a Cal20. 17mo ago I tested speed and bollard pull for a 4-1/2hr outboard and a 30lb thrust trolling motor.

4.5hp (WOT): 5.0kt 36kg bollard. 3357w.
Trolling: 2.35kt 9kg bollard, 30a or 360w.
So 9x the power to get 4x the bollard pull and just over twice the speed.

I’m not very confident in the absolute values for the bollard pull but the relative values I’m confident in.

My boat is 18’ LWL and 2040lb light so let’s say 3,400lb (1.5LT) loaded.
Using Skene’s graph I was using 240w/LT at .55 SLR.

Down-thread Misfit got 3.0-3.5kt (let’s say 3.2) for 700w.
Sabre 28: 7400lb lightship for lightest model, let’s say 8500lb (3.8lton) tested, with an lwl of 22.8’.

Using Skene’s graph misfit was using 184w/LongTon at an SLR of .67.

Sail Today in Jul2012 published a thrust comparison for 7- 10hp outboards and a Torqueedo 4T-R, (2,200w).
One of the gas motors was de rated to 8hp and one was a high thrust model though there wasn’t a discernible impact on thrust for either. The outboards had 82-94kg thrust (median was 88kg or 194lb). The Torq had 100kg (220lb).

Another test I found showed 3.5hp outboards delivering about 90lb, 2.5hp delivering about 75lb and the Honda 2.3 giving 66lb. .

The thing is with electric motors a lot of thing change compared to fuel motors, low end torque, rotational speed and prop dimensions being the 3 biggest the way I see it

Attachment 208134
__________________
Num Me Vexo?
For all of your celestial navigation questions: https://navlist.net/
A house is but a boat so poorly built and so firmly run aground no one would think to try and refloat it.
Adelie is offline   Reply With Quote
Old 04-02-2020, 13:40   #102
Registered User
 
StuM's Avatar

Cruisers Forum Supporter

Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43 and OPBs
Posts: 12,891
Re: Replace Diesel with electric engine

Quote:
Originally Posted by GrowleyMonster View Post
Well, that was certainly an interesting read, and a different viewpoint. I think.

I'll have some of what he's on
StuM is offline   Reply With Quote
Old 04-02-2020, 13:48   #103
Registered User

Join Date: Apr 2011
Location: San Francisco and Massachusetts
Boat: FP Athena 38, Catfisher 28
Posts: 34
Send a message via AIM to MichaelPrichard Send a message via Skype™ to MichaelPrichard
Re: Replace Diesel with electric engine

A well designed series hybrid drivetrain (which the OP appears to have proposed) can be an exact match or superior to any diesel-only solution. The on board generator does NOT need to be sized to provide 100% the power output of the motor as that's why one has the batteries. Almost all hybrid cars operate with lower powered, smaller gas engines as they use the batteries to provide launch power and hill climbing assistance. So, too, do the batteries in a series hybrid sailboat, with the added advantage of being able to provide that power RIGHT NOW while the glow plugs for the diesel are still warming up.

On top of this, electric POD drives eliminate all gearing so that the entire electric side of the system has only the one moving part, which for most POD drives should easily outlast the boat. Gone are the clutches, reversing gears, shift cables, gear oil (not all motors), and even cooling since most sub-10kW POD drives get all the cooling they need by simply being submerged in seawater. This may be where many are noting the improved power delivery of electric toward thrust over diesel.

I'm 80% of the way through converting my Fountaine-Pajot Athena 38 catamaran to twin retractable 7.1kW E-Tech POD drives powered by a 10.6kWh Tesla battery (using 2 used Model S modules) managed by a REC-BMS which fully controls charging via Victron 5kW Quattro and solar MPPT. Due to catastrophic sail drive electrolysis damage caused by yours truly, I was looking at a $19k replacement cost which would've left me with the same tired 2GM20F Yanmars and constant worry over raw water intake occlusion, diesel filter clogging, water pump">raw water pump impeller state, smell in master cabin (engines mounted below rear berths in Athena), vibration, noise and fumes when motoring back to marina, usually downwind with diesel exhaust wafting across cockpit. The engines have been a constant barrier to sailing due to their age and the fact that none of my friends/family are diesel mechanics, so no one is comfortable sailing if I'm not on the boat. Ripping apart the master cabin to do routine (but required) checks added to the high activation energy.

Since we have only ever used our boat sailing around the SF Bay Area, we don't even need a generator for now since we really only need 10NM range, although predicted range may exceed 25NM with just 10.6kWh if the motor reps data are accurate, and this is ignoring any regen we will hopefully also benefit from. My hulls no longer have any thru-hulls except for the water maker and HVAC, nor any metal hanging in the water except for the ground plates and tiny bit of rudder shaft. Easier retractibility (with no gearing) is something that only electric POD drives offer; there's no diesel equivalent. Sailing with no sail drive leg, or props in the water should be great. Always having clean props is a huge advantage of retractability, as is the simplicity of a very cheap but efficient and aggressive 3-blade prop ($300-400 vs. $5k+ for folding/feathering advanced prop). Not having to take a swim to un-foul the prop is also a big win.

Eventually, as we get a feel for the performance of the boat with just 10.6kWh of storage, we'll likely add more battery and possibly some form of fossil fuel power generation (hoping fuel cells get better...) as we plan for longer voyages, but even a 5kW generator would likely keep our boat moving at 5kt cruising speed indefinitely, and that can be located anywhere with much better vibration isolation than a hard shaft connected diesel. We're currently around 800lbs lighter due to the removal of around 2 x 400lbs engines/saildrives and 380lbs for 40gal fuel tank not to mention miles of piping, hoses, battery starter cables (12V) and associated support pieces. Added back are 2 x 55lbs POD drives, 2 x 56lb Tesla battery modules and around 120lbs of new 316 stainless custom retractible drive legs (mounted under bridgedeck).

There are admittedly limited numbers of vendors supplying electric power trains for boats right now, just as there were only 2 manufacturers (Toyota and Honda) of hybrid cars in 2001, but that "experiment" clearly proved successful as 1 in 5 cars on the road now seems to be a Prius and probably 80-90% of uber/lyft drivers and taxis have switched to hybrids for drastically improved efficiency, reliability and longevity. Electric propulsion is simply superior in terms of power density, control, smoothness, simplicity and longevity, and the drawbacks in range can be mitigated in the short term via hybridization. I find that wire, connectors and even computers are far "simpler" than the incredible complexity of the modern diesel. More and more these systems can self-identify faults and guide one toward repairs (not quite as good as it should be yet, admittedly). Having spares for a longer voyage will likely be similar to the old diesel days, just with different choices of hardware. I can even carry an entire "spare" POD drive, for instance, if I'm willing to fork over another $6.5k, but it's tiny and only weighs 55lbs.

So, when it comes to which propulsion system you'd rather have when bearing down on a lee shore in bad weather, I'd recommend one that's currently working... That has not always been true of my twin 25 year old Yanmars, but luckily I've had 2 of them; it may not always be true of an electric system either, but proper care of either should keep you off the rocks. In the meantime, the other 99.999% of my time on the boat will be spent with silent propulsion that removes all drag while sailing at the turn of a key with the option of recharging the batteries on long sails, enjoying HVAC anywhere, induction cooking and no propane.

I plan on a longer description of my project along with any design files other catamaran owners might be interested in when I'm done. I'm cautiously optimistic about some of the performance predictions but also trying to maintain a healthy skepticism about some of the hype.
MichaelPrichard is offline   Reply With Quote
Old 04-02-2020, 15:39   #104
Registered User
 
CarinaPDX's Avatar

Join Date: Jan 2010
Location: Portland, Oregon, USA
Boat: 31' Cape George Cutter
Posts: 3,291
Re: Replace Diesel with electric engine

Comparing electric/gas cars to electric/diesel boats is problematic. Hybrid cars like the Prius have a great advantage in stop-and-go city driving due to the energy recovery. On the highway their advantage is much less; they are only slightly more efficient than a similar-sized gas car, where the hybrid's smaller engine gets passing power through electric motor augmentation. A boat is an entirely different matter - when under power there is an approximately constant power output. If we are talking about powering for hours the batteries cannot add much to the generator output for supplying the motor. Designing a cruising boat's propulsion for only brief periods of full output is fine for local sailing but not for long range cruising as most cruisers use their boats. If you have a 5kW genset then your motor will have a 5kW sustained output, with battery-augmented operation to the motor's 7.1kW output for a few hours (assuming your control system can stop the genset from charging the batteries when that extra power is needed). If that is enough for your usage pattern then go with it. Assuming you have the extra money to spend. Also, don't fool yourself into thinking this is a green solution - it isn't. From the extra manufacturing energy, the conflict minerals, and the lack of recycling for Li-ion batteries this isn't even close to being green yet, if ever.

Greg
CarinaPDX is offline   Reply With Quote
Old 04-02-2020, 16:17   #105
Registered User
 
Ken Fry's Avatar

Join Date: Dec 2019
Location: Atlanta, on way to NC coast
Boat: Custom 31' rigid wing cat
Posts: 224
Re: Replace Diesel with electric engine

Quote:
Originally Posted by Balidur View Post
|> |> |> |> |> |> |> |>
|> |> |> |> |> |> |> |> |>


Say thank you to your governments which hold that secret and killed nearly all which want build or created masxproduction ready devices...

|> |> |> |> |> |> |> |>
|> |> |> |> |> |> |> |> |>
Can you suggest the best name and address for the thank you note? Should it be to someone in local, state, or national government?

You will be happy to know that Dennis Lee, the most famous scam artist who promoted a perpetual motion generator/motor combination and a very slick mass production ready "HHO" unit, has NOT been killed. He was convicted of fraud regarding the perpetual motion device. Nevertheless, that first famous scam was successful enough (in financial terms)* that he was able to move on to his next gullible marks with the "HHO" units. That, too, got shut down for fraud, but he has not been killed.

So take heart: at least in the US, fraudsters do not routinely get killed. You will be happy to know that I helped the FTC prosecute the Lee HHO issue, in a small way. They lost in court the first time around, Dennis being one slick fella. The FTC key witness was a highly-regarded physicist from Northwestern Univ, if i recall, who spoke in perfectly accurate and reasonable physics terms. The judge however, who was not a physics wizard, made the valid legal point that the FTC did not demonstrate that the unit (about $.75 worth of metal and plastic in a powerfully cute shape selling for something like $1500, if I recall) DOES NOT work, but only than it CAN NOT. So I called the FTC Attorneys to give them the name of a guy at MIT who could do the necessary dyno testing to show that Lee's HHO unit not only could not but DID NOT work.

You will probably thank me for helping (in a small way) convict Lee, because some of the people who had been bilked by him felt that they had at least seen some justice done. Otherwise, some of these folks, most of them hard-working souls without the cash to by a Prius (to get real fuel efficiency improvements), might otherwise be inclined to kill Lee. You can think of me as one of Lee's life savers, if you would like. I would have liked to see him go to jail, but he did not. He would have been even safer there... and even less likely to continue to harm the lives of decent (albeit woefully uninformed) people.

I love the decoration of your post, by the way. ^^^^ %%%% ###


*(and woefully unsuccessful in ethical and moral terms)
Ken Fry is offline   Reply With Quote
Reply

Tags
diesel, electric, engine

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Any Merit in Subdividing the Engine Subforum into Diesel / Gas and Electric / Hybrid? David_Old_Jersey Engines and Propulsion Systems 8 17-02-2020 06:41
Diesel vs Electric Engine MoxieGirl Electric Propulsion (EP) 81 16-08-2018 15:42
Lines - To replace, or not to replace? TooCoys General Sailing Forum 31 25-04-2017 13:32
Electric Fuel Pump for Diesel Engine onestepcsy37 Engines and Propulsion Systems 9 20-10-2010 05:42

Advertise Here


All times are GMT -7. The time now is 03:13.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.