Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 21-08-2015, 06:55   #31
Registered User
 
micah719's Avatar

Join Date: Jul 2012
Location: Somewhere in Germany
Boat: OEM, proportional
Posts: 1,436
Re: Electric Inboard

Quote:
- could be left with no power in a critical situation. What do you do if you have run to max range, batteries flat and you have to move the boat for some emergency?
This puzzles me. One of the significant benefits of electric drive with a battery is that it is available instantly; no starting problems or warm-up, and it won't choke on crud that may be stirred up in rough conditions. How far would you need to move in an emergency, and for how long? The battery will be enough to move out of the path of oncoming vessels and maneuver short term, and the generator and panels are for range...I'd strike readiness in emergency of electric off the negative list for electric.

Also, I looked at an Elco motor recently; sealed AC brushless which is submersible and requires bearing service after 50,000 hours. Electric isn't for everyone, but the folks that have it seem to be very happy...
__________________

__________________
Ps 139:9-10 If I take the wings of the morning, and dwell in the uttermost parts of the sea; Even there shall thy hand lead me, and thy right hand shall hold me.
micah719 is offline   Reply With Quote
Old 21-08-2015, 07:04   #32
Registered User

Join Date: Apr 2013
Posts: 4,877
Re: Electric Inboard

Quote:
Originally Posted by micah719 View Post
This puzzles me. One of the significant benefits of electric drive with a battery is that it is available instantly; no starting problems or warm-up, and it won't choke on crud that may be stirred up in rough conditions. How far would you need to move in an emergency, and for how long? The battery will be enough to move out of the path of oncoming vessels and maneuver short term, and the generator and panels are for range...I'd strike readiness in emergency of electric off the negative list for electric.

Also, I looked at an Elco motor recently; sealed AC brushless which is submersible and requires bearing service after 50,000 hours. Electric isn't for everyone, but the folks that have it seem to be very happy...
If you treat your diesel poorly such that you can't rely on it starting...I would assume you would do the same with an electric system and it also would be unreliable. I hit the key and the motor starts. Having the engine in gear and pushing within 5 seconds is very realistic and done once in a while is pretty harmless.

As stated, if you just ran your batteries down and a squall comes thru that lasts 1/2 hr and you need to give it a lot of throttle to hold in place, the batteries could easily run out on a pure electric system. If you do a diesel electric system that issue goes away, as mentioned previously, it's cheaper and more efficent to just run a straight diesel system.

The people who are "happy" usually are die hards that want it to work regardless of the facts so I take thier statements of happieness with a big grain of salt. Also most are home built systems by guys who can do all the work themselves. Moving it to a retail plug and play system is a whole different world. My assumption is anyone coming to a forum to ask if it makes sense doesn't have the background to build thier own system.
__________________

__________________
valhalla360 is offline   Reply With Quote
Old 21-08-2015, 07:38   #33
Registered User
 
micah719's Avatar

Join Date: Jul 2012
Location: Somewhere in Germany
Boat: OEM, proportional
Posts: 1,436
Re: Electric Inboard

Quote:
Originally Posted by valhalla360 View Post
If you treat your diesel poorly such that you can't rely on it starting...I would assume you would do the same with an electric system and it also would be unreliable. I hit the key and the motor starts. Having the engine in gear and pushing within 5 seconds is very realistic and done once in a while is pretty harmless.

As stated, if you just ran your batteries down and a squall comes thru that lasts 1/2 hr and you need to give it a lot of throttle to hold in place, the batteries could easily run out on a pure electric system. If you do a diesel electric system that issue goes away, as mentioned previously, it's cheaper and more efficent to just run a straight diesel system.

The people who are "happy" usually are die hards that want it to work regardless of the facts so I take thier statements of happieness with a big grain of salt. Also most are home built systems by guys who can do all the work themselves. Moving it to a retail plug and play system is a whole different world. My assumption is anyone coming to a forum to ask if it makes sense doesn't have the background to build thier own system.
Full throttle from cold is not good for the engine. The electric system is much simpler and has less to go wrong. Murphy likes to stow away for those exciting moments. The people who are happy with electric are those who have made it work for their needs; as I said, it isn't for everyone.

Nobody is born with the knowledge and skills to make it work, they all have to learn. I'd suggest anyone simply seeking plug'n'play solutions is in for an expensive and frustrating ride, especially as a "cruiser", whatever that is. This is one place to start learning, though it is difficult with folks that seem to specialise in trying to shoot other's dreams and hopes down in flames without addressing the reasons why someone may prefer doing something different, or helping them.

Look around CF at the things that folks consider the negative experiences of cruising, and how many of these things relate to engines and electrics. The real problem is, we're using a patchwork of solutions that others developed under pressure from markets and cultures; the thread holding the quilt together is money, and sleeping under it is stressful. From what I've learned from the electric boat people, they're happy and their solutions work for their needs and circumstances; that doesn't mean they're suggesting a blanket diktat for everyone else to do what they're doing.

With research and study an affordable and convenient electric solution is achievable, and the compromises in range and cost are acceptable given the other advantages gained.
__________________
Ps 139:9-10 If I take the wings of the morning, and dwell in the uttermost parts of the sea; Even there shall thy hand lead me, and thy right hand shall hold me.
micah719 is offline   Reply With Quote
Old 21-08-2015, 07:44   #34
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: 12,374
Re: Electric Inboard

Quote:
Originally Posted by micah719 View Post
This puzzles me. One of the significant benefits of electric drive with a battery is that it is available instantly; no starting problems or warm-up, and it won't choke on crud that may be stirred up in rough conditions. How far would you need to move in an emergency, and for how long? The battery will be enough to move out of the path of oncoming vessels and maneuver short term, and the generator and panels are for range...I'd strike readiness in emergency of electric off the negative list for electric.

Also, I looked at an Elco motor recently; sealed AC brushless which is submersible and requires bearing service after 50,000 hours. Electric isn't for everyone, but the folks that have it seem to be very happy...
Sorry, I was trying to make my comments short and simple and not get into too many what if scenarios so of course left a lot of gray areas.

I agree that 99.99% of the urgent or emergency situations a short time under power will work but I could sit here think of plenty of situations where extended power could be called for. Just one that comes to mind that I know has happened to plenty of cruisers. Thunderstorm pops up in the middle of the night. Your anchor starts dragging and you're headed towards the beach. It's dark and the exit from the harbor is not navigable without visibility, there are reefs around the harbor so finding a new spot to drop the hook could be dangerous, so you have to motor against the winds to hold position. If you're batteries are almost dead then you could be in trouble.

This is one scenario. I could sit here and play what if this and that but one could do that with anything boating. I could do it with diesels, with different rigs, you name it. The situations I'm thinking of are not common, don't happen often but they are possible, especially if you're cruising full time and are visiting a lot of out of the way places.

Electric I see as a practical option for two types of boaters. Those that day sail, weekend or coastal cruise, typically in a limited area, with the option to always choose the time, tide and weather and stay home if it is even slightly marginal. Or, serious cruisers with the boat, skills and experience to sail without power at all and use the electric strictly as a convenience to get in and out of harbors that are not accessible under sail.
I'm sure I could think of other categories but these two I think would cover the majority.

Just to be clear. I am not against electric. I would love to go electric. For several reasons it would offer me several benefits. One that would be huge to me is the elimination of my V-drive and the improvement in access to the stuffing box and bilge area. Would also dramatically simplify alignment for me. I'm just not willing to pay the premium or give up the range under power.
__________________
The water is always bluer on the other side of the ocean.
skipmac is online now   Reply With Quote
Old 21-08-2015, 08:58   #35
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: 12,374
Re: Electric Inboard

Quote:
Originally Posted by micah719 View Post
Full throttle from cold is not good for the engine. The electric system is much simpler and has less to go wrong. Murphy likes to stow away for those exciting moments. The people who are happy with electric are those who have made it work for their needs; as I said, it isn't for everyone.

Nobody is born with the knowledge and skills to make it work, they all have to learn. I'd suggest anyone simply seeking plug'n'play solutions is in for an expensive and frustrating ride, especially as a "cruiser", whatever that is. This is one place to start learning, though it is difficult with folks that seem to specialise in trying to shoot other's dreams and hopes down in flames without addressing the reasons why someone may prefer doing something different, or helping them.

Look around CF at the things that folks consider the negative experiences of cruising, and how many of these things relate to engines and electrics. The real problem is, we're using a patchwork of solutions that others developed under pressure from markets and cultures; the thread holding the quilt together is money, and sleeping under it is stressful. From what I've learned from the electric boat people, they're happy and their solutions work for their needs and circumstances; that doesn't mean they're suggesting a blanket diktat for everyone else to do what they're doing.

With research and study an affordable and convenient electric solution is achievable, and the compromises in range and cost are acceptable given the other advantages gained.
I would agree that most people are happy with their conversion to electric but absolutely not all. I have read in this forum and elsewhere about a number of owners that have pulled out the electrics and gone back to diesel. This applies mostly to larger boats and long distance cruisers.

Regarding one comment you made in your post. "Look around CF at the things that folks consider the negative experiences of cruising, and how many of these things relate to engines and electrics. " Not clear but perhaps you were relating this to electric power as well. If not, don't forget that electric propulsion uses a fairly complex control system and a plenty of wiring that typically carries high voltage and high current. All of these are issues that require maintenance and can cause problems over time.

I think this is what you were saying but I agree that electric can be convenient. Affordable yes but not cheap or cheaper than ICE and only if one can make significant compromises with range and/or speed.

I don't see the majority of the members posting on this thread trying to shoot down anyone's dreams and hopes, just trying to present the potential downsides so those reading this thread will be able to make a fully informed decision.
__________________
The water is always bluer on the other side of the ocean.
skipmac is online now   Reply With Quote
Old 21-08-2015, 09:39   #36
Registered User
 
TacomaSailor's Avatar

Join Date: Nov 2012
Location: Burnt Store Marina, SW Florida
Boat: Caliber 40
Posts: 1,148
Re: Electric Inboard

"So, the big question is range. There were some funny range numbers posted here, but let me say this; If I can get my 4 knots at 20 amps, (fingers crossed),"

I think I found a fundamental error in your calculations. That boat (with two passengers and some water onboard) needs almost 5 HP (3.8 Kw) to move at 4 knots rather than the 1.2 HP (0.96 Kw) you are using for range calculations. Following is a well tested calculation.

Freedom 32
32' 9" LOA
25' 3" LWL
12' 3" Beam
8,500 pounds with no cruising load

Every calculation I do shows that boat would need 4.7 HP at the prop to move that boat at 4 knots. Both Bebe and Gerr formulas predict the same thing.

If you add 500 pounds of equipment and liveaboard stuff (real cruiser?) you then need 5.0 HP at the prop to move 4 knots.

Using the light load (no operator, no water, no clothes...etc) your batteries would need to deliver 3.5 Kw power or FOUR (4) times your estimate of 0.96 Kw (20 amps x 48V). Range is a linear function of power consumed so your range would drop by a factor of four (4).

How in the world did you calculate a 4 knot power demand of 1.3 HP for a 32', 4 Ton sailboat?

And, no power system is 100% efficient. Looking at a more realistic case with 96% efficient power system and 500 pounds load on the boat your batteries must deliver 3.9 Kw to move the boat at 4 knots in still water. Your calculated range of 50 NM drops to less than 12 NM.

What happens when you have a 5-knot head wind or a 1 knot adverse current.

It still does not make sense!

Here is an online power/speed calculator for sailboats:
Boat Speed Calculator
__________________
TacomaSailor is offline   Reply With Quote
Old 21-08-2015, 10:01   #37
Registered User

Join Date: Feb 2015
Posts: 413
Re: Electric Inboard

An electric catamaran would be fine. You would need the entire top covered in panels, and not have sails or rigging to block them. Oh, and a diesel backup.
__________________
sailnow2011 is offline   Reply With Quote
Old 21-08-2015, 10:32   #38
Registered User

Join Date: Apr 2013
Posts: 4,877
Re: Electric Inboard

Quote:
Originally Posted by micah719 View Post
Full throttle from cold is not good for the engine. The electric system is much simpler and has less to go wrong. Murphy likes to stow away for those exciting moments. The people who are happy with electric are those who have made it work for their needs; as I said, it isn't for everyone.You seem to be trying to twist the facts in electric drives favor but ignoring reality. If every time you started the motor, you immediately firewalled the throttle, I would agree that is hard on the engine but in rare emergency situations, the odds of it doing any measurable harm are negligible. Also while an electric motor may be fairly simplle, as you say murphy can bring a loose or corroded connection to your attention just as easily during those "exciting momments." Electronic controllers in a salt water environment are also likely to have issues. I've yet to see a statistically valid analysis showing these systems are less prone to failure (mostly because there are very few due to thier impracticality) but I have seen enough issues brought up to believe that current systems are no more reliable than a diesel drivertrain. If you go diesel-electric they are likely less reliable as you have all the failure mechanisms of a diesel plus the failure mechanisms of the electric systems.

Nobody is born with the knowledge and skills to make it work, they all have to learn. I'd suggest anyone simply seeking plug'n'play solutions is in for an expensive and frustrating ride, especially as a "cruiser", whatever that is. This is one place to start learning, though it is difficult with folks that seem to specialise in trying to shoot other's dreams and hopes down in flames without addressing the reasons why someone may prefer doing something different, or helping them. Big difference between someone who knows electical systems and electronics cobbling something together and someone with little or no knowledge trying to troubleshoot an off the shelf system. At least with a diesel system, another cruiser in the anchorage is likely to have some diesel troubleshooting skills or worst case hire the local diesel mechanic. A one off electric drivetrain and you are likely on your own. Until that changes (and it's unlikely to) there won't be a market for electric drivetrains on cruising boats.

Look around CF at the things that folks consider the negative experiences of cruising, and how many of these things relate to engines and electrics. The real problem is, we're using a patchwork of solutions that others developed under pressure from markets and cultures; the thread holding the quilt together is money, and sleeping under it is stressful. From what I've learned from the electric boat people, they're happy and their solutions work for their needs and circumstances; that doesn't mean they're suggesting a blanket diktat for everyone else to do what they're doing. Most people are quite happy with their diesel engines. As mentioned the people who commit to an electric drivetrain, generally know they are taking an extreme position and have a tendency to paint it with a happy brush rather than admit the major downsides.

With research and study an affordable and convenient electric solution is achievable, and the compromises in range and cost are acceptable given the other advantages gained. Only if you are trying to prove a point not to produce a viable drivetrain. The downsides are many and major. This isn't a new subject where we just need to work the bugs out. It's fundamentally limited by physics. Until someone comes up with a battery system that can compete with diesel for energy storage it won't change.
Someday it might change. If gas/diesel goes up to $20/gal, we may decide it's worth the reduced performance or if you get a battery that is pound for pound comparable to a gal of diesel, you will see a sudden and quick shift to electric drivetrains. Neither of those appears to be coming.
__________________
valhalla360 is offline   Reply With Quote
Old 21-08-2015, 10:50   #39
Marine Service Provider

Join Date: May 2012
Location: New Orleans
Boat: We have a problem... A serious addiction issue.
Posts: 3,940
Re: Electric Inboard

Quote:
Originally Posted by valhalla360 View Post
Someday it might change. If gas/diesel goes up to $20/gal, we may decide it's worth the reduced performance or if you get a battery that is pound for pound comparable to a gal of diesel, you will see a sudden and quick shift to electric drivetrains. Neither of those appears to be coming.
I would switch tomorrow if I could swap out a diesel tank for batteries that were just twice the size as my fuel tank. But so far as I know there isn't anything even close. Standard FLA store about 2% by weight of diesel fuel, and about the same by volume. LIFEPO is something like 2.5% by weight and 3% by volume. We aren't talking moderate improvements, there needs to be a massive disruption in the technology. I don't even know if it is chemically possible to improve batteries enough.

The really breakthrough may require something like carbon nanotube flywheels or something equally exotic to get close to the energy density of diesel fuels.
__________________
Greg

- If animals weren't meant to be eaten then they wouldn't be made of food.
Stumble is offline   Reply With Quote
Old 21-08-2015, 10:51   #40
Registered User

Join Date: Apr 2013
Posts: 4,877
Re: Electric Inboard

Quote:
Originally Posted by sailnow2011 View Post
An electric catamaran would be fine. You would need the entire top covered in panels, and not have sails or rigging to block them. Oh, and a diesel backup.
I recall seeing something like that online. It's actually a neat idea and worked (but still with some limitations, speed was still limited and they used super narrow hulls to keep power needs down which limited carrying capaicty). It was pretty pricey compared to a typical sail catamaran.

I believe they still needed more than 20amps to achieve 3-4kts.
__________________
valhalla360 is offline   Reply With Quote
Old 21-08-2015, 10:51   #41
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: 12,374
Re: Electric Inboard

Although not directly related to the practicality or affordability of an electric drive, one thing that I don't understand and find quite annoying is the cost of production, "marine" drives.

All of the companies making systems for boats charge a fortune for the motors. I have seen heavy duty, 30-40 kW industrial motors for under $2000 but I see 10-12 kW motors for "marine" systems for double, triple and higher prices.

I can buy a brand new drive motor for my Prius, about 60 Hp for under $1000.

I doubt seriously that many if any of the "marine" suppliers are building their own motors specifically for their electric drive system. In all likelihood they are buying something off the shelf and adding a mounting system, wiring harness and controller.

If marine, ready to install systems were more realistically priced I think there would be a lot more people buying them.
__________________
The water is always bluer on the other side of the ocean.
skipmac is online now   Reply With Quote
Old 21-08-2015, 10:54   #42
Registered User
 
Terra Nova's Avatar

Join Date: Apr 2007
Location: Marina del Rey, California
Boat: Freya 39 cutter- Terra Nova
Posts: 3,645
Re: Electric Inboard

Quote:
Originally Posted by StephieDee View Post
...We're really interested in an electric motor verses the diesel...
A ridiculous waste of money. And bad boat karma, destroying an otherwise good boat.
__________________
1st rule of yachting: When a collision is unavoidable, aim for something cheap.
"whatever spare parts you bring, you'll never need"--goboatingnow
"Id rather drown than have computers take over my life."--d design
Terra Nova is offline   Reply With Quote
Old 21-08-2015, 11:05   #43
Registered User
 
TacomaSailor's Avatar

Join Date: Nov 2012
Location: Burnt Store Marina, SW Florida
Boat: Caliber 40
Posts: 1,148
Re: Electric Inboard

Can we determine the power needed to move a Freedom 32 through still water?

The Yanmar Prop curve for the 3GM20 shows the following power at the prop for a given RPM:

2.0 HP 1800 RPM
2.9 HP 2000 RPM
3.0 HP 2100 RPM
3.3 HP 2200 RPM
3.9 HP 2300 RPM
4.5 HP 2400 RPM
4.9 HP 2500 RPM
6.0 HP 2600 RPM

What speed did the boat move at various RPMs - then we can determine the power the batteries need to supply for a given boat speed.

We can then use simple arithmetic to validate the various power and range claims being thrown around in this discussion.

Numbers - the truth!
__________________
TacomaSailor is offline   Reply With Quote
Old 21-08-2015, 14:03   #44
Registered User
 
Wireless1's Avatar

Join Date: Jan 2012
Location: Southern California, USA
Boat: Beneteau 473
Posts: 145
Re: Electric Inboard

Quote:
Originally Posted by valhalla360 View Post
If you are willing to accept 3.5kt crusing speed, you need to drop the diesel down to maybe 3-5hp and take into account the improved efficency to do a comparison. Now you might be talking about 45miles on a couple gallons fuel. A fairly typical 100 gal tank would provide ocean crossing capability.

Of course, if you get into a storm and your sails blow out, your system will be SOL trying to hold you in place. Or if you take it up to a half way reasonable cruising speed and your range drops back the 5-10miles we've been talking about.

For a die hard doing it just to prove they can use electric, 3.5kt cruising speed is fine. For a cruiser looking for the best all around propulsion system it's not viable and that's why retail systems haven't taken off.
Well, I agree, and nobody said you didn't have to have great seamanship and plan ahead for all one might encounter. Some of us with NO motors are capable of safely cruising oceans, and some with the latest greatest gadgets and great engines are not. I probably fall somewhere in the middle. Regarding me perhaps as being a diehard trying to prove anything; there may be those, but for me and my sailing requirements, I'm fine with electric propulsion. I mostly sail out to the Channel Islands off So.California. For me electric gets me out of the harbor and then I sail. However, my LiFePO4 batteries have the range to get me to the island should the winds die. I usually hang out there a week or so then return home. During a sunny week my batteries will be nearly, if not fully charged as the boat just sits in the sun. So, I'll be nearly all charged up for the trip home. And if I'm not? I can handle that as well. I will never take the motor system batteries down to flat and they will always have a 20% reserve run time. Thus I will sail to the harbor mouth and then be able to motor the short distance back to the slip. BTW, my system has a time to go feature that no matter what speed I need to run at the readout shows me how many hours and minutes I have left in the batteries at that speed. It's constantly changing depending on the speed you set it at, so that makes it an easy Speed/time/distance nav calculation. BTW, the EV cars guys brutalize their LFP batteries and actually do take them down to zero on rare occasions. That's pretty bad on the battery chemistry. However, they charge them right back up again and off they go. If you don't over charge LFP's it's amazing the punishment they can take---but don't even get close to an overcharge situation. That is a huge no no and will cost you the price of a new pack. YMMV...
__________________
s/v "Bamboleo" - Freedom 32 (Hoyt)
Farrier Trimaran -- Morgan 41 Classic,
Rawson 30
Wireless1 is offline   Reply With Quote
Old 21-08-2015, 15:08   #45
Registered User
 
micah719's Avatar

Join Date: Jul 2012
Location: Somewhere in Germany
Boat: OEM, proportional
Posts: 1,436
Re: Electric Inboard

Thanks Skipmac, your posts are well-thought and -written, honest and helpful. I like talking with you because your arguments directly address mine and force me to self-critisise; this is good because it tests assumptions and conclusions by fire. I'd rather learn this way than paying for it in meatspace by losing my boat, or sitting in said boat weeping over an expensive pile of copper, lead and failure. It is more pleasure and privilege to help others get where they want to go, in their way, than it is to be helped in one's own. It is also humbling and necessary to have one's countenance sharpened by a friend, lest circumstance bash it in.

Hypothetical situations can be most useful for thought experiments, since we aren't prophets and we have to plan ahead to try and cover the worst. We have the benefit of hindsight upon one's own and other's real-world experiences to draw from. After reviewing many accounts of the various calamities that befall cruisers, I've noticed that most occur because of poor prior planning leading to a succession of failures which individually are quite managable, but taken together multiply into an unstoppable cascade. The dogmas of our time are a patchwork of solutions invented by other people; sometimes their problems are the same as ours and sometimes the only tools we have are the same as theirs; but this doesn't free us from looking honestly at the situation and asking difficult questions. Heaver-than-air flight and hand-washing are two things that were once hotly denied as useful, advisable or achievable things; yet today anyone arguing the contrary would meet almost as much resistance as the pioneers of those ideas met when they were heresy.

The hypothetical you suggest above assumes that a cruiser was in a tight anchorage, in poor weather conditions at night, and had an anchoring failure. Focussing on the subject at hand: engine; and assuming all the other variables were already addressed. Eg: noelex 77 did your anchoring, you listened to Anchorage Guy (or his equivalent for wherever you are), and whoever the CF weather- and seamanship- gurus are also taught you their best. Focussing on our last resort: Engine; discounting yuloh's, sweeps, tows from other boats, teleport systems, etc. Throwing in flat batteries in a battery-only system requires either incompetence on the part of the cruiser, or a technical fault outside his control. However, direct-drive diesel engine systems can also have technical faults of the same kind that disable electric systems, only they have even more points of failure. You've stated the range limitation of batteries which require excessive weight and cost to overcome.

Your classification of cruisers into two categories is very useful. The daysailer can get away with a battery based system, but he shouldn't think of his setup as anything more than a docking assist. The cautious cruising sailor can also get away with this approach as long as he stays within its capabilities. This kind would already be very cautious in anchoring, knowing he hasn't the luxury of motoring about in dead of night for a second chance at staying off the beach, or that multi-million dollar yacht with the slavering lawyers baying at the rail. Not a bad way to sail even for those with standard propulsion! Gamble long enough or for high enough stakes and one loses; I was a croupier long enough to relish gutting the stupid punter, and there were many. Getting caught in a failure cascade is preventable; push the probability toward impossible, and build in fail-safe outlets rather than fail-deadly. It will cost: in money, time, convenience, prestige, or life itself. I'm poor, have no deathwish, care nothing for prestige and can stand discomfort and inconvenience when necessary, so I'm freed of those limitations. Time, I am spending now, to save it later. Lack of imagination and intelligence is a hindrance but at least I'm using my preparation time. It isn't natural and also goes against conditioning in this perverse consumer culture I was blessed to be born into; and with much gratitude to hard task-masters past and present, I might make it yet.

The long range electric cruiser would be wise to include a diesel engine in his power sources: stored energy density of diesel fuel is unmatched. Endurance independent of sunshine, shore power, and current (and near-future) battery technology. Scheduling inventions never works, we have to go with what we have and what is already almost here, not pipe-dreams. As a side benefit, an electric system can more easily accomodate other electrical loads which for the standard direct-drive system are alien addons; but which we moderns increasingly see as essential to the success of our ventures (they aren't). The core of a direct diesel system is the prop-shaft and what hangs off it, and unless there is an additional genset the direct propulsion which is trying to be optimal for driving the prop also has to handle the electric generation needs; to the detriment of both.

Think of an electric motor on the prop shaft as simply a different kind of transmission. Much is made of energy losses in conversion. Diesel engines have certain rev-ranges where they are happiest and most efficient, and experience the least wear. How often does a cruising sailboat actually use this optimum rev-range? What proportion of wear and cost occurs outside the optimum use? The propellor is vitally important in this: folding props are by nature compromised in efficiency since they must achieve minimum drag during the most common use of the boat. Fixed blade props are better for motoring but force a drag compromise for sailing. The nature of the hull and its surface condition, design and actual displacement, wind and wave resistance, counter currents....many factors which mean typical installations are restricted to very specific conditions to achieve their optimum efficiency. Yet this is the efficiency which crops up in arguments against electric, as though it were the sole deciding factor. It is indeed important, but are we being honest about how and when and if it is achieved?

I've looked at propellor choice; based on info supplied by cruisers here at CF and reinforced by my researching the web, the easiest and best choice for my small yet heavy boat is a Variprop(tm). Pitch can be adjusted without hauling the boat, and it can achieve the low-drag of a folder. I may yet change my mind, but right now it's the cat's meow. I'm insisting on bilge keels so I can "haul" my boat any time I find a suitable tide and place, and I haven't come to the money-on-the-table moment yet, so Maxprop(tm) may still have a chance. Ok, I'm preparing for a new build in steel, but for a time I was contemplating purchasing a used GRP boat and using the very same d-e system, no changes at all. Essentially it is a complete re-power, but boats of that age usually need it anyway. Components of the old system could easily be re-purposed into the new, so it isn't necessarily starting from scratch. I pay in time, thought and sweat what others pull out of their wallets, initial and on-going. Pain now, pleasure later, the ultimate laziness!

Yes, I realise an electric system will have its own complications. It will require maintenance and incur costs, it has its own failure points and modes. Ideally, I would leave the diesel attached to the shaft in some way to provide even more redundancy. However, I'll take the risk of totally de-coupling it so that I can better use that space, taking into account many other things to balance. Remember, I'm still 50/50 on having the engine at all! I could get away with a little gas-powered genset for a stick welder (my little fix-anywhere steel battleship), and a small solar panel to charge a radio/nav battery if I want to go simpler. I'm spending my time now to research how to do it best and cheapest; I do not expect to get away free, indeed I am willing to pay a little more in initial outlay for benefits later, in significantly less lifetime costs in addition to the various other benefits. I believe I can achieve much the same range or better, with more reliability and versatility and real-life convenience. It may cost a little more in initial cash outlay and certainly much more in research and planning; but at the sharp end when I have to rely on what I have with me on my boat it will be more self-reliant and robust. I can't rely that there will be spare parts and service where I'm going, let alone rescue. Better to avoid those stark choices in advance, even if it means discomfort. We are far too coddled as it is, and a reckoning is coming down the pike. The later it comes, the harder the terms.

There are success stories in electric, and failures; the same can be said of the status-quo in direct-drive diesel. I believe the failures are not because of inherent deficits in those systems but in the applications; and honestly talking about the facts of both and acknowledging the weaknesses of both approaches can only benefit both sides; more acceptance of electric will iron out best and cheapest practise; and also help diesel-centric systems, though there are many interests that would rather just leave thing$ a$ th€y ar€.

Lastly; thankfully there are few that concentrate on merely opposing something without supplying an alternative, or even grounding their argument on sound foundation. I count this as part of the deal when one tries to buck trends, it is to be expected but one can also tune it out. It is not helpful and the trap lies in trying to oppose it. Better to simply tune it out, better for both parties and all spectators; there is a difference between stubborn tall-poppy shooting and honest discourse. Thanks again for the latter, and for reading this far. I don't mean to condemn existing systems, just to point out my thinking as I adapt them to better fit my needs. If you're served by this, then I'm glad to have passed on what I gained from others. If I'm wrong, I hope and try to be honest and humble enough to listen to reason. This doesn't mean I'm going to cave in the face of pressure for the sake of it; if any feel such from me, then be assured it is not intentional. Do what you think is best for you; we'll both have to live with our choices.
__________________

__________________
Ps 139:9-10 If I take the wings of the morning, and dwell in the uttermost parts of the sea; Even there shall thy hand lead me, and thy right hand shall hold me.
micah719 is offline   Reply With Quote
Reply

Tags
electric

Thread Tools
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
For Sale: Sailboat inboard electric motor system for sale lazystar@aol.com Classifieds Archive 9 12-03-2015 10:01
For Sale: PAR Electric System Water Pump and JABSCO Electric Bilge Pump hanks Classifieds Archive 3 05-03-2014 20:03
For Sale: Electric Motors and hydraulic electric lifter arms 4 sale Sea Shoes Classifieds Archive 0 25-03-2012 08:46
Replacing Inboard Engine with Electric Motor boat_alexandra Engines and Propulsion Systems 10 30-12-2009 21:50
Electric consumption of Inboard autopilots. Tonick Monohull Sailboats 7 10-01-2009 05:21



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 19:57.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.