Longest time/distance you've had to motor?

[deckofficer]

Originally Posted by Aargau

I feel like solar/battery/brushless electric propulsion will be the wave of the future once battery energy density gets within 15% of diesel, but right now it's not.

However, the longest I've had to motor was 2 days, and that wasn't strictly necessary, light winds between Tonga and Fiji. It was a pretty slow but sturdy monohull, and we had a flight schedule. Same boat had to motor 4 days between Galapagos and Marquesas, but that was also due to some urgency with supplies and repairs.

So I'm interested in real life examples of necessary long motors, such that if an electric/battery motor can't meet that range, it's not ready. I would be doing another trans-pac and possible round the world trip, so anywhere that requires sustained motoring is interesting.

I agree on the solar/electric propulsion.

I used to motor between Tacoma, Washington and Thailand with stops in Japan. My fuel burn at 20 kt was around 130 tons per day.

[rebel heart]

~300 miles, three days. Sea of Cortez.

[mbianka]

Originally Posted by 44'cruisingcat

A Honda 2000 produces 2kW. That's about 3 horsepower. A decent sized cruising boat won't manage much motoring speed from that. But use any more power than that, for any length of time, and your batteries will go flat.

You need a generator which at least matches your motor's power output if you're going to motor for any distance.

Ssssh! Don't say that too loud or my generator and EP system might hear you. Yes, a Honda 2000 hybrid system like mine may not work on larger boats as well. But, the nice thing about EP systems is you can scale and change things as needed. Plus I also use the generator for multiple tasks on board. Just like I use the EP system in ways that I never would operate if I still had a just a diesel on board. Plus the EP system is much more efficient at turning the prop and does not need to be the same HP as the diesel it replaces.

[seandepagnier]

1hp electric drive is equal to typical 4hp diesel because it is far more efficient, and the propeller is far more efficient. Traveling at 80% of the typical 1.34*sqrt(lwl) hull speed is far more efficient than right at hull speed. So 1hp is enough to drive a 30ft boat at a reasonable speed (4 knots), and also you can obtain this amount of power from solar panels on the deck of this size boat. On larger boats you will travel slightly faster, smaller boats slower, when scaling up or down (same as sail power)

Using a generator to power an electric motor is almost as bad as using a diesel engine. Sort of like putting a fat person in a wheelchair.. it's actually bad for everyone. To fix the real problem you must lower consumption.

I use solar panels to power electric motors, and I have no problem motoring in calms with no battery drain. I can motor for up to 12 hours on my bank of 8 golf cart batteries because sometimes it is overcast, or night time.

If there is wind (3 knots or more) you should be sailing not motoring. Unfortunately for the future of the world, most people are very selfish consuming resources to run an engine when there is wind to sail: failure.

[mbianka]

Originally Posted by ArtM

Anyone know why the hybrid engine on the Lagoons was such a disaster? I love the hybrid systems on Toyota, and it seemed like Lagoon had created a similar system..


Would love to have a boat with hybrid propulsion. MBianka, I'd really like to know more about your experience with this - how you're using it, range, fequency to run the generator, etc.

If the Lagoon 420 hybrid could be "fixed" of whatever problem it had, I'd put it high up on my 'to buy" list.

Art:

Not sure what Lagoon's problem was though I suspect complexity had something to do with it. I seem to recall they had a rather complex generator monitoring automatic charging system that was not quite debugged before they sold some of the boats. They might have also tried early Lithium battery technologies without fully understanding them. I just don't recall their issue. There is a fellow Steve who I believe sails an electric Lagoon with a revamped system in the Chesapeake and is very happy with it.

As for my experience with my poor man's hybrid setup. I start out with the premise that I own a sailboat. So I sail. If the wind dies I will crank up some electric propulsion and do it a lot sooner than when I had a diesel. It's quiet and keeps you moving. When the wind really dies I can operate in hybrid mode until I run out of gas or until the wind picks up. Whichever comes first. Plus when I do motor it is very quiet and much less vibration than having the diesel chugging away under your feet. Here is how I make the decision to operate in hybrid mode. When my battery bank has dropped to 70% of capacity that's when I think about firing up the generator. This might be an hour or two after turning on the EP. But, usually the winds have piped up well before I ever get to that point. Though I have motored for up to ten hours and stopped only because I reached my destination.
But, I also use the EP system to my advantage and keep finding more uses for it all the time. For example when the winds are light I'll crank up the EP to a 10 amp current draw. That gives me about 2 knots boat speed alone. But, what this also does is negate any prop drag so there is no need for me to ever think about buying a folding prop which would not be good for regen (charging the battery when under sail) anyway. When the wind really dies I can operate in hybrid mode until I run out of gas or until the wind picks up. Whichever comes first. Plus when I do motor it is very quiet and much less vibration than having the diesel under your feet. No noise fatigue. I like that too! When I anchor I just run the generator just long enough to top up the batteries (or if at a dock plug in). Then let solar panels and wind generator keep things topped up until it's time to sail again. Though I do sometimes tap into the EP battery bank for energy like running the laptop to make sure I don't drain the house bank too much on overcast days when it's solar panels may not be able to keep up with the house demands. Nothing wrong with having a 10 KW battery bank as a backup on board.

[HappyMdRSailor]

Outer Banks, NC to Marina del Rey, CA....

Southern route... As recommended by Rand McCornell....

Texas is B%$#C of a passage....

[zumsel]

600 miles in 9 days when I got dismasted in 2011 on my way across the Atlantic from Horta to Halifax, Nova Scotia.

Had to ask a Tanker on his way to England for some additional diesel.

[44'cruisingcat]

Originally Posted by boat_alexandra

1hp electric drive is equal to typical 4hp diesel because it is far more efficient,

Not from what I've seen. There were two boats the same design as mine, fitted with 5 kW electric motors, which were claimed to be equivalent to 10hp outboards. In reality they weren't. They were what they were - 7.5 hp motors.

And to run them continuously required a 10kW genset.

[bene505]

Originally Posted by Aargau

I feel like solar/battery/brushless electric propulsion will be the wave of the future once battery energy density gets within 15% of diesel, but right now it's not.

However, the longest I've had to motor was 2 days, and that wasn't strictly necessary, light winds between Tonga and Fiji. It was a pretty slow but sturdy monohull, and we had a flight schedule. Same boat had to motor 4 days between Galapagos and Marquesas, but that was also due to some urgency with supplies and repairs.

So I'm interested in real life examples of necessary long motors, such that if an electric/battery motor can't meet that range, it's not ready. I would be doing another trans-pac and possible round the world trip, so anywhere that requires sustained motoring is interesting.

IMHO...

You can quickly get a better answer that factors-in experienced people's risk tolerance, by asking 1) how many gallons of diesel they bring with them on passages, and 2) how many (sunny) days long those passages are typically reported to be. Then you can better match your battery bank and solar panel sizing to match their very real motoring limit, and still account for enroute solar charging.

(Factoring-in regenerative charging from the prop would need some additional questions, or at least changing the first question to 3) how many gallons of diesel they had with them at the beginning of their longest duration of motoring.)

---

Part of this comes down to energy storage, helped by your in-passage charging. But the other part may be best served by asking what peak horsepower they have ever really needed, with "need" well defined.

(With a 4 cylinder diesel on a 50' boat, we can motor into 50 knot winds with ease. We've done just that, but it was on a delivery when we really didn't need to. So that one doesn't count.)

Regards,
Brad

[nimblemotors]

I have mostly decided to not have any sails and build my boat using a hybrid drive of both gasoline and electric propulsion. There is no question that you can't beat liquid fuel for energy density. There is also no question you can't generate such fuel yourself and must go ashore to buy more of it when you run out. Solar doesn't run out, and what makes it so attractive is that sitting at anchor it continues to provide great value.
With the current collapse in the price of panels, it makes more sense than ever.

What is really needed for a yacht is a way to store a lot of generated electricity.
If you could store enough energy to travel long distances, you can generate it while at anchor until you have enough to make a passage.
Unlike for cars, a yacht system could be big and bulky and inefficient, but must be cheap and have high energy density
Current batteries are not even close. What is needed is something more like creating liquid fuel from electricity on board. I don't know of any way that is possible at present, but that is the kind of breakthrough needed.

A significant improvement would be using zinc-air batteries.
They have 4x energy density than lithium. If one can recycle zinc-oxide back into zinc using a system small enough to fit on board, it would be a big improvement.
Zinc

JackB

[harmonytek]

Originally Posted by ArtM
Anyone know why the hybrid engine on the Lagoons was such a disaster? I love the hybrid systems on Toyota, and it seemed like Lagoon had created a similar system..

Automotive loads are usually low, with peak power required for short durations, and regenerative charging from braking. Boat loads are constant so the power train is...
deisel to electric to propeller, which is less efficient than deisel to propeller. The only benefit is solar recharging at an optimistic 2 hp*hr/hr for 8 hours per day, which means you could motor at 32 hp for an hour every other day.

[boatman61]

Agua Dulce, Med Spain to St Katherine's Docks, London... 30ft steel sailboat over rigged and unsailable.. motor sailed with the main all the way..

[nimblemotors]

I am very familiar with the Prius, having owned many of them and torn them apart and put them back together. The hybrid uses electric power for acceleration, but a major MPG improvement in a Prius is because of the eCVT. It allows the gasoline engine to be tuned to produce higher efficiency at a narrower rpm than a normal car engine.
So in fact, a prius like drivetrain would work in a boat. Run the engine at peak efficiency no matter what speed/load, and use the electrical "transmission" to propel the boat and charge the batteries/power equipment on board.

Of course, this is more complicated, and at a brand new OEM system level, very expensive. But that is not my world, my world is plethora of cheap used equipment.

JackB

[deckofficer]

JackB,

You and I speak the same language. I have 3 EVs, an electric kayak with LiFePO4 cells for a 80 nm range, and have followed all the electric offerings.

10 KW of solar, crossed the Atlantic at 5.5 kt.
transatlantic21: The world's first crossing of the Atlantic on a solar boat

8 KW of solar, 6000 nm cruising Europe
Boat - SolarWave

6 KW of solar, can manage 3.9 kt for 24 hours on 5.5 hours of sun.
Island Pilot DSe Home Page

[44'cruisingcat]

Originally Posted by nimblemotors

I am very familiar with the Prius, having owned many of them and torn them apart and put them back together. The hybrid uses electric power for acceleration, but a major MPG improvement in a Prius is because of the eCVT. It allows the gasoline engine to be tuned to produce higher efficiency at a narrower rpm than a normal car engine.
So in fact, a prius like drivetrain would work in a boat. Run the engine at peak efficiency no matter what speed/load, and use the electrical "transmission" to propel the boat and charge the batteries/power equipment on board.

Of course, this is more complicated, and at a brand new OEM system level, very expensive. But that is not my world, my world is plethora of cheap used equipment.

JackB

You can run a motor in a boat at it's optimum RPM, without going through the diesel-genset-electric motor route. It's just a matter of getting the propellor right.

Hybrids work on cars because cars have to operate at a huge variety of speeds. They also typicaly spend large amounts of time idling and going nowhere. Boats generally run at constant speed, and rarely get caught in traffic jams.