Oceanvolt Hybrid Motor

[Jim Cate]

The infrastructure for shore power recharging is either available at regular intervals/distances, or at least it could easily be made so. If some cruiser chooses not to use it, it his/her own problem if batteries of their boat run out of energy.

Yes, if a canal boater goes to a dock or marina, there may be a shore power connection available. But not everyone wants to go to such places every day or two, and they are the ones that make me add the "SOME" qualification to Valhalla's generalization.

When Ann and I joined our friends in the Alsace region we were aboard for two weeks. During that time we spent two nights tied to a wharf, and one of those was in order to get us off to a train. The rest of the time we just tied up to a bank wherever we ended up in the evening. No shore power then, likely not now, unlikely in the future... it was in the woop-woop (at least by European standards).

I agree that one could design a canal boat specifically for solar electric and make it work most of the time. But to say it can be done with little or no impact... well, having to give up one's beloved canal barge in order to move onto a light weight, narrow low drag boat festooned with solar panels and stuffed with Li cells... that qualifies as impact in my book.

But enough quibbling. Times and infrastructure are changing, and electric driven boats of many sorts loom in the future. I doubt if many electric Peniche's will be seen.

Jim

[valhalla360]

Originally Posted by Jim Cate

Would you accept that edit? You have not explained how non-marina or dock oriented canal boaters would recharge routinely.

Jim

No, I wouldn't accept that change. While technically not incorrect, it is implying something inconsistent with my point. A large percentage of canal cruisers could use EV without significant impact to how they cruise. This is unlike the sail boat scenarios where we are asked to suspend belief and assume people will accept drastically different performance under power. This is a scenario where cruisers could use their boats in largely the same manner they are accustomed to using them.

I did explain how solar would be viable in post 1182.

Pure EV off only solar is doable but has some limits on a narrow-boat (the worst case scenario I mentioned) but they tend to travel even slower (using less power) and are on small canals with lots of locks (where they use negligible power for a significant portion of the cruising day). A wider beam boat and pure solar works fairly easily as there is room for the panels.

[valhalla360]

Originally Posted by Jim Cate

I agree that one could design a canal boat specifically for solar electric and make it work most of the time. But to say it can be done with little or no impact... well, having to give up one's beloved canal barge in order to move onto a light weight, narrow low drag boat festooned with solar panels and stuffed with Li cells... that qualifies as impact in my book.

But enough quibbling. Times and infrastructure are changing, and electric driven boats of many sorts loom in the future. I doubt if many electric Peniche's will be seen.

Jim

It sounds very similar to the blue water full keel sailboat argument. Almost no one is building or buying them but the old codgers try to justify their choice by talking about the beauty and love rather than functionality.

They do make new Peniches but most of the new ones are actually fiberglass facsimiles, similar to some of the "trawlers" that are modern hulls made to have the looks but really with little relationship to the original trawler design. The bulk of the new canal boats (non-Peniches) are modern fiberglass boats with little in common with the old bulk cargo hulls.

Of course, if all change is unacceptable, then you are right. Obviously, it's impossible to provide the exact same design because some people have an irrational love of their diesel engine and to remove that would be change and therefore unacceptable.

PS: I think you are overstating the Peniche portion of the European canal boat market. We loved the Erie and want to run the french canal system at some point, so when we get near it, we often go down to check it out. Discounting the boats in charter, I would say upwards of 75% of the boats on the canal system are not the old Peniches but newer modern boats that would be easily adapted. (the UK narrow boats are a different category)

[valhalla360]

Originally Posted by Just Another Sa

No, significantly below hull speed, when wavemaking drag is much smaller than viscous drag, water resistance of a given hull at a given speed is approximately proportional to wetted area.

How wetted area depends on weight with a given hull depends on shape, but it's never a linear relationship. The shallower the hull is compared to it's beam at waterline, the less any extra weight increases wetted area percentage wise.
If one wants to compare with absolute values instead, like how many more sqm for each extra kg of mass, then it's the water plane area and its perimeter length which counts. The more water plane area, the less is the increase of immersion per additional unit weight. And extra wetted area is extra immersion times perimeter length. For a very narrow canal boat, the perimeter length is almost a constant, and thus rate of increase of wetted area for a given extra displacement becomes close to inversely proportional to beam at waterline.

Thank you, I was on my tablet before and couldn't find the correlation readily.

Yes, more displacement increases wetted area but for a similar hull of the same length, it is far from a direct correlation between displacement and HP required.

[Just Another Sa]

Originally Posted by Jim Cate

Yes, if a canal boater goes to a dock or marina, there may be a shore power connection available. But not everyone wants to go to such places every day or two, and they are the ones that make me add the "SOME" qualification to Valhalla's generalization.

When Ann and I joined our friends in the Alsace region we were aboard for two weeks. During that time we spent two nights tied to a wharf, and one of those was in order to get us off to a train. The rest of the time we just tied up to a bank wherever we ended up in the evening. No shore power then, likely not now, unlikely in the future... it was in the woop-woop (at least by European standards).

I agree that one could design a canal boat specifically for solar electric and make it work most of the time. But to say it can be done with little or no impact... well, having to give up one's beloved canal barge in order to move onto a light weight, narrow low drag boat festooned with solar panels and stuffed with Li cells... that qualifies as impact in my book.

But enough quibbling. Times and infrastructure are changing, and electric driven boats of many sorts loom in the future. I doubt if many electric Peniche's will be seen.

Jim

It is not absolutely necessary to take your electric boat to a place where charging with shore power is available, just the batteries and a charger. You could use the very same public places as fully electric cars use, and take a taxi or use your electric assisted tricycle as transport vehicle for the battery + charger. If you don't fully recharge but just to something like 80%, it should't take forever to charge them while you can go to the supermarket or somewhere else necessary. A bicycle is not enough to handle all the load, and pedaling alone might not be convenient for the heavy load either if there are uphills to climb, thus 3 wheels and electric assistance. Not saying that all is a smart way to do things, but it's another choice for those not wanting to use marinas or other available infrastructure intended for boats.

[44'cruisingcat]

Sounds like an amazing idea. Disconnect a dozen or more cells, carry a hundred or more kilograms of batteries to your tricycle, then ride maybe 50 + km to a recharging station, leave the whole lot there while you go shopping, hope that nobody decides to help themselves to your $10,000+ worth of batteries, then return (hopefully) to your tricycle, then try to load the shopping on top of all those batteries....

Sounds like a fun way to get into hospital.

[valhalla360]

Originally Posted by 44'cruisingcat

Sounds like an amazing idea. Disconnect a dozen or more cells, carry a hundred or more kilograms of batteries to your tricycle, then ride maybe 50 + km to a recharging station, leave the whole lot there while you go shopping, hope that nobody decides to help themselves to your $10,000+ worth of batteries, then return (hopefully) to your tricycle, then try to load the shopping on top of all those batteries....

Sounds like a fun way to get into hospital.

Realistically, solar is the more viable option to recharge on a canal boat if you are dead set against ever going into a dock (though I suspect most do go in at least once or twice a week on average). Maybe add a small generator to top up if you are doing longer runs multiple days in a row. A generator running at peak efficiency to top up the battery bank but only generating 10-20% of the propulsion energy needed, will still result in a drastic reduction in diesel used.

The tricycle is probably not viable but a lot of the Peniches have a car on the stern with a crane. On a smaller one, you could probably do something like a electric golf cart (street legal version). Assuming you switch to lithium batteries and upped the storage capacity, you might be able to store 30kwh. You might simply have a smaller house bank and when plugged into the boat, the golf cart acts as part of a larger bank (no need to transfer electricity to the boats battery bank).

Probably doesn't make sense to do it purely for energy transport but if you get one for transport first, it could be a nice feature to supplement if you find yourself away from shore power and the sun isn't shining. Or vice versa if you aren't moving a lot, the solar can probably keep the golf cart topped up, so you never need to go to a charging station.

Once you have a viable electric propulsion use case, lots of side benefits open up. The difference here is canal cruising, the numbers work for normal propulsion assumptions, so we can move on and consider some of these side benefits.

[Stumble]

I got it. How about we use electric propulsion and a bunch of batteries, then add back a 10kw generator to power the thing. With as many solar panels as possible. For just $40,000 you can only use electric propulsion.

[Paul Elliott]

Originally Posted by Just Another Sa

No, significantly below hull speed, when wavemaking drag is much smaller than viscous drag, water resistance of a given hull at a given speed is approximately proportional to wetted area.

How wetted area depends on weight with a given hull depends on shape, but it's never a linear relationship. The shallower the hull is compared to it's beam at waterline, the less any extra weight increases wetted area percentage wise.
If one wants to compare with absolute values instead, like how many more sqm for each extra kg of mass, then it's the water plane area and its perimeter length which counts. The more water plane area, the less is the increase of immersion per additional unit weight. And extra wetted area is extra immersion times perimeter length. For a very narrow canal boat, the perimeter length is almost a constant, and thus rate of increase of wetted area for a given extra displacement becomes close to inversely proportional to beam at waterline.

Yes, you are correct. I was thinking more of keeping the hull geometry constant, where a boat of more displacement would have a waterline length multiplied by the cube root of change in displacement. And in this case, the wetted area would increase with an exponent of 2/3 (or the square of the cube root). So even then it's not linear, but it is significant. Double the displacement, and the wetted area is multiplied by 1.59 (approximately).

In the case you are actually considering, where the additional displacement is only increasing the draft of an existing floating shoebox (so to speak), then the wetted area may change very little.

[valhalla360]

Originally Posted by Stumble

I got it. How about we use electric propulsion and a bunch of batteries, then add back a 10kw generator to power the thing. With as many solar panels as possible. For just $40,000 you can only use electric propulsion.

If you are talking about ripping out a perfectly viable diesel propulsion engine and replace with the electric system...yeah, it makes no sense.

If you are talking about a new boat or replacing a dead propulsion engine, your $40k assumption is a bit high.

Let's look at the numbers for a canal boat with a 20kw motor (but only plan on using the extra power for quick bursts in locks and such otherwise keep it under 10kw) and 3500w of solar.
- Maybe $5k for the electric motor
- Assume $3/w for solar so $10.5k
- Battery bank, maybe another $5k
- Let's say another $5k for installation and integration.
- We'll assume both options have a generator and 10kw for house loads is fairly reasonable, so that's a wash but could be diverted to run the propulsion if needed.

Total $25.5k vs maybe $15k for a diesel....

If we assume 400hr under power per year (100 travel days at 4hrs) at 1/2 gal/hr, and $6/gal diesel prices, that's $1200 in fuel per year. Assuming the majority of run time is off solar power, figure around $1000/yr in fuel savings, so after around 10yrs, you come out ahead.

This ignores any generator savings if you are stationary as the combination of solar array and batteries is in the range where running air/con without turning on the generator is viable.

[valhalla360]

Originally Posted by Paul Elliott

In the case you are actually considering, where the additional displacement is only increasing the draft of an existing floating shoebox (so to speak), then the wetted area may change very little.

That fits in pretty closely comparing a steel boat designed to fit the canals to a similar hull also designed to fit the canals but made of fiberglass.

[valhalla360]

This might be a situation where charter canal boats might be the leaders. A one off EV canal boat has to expect to be self sufficient generating power. Until there is a critical mass, shore side facilities are unlikely to be upgraded to accommodate you.

If you have a charter base with 50 boats, you can put in sufficient power at the docks so they leave with batteries topped up. Assuming 1 or 2 typical routes from the base, you can invest in charging stations at common stopping points for a 1 week cruise.

You could then offer the client a fixed fee for power up front so they don't have to worry about a big fuel bill when they get back from the end of their vacation. That would allow you to skip the generator and just include a small solar array cutting the up front costs.

[Stumble]

Originally Posted by valhalla360

If you are talking about ripping out a perfectly viable diesel propulsion engine and replace with the electric system...yeah, it makes no sense.

If you are talking about a new boat or replacing a dead propulsion engine, your $40k assumption is a bit high.

Let's look at the numbers for a canal boat with a 20kw motor (but only plan on using the extra power for quick bursts in locks and such otherwise keep it under 10kw) and 3500w of solar.
- Maybe $5k for the electric motor
- Assume $3/w for solar so $10.5k
- Battery bank, maybe another $5k
- Let's say another $5k for installation and integration.
- We'll assume both options have a generator and 10kw for house loads is fairly reasonable, so that's a wash but could be diverted to run the propulsion if needed.

Total $25.5k vs maybe $15k for a diesel....

If we assume 400hr under power per year (100 travel days at 4hrs) at 1/2 gal/hr, and $6/gal diesel prices, that's $1200 in fuel per year. Assuming the majority of run time is off solar power, figure around $1000/yr in fuel savings, so after around 10yrs, you come out ahead.

This ignores any generator savings if you are stationary as the combination of solar array and batteries is in the range where running air/con without turning on the generator is viable.

This is what irritates me so much about electric propulsion boats... you just make stuff up with no sense of what you are actually going to accomplish and trow out imaginary numbers for everything to make it look good.

So lets assume your 20kw motor only runs $5k...

3,500w of solar works out to a predicted output of 3.5*5*.5=8.75kwh/day of generation.

If we have a $5,000 battery budget that works out to 23 Trojan T1275 12v 150ah batteries. for a total capacity of 41kwh nominal capacity. Of which 20.5kw is usable without destroying the batteries. The problem is that when you take Peukerts Law into effect and a 10kw load the capacity drops to about 75ah not 150ah, so the usable capacity drops to 10kwh.

Since we are working under the idea that the motor will be operated at a cruising speed of 10kw/hr. we can now make so good approximations of what this boats performance will look like.

With a 10kwh nominal capacity and a 10kw/h draw we can now predict that this boat will have a range under batteries of about 1 hour. Then because the batteries are at half capacity we will have to stop and recharge. Now we have 8.75kwh of recharging a day, and batteries that are down to 20kwh so figure it will take three full days of recharging to top them back off so you can get another 1 hour of run time out of the boat.

Lets assume just for fun that at 10kw/hr the boat makes 10kn best speed. so our average voyaging speed is 10nm/72hours=.14kn. Thats right this boat will make an average speed of .14kn per hour. This is roughy the same speed as a tortoise walking btw.

Your battery bank isn't anywhere close to large enough, you need massively large battery bank to get your run time up, not just for the raw capacity, but also because at this discharge rate the internal resistance of the batteries is going to chew up about half of the entire capacity. Not to mention discharging them this quickly over and over again is a fire hazard.


So lets redesign the system and increase the number of batteries to get the full 150ah rating of the batteries. That means we need a nominal capacity of 20 times the per hour usage. at 10kw/hr that means we need a nominal 200kwh or 112 batteries at an installed price of $24,500 (just batteries) and an installed weight of 9,520lbs. On the flip side we can now motor for up to 10 hours a day at our nominal cruising speed. But how long will it take us to recharge?

From a 200kwh bank we have now drawn down 100kwh, and will be recharging it with our 8.75kwh solar array... so it will just take 11.5 days to recharge the batteries from one day run time. So what is our average speed? Well it would be one days distance covered divided by the number of days it takes to recharge, or 100nm/276 hours=.36knots.

Thats a pretty slow way to get around anywhere. and the installed system is about $45,000.

[valhalla360]

Originally Posted by Stumble

This is what irritates me so much about electric propulsion boats... you just make stuff up with no sense of what you are actually going to accomplish and trow out imaginary numbers for everything to make it look good.

So lets assume your 20kw motor only runs $5k...

3,500w of solar works out to a predicted output of 3.5*5*.5=8.75kwh/day of generation.

Typicaly assumption for solar output is 4-5 hrs at he rated wattage, so figure you are off by a factor of 2. So closer to 18kwh/day

If we have a $5,000 battery budget that works out to 23 Trojan T1275 12v 150ah batteries. for a total capacity of 41kwh nominal capacity. Of which 20.5kw is usable without destroying the batteries. The problem is that when you take Peukerts Law into effect and a 10kw load the capacity drops to about 75ah not 150ah, so the usable capacity drops to 10kwh.

Wouldn't go lead acid for propulsion so Peukerts Law goes out the window. Lithium costs about double but you can use around 90%,
so yeah around 20kwh of storage.

Since we are working under the idea that the motor will be operated at a cruising speed of 10kw/hr. we can now make so good approximations of what this boats performance will look like.

You are the one adding that assumption.

I said to spec a10kw motor (later changed to 20kw to allow for better maneuvering in locks but used only in short bursts). I was figuring around 5kw average to maintain 4-5mph. That is very consistent with the power demand on our 34' catamaran where our 5hp dingy outboard could push it at around 3mph, so bump that up to around 7hp (5kw) and 4-5mph is about right


With a 10kwh nominal capacity and a 10kw/h draw we can now predict that this boat will have a range under batteries of about 1 hour. Then because the batteries are at half capacity we will have to stop and recharge. Now we have 8.75kwh of recharging a day, and batteries that are down to 20kwh so figure it will take three full days of recharging to top them back off so you can get another 1 hour of run time out of the boat.

With the corrected numbers, we have about 4hrs of run time add in a hour in locks (where negligible power is consumed) and that gives you a 5hr run time. The solar pretty much keeps up (if you travel every other day, you can even run the air/con off solar for a bit.)

Lets assume just for fun that at 10kw/hr the boat makes 10kn best speed. so our average voyaging speed is 10nm/72hours=.14kn. Thats right this boat will make an average speed of .14kn per hour. This is roughy the same speed as a tortoise walking btw.

You apparently haven't cruised the canals, it's a pretty leisurely affair. Turtle speed is typical.

Reality is you are closer to 0.6mph (FYI, they usually don't use kts on the US inland waterways) but really who cares. You can figure around 16-20miles per day which is about what you would do with a diesel traveling 5hr per day at 4-5mph.

Your battery bank isn't anywhere close to large enough, you need massively large battery bank to get your run time up, not just for the raw capacity, but also because at this discharge rate the internal resistance of the batteries is going to chew up about half of the entire capacity. Not to mention discharging them this quickly over and over again is a fire hazard.

Again, lead acid wasn't suggested. The "fire hazard" is just chicken little talk assuming someone halfway competent puts the system together.

So lets redesign the system and increase the number of batteries to get the full 150ah rating of the batteries. That means we need a nominal capacity of 20 times the per hour usage. at 10kw/hr that means we need a nominal 200kwh or 112 batteries at an installed price of $24,500 (just batteries) and an installed weight of 9,520lbs. On the flip side we can now motor for up to 10 hours a day at our nominal cruising speed. But how long will it take us to recharge?

From a 200kwh bank we have now drawn down 100kwh, and will be recharging it with our 8.75kwh solar array... so it will just take 11.5 days to recharge the batteries from one day run time. So what is our average speed? Well it would be one days distance covered divided by the number of days it takes to recharge, or 100nm/276 hours=.36knots.

Thats a pretty slow way to get around anywhere. and the installed system is about $45,000.

I'm not going to respond to the last few paragraphs as it's all based on incorrect assumptions.

You can certainly build a $45k system, but you better run the air/con 24/7 and be on the move dawn to dusk to burn thru the power you are collecting.

[valhalla360]

Originally Posted by Stumble

This is what irritates me so much about electric propulsion boats... you just make stuff up with no sense of what you are actually going to accomplish and trow out imaginary numbers for everything to make it look good.

Side note: I get what you are saying about being realistic. When people talk about electric taking over the coastal cruising market, it's a totally different story.

Current coastal cruisers (as much as it frustrates the sailing purists) expect to be able to motor 50miles at 6-8kts, get up the next day and do it again. They expect to be able to go flat out for a few hours if conditions get bad.

The difference here is canal cruising isn't nearly as demanding performance wise. Looking back at our summer on the Erie Canal our longest day was just over 30miles but most were well under 20miles. If you really wanted to be agressive, you could spec a small generator. Say a 3kw generator started when you take off, would put in 15kwh during the initial 5hrs you get from the solar system and buy you an additional 3hrs. In theory, you could keep it running during those additional 3hrs and buy anoher 2 hours. Since most canals shut down at night, 10hrs is about all you can expect to run during a day.

One thing I did miss is while lithium batteries do have a longer life,they do need to eventually be replaced, so maybe figure a 15yr payoff period based on fuel consumption to allow for a replacement set of batteries.