Hybrid Theory

[Jim Cate]

Minor comment:

The huge prop suggested as optimum is simply not practical for a sailing vessel. And the statement that a folder or feathering prop removes that worry ignores the fact that neither one is capable of providing regeneration.

As a practiced cruiser, this technology is still in the unobtainable bin IMO.

Jim

[pdf27]

Originally Posted by Jim Cate

Minor comment:

The huge prop suggested as optimum is simply not practical for a sailing vessel. And the statement that a folder or feathering prop removes that worry ignores the fact that neither one is capable of providing regeneration.

As a practiced cruiser, this technology is still in the unobtainable bin IMO.

Jim

As I understand it, most feathering props will provide regeneration by putting them into reverse for a quick burst, which locks them in the right position until you unset them by driving them forward briefly. And "huge" props aren't necessary - it's been a while since I did the calculations, but from memory a couple of inches on diameter gives you something like 5-10% fuel savings.

[jostalli]

Originally Posted by Jim Cate

Minor comment:

The huge prop suggested as optimum is simply not practical for a sailing vessel. And the statement that a folder or feathering prop removes that worry ignores the fact that neither one is capable of providing regeneration.

As a practiced cruiser, this technology is still in the unobtainable bin IMO.

Jim

And this qualifies as a throwaway comment as it is based on assumptions.

[Jim Cate]

Originally Posted by pdf27

As I understand it, most feathering props will provide regeneration by putting them into reverse for a quick burst, which locks them in the right position until you unset them by driving them forward briefly. And "huge" props aren't necessary - it's been a while since I did the calculations, but from memory a couple of inches on diameter gives you something like 5-10% fuel savings.

This has not been true of the ones that I have used on my boats or any of my closer friends boats. This does not mean that it is not a possibility, and I'd be interested in the design of a prop that has that feature.

And one must not forget that feathering props are inherently less efficient than other designs due to the lack of twist int he blade shape.

Jim

[Jim Cate]

Originally Posted by jostalli

And this qualifies as a throwaway comment as it is based on assumptions.

Perhaps you could elaborate upon this (throwaway) comment. What assumptions do you mean?

Jim

[jostalli]

Originally Posted by Jim Cate

ignores the fact that neither one is capable of providing regeneration.

As a practiced cruiser, this technology is still in the unobtainable bin IMO.
Jim

Sure. The first line I quote is incorrect as pdf27 explained that with feathering props you quickly put the motor in reverse to lock the blades open. Then the blades will rotate producing electricity. You said it was a fact that it is not capable of regeneration.

Your second line I quoted is simply an unnecessary jab at hybrid technology to try and squash the conversation.

[Stumble]

Originally Posted by jostalli

Sure. The first line I quote is incorrect as pdf27 explained that with feathering props you quickly put the motor in reverse to lock the blades open. Then the blades will rotate producing electricity. You said it was a fact that it is not capable of regeneration.

Your second line I quoted is simply an unnecessary jab at hybrid technology to try and squash the conversation.

If I put my feathering prop into reverse it will still feather. Even assuming a different prop will lock open I am not willing to burn out my transmission to generate power. I guess in an emergency it might be worth it, but not as normal operations.

[Jim Cate]

Originally Posted by jostalli

Sure. The first line I quote is incorrect as pdf27 explained that with feathering props you quickly put the motor in reverse to lock the blades open. Then the blades will rotate producing electricity. You said it was a fact that it is not capable of regeneration.

Your second line I quoted is simply an unnecessary jab at hybrid technology to try and squash the conversation.

Not to beat up on this too much, but the three designs of feathering props that I am personally familiar with (Martec, Hydralign, Autostream) plus second hand info on older Max Props do NOT work the way pdf27 claims. They feather (as they are designed to do) whether in reverse or forward when shut down. They will NOT be useful for regeneration. There may indeed be some design that does what he says, and I again say that I would be interested in finding out about it.

My second line is not a jab, it is a statement of fact: For my t ype of long distance/long term cruising the technology is not developed to a useful degree.

Your application may be different enough that it works for you, and then good onya, mate.

Jim

[pdf27]

Originally Posted by Jim Cate

This has not been true of the ones that I have used on my boats or any of my closer friends boats. This does not mean that it is not a possibility, and I'd be interested in the design of a prop that has that feature.

And one must not forget that feathering props are inherently less efficient than other designs due to the lack of twist int he blade shape.

Jim

Kiwiprop does (see Electric Drives) - I think I saw that once and assumed they all did. This is unfortunately an area where I have no practical experience at all, nor am likely to be able to get any for some years so the closest I can get to it is coming on here and asking questions. Too much of an engineering geek for my own good I think!
I know Bruntons did a special feathering/self pitching propeller for Hymar as well (E*Star or something like that) - I would assume that would need to be capable of regeneration, so presumably works in the same way.

[Hyprdrv]

I thought the report said the folding prop design was a new one.

Regen is an important function of EB's. I see anywhere from 2 to 6A while sailing and if your doing it for a while this adds up. A few years ago a big argument was the fact that the prop slowed you down 1/2 knot. personally my trim skills are such that I'm sure I'm loosing more than that above the water. Regen with an 18" prop on EG is worth the 1/2 knot lost. Never had the boat up above 12 knots on the bay here but figure I can get one hell of a charge running down some swells as attested by the delivery captains.

Steve in Solomon's MD

[pdf27]

Originally Posted by Hyprdrv

I thought the report said the folding prop design was a new one.

It does, they've now just started selling it (Autoprop Eco Star). Reading between the lines that's where they got a large fraction of their efficiency improvements at part load from, and they appear to apply to pure diesel engines too.

[Dockhead]

Originally Posted by u4ea32

Sailboats powering with diesel are far more fuel efficient than powerboats. Several times as efficient, like 800%, which is much more significant than 10% or 15% or even the 400% gain when maneuvering mentioned in the report. Sailing is far more fuel efficient than powering by diesel.

So the right way is a sailboat that you would rather sail than power.

This is quite unlike most cruising sailboats. Boats can be very fun to sail even in ghosting conditions. But that requires very high sail area to wetted surface ratios. Easy to do, but cruisers just choose not to have high powered boats. A stubbornly poor choice, in my opinion.

If you have a fun-to-sail sailboat, then your powering needs collapse to just getting in and out of tight marinas. Which would amount to a few liters per year, perhaps, so the efficiency of electricity over diesel, or diesel over gas, is truly a silly thing to worry about.

And the real epiphany is: getting in and out tight marinas is a lot easier with twin outboard engines than a single, especially a single inboard.

So after playing with this problem for many years, I finally came to the conclusion -- after Ibex, after several hours of Nigel -- I decided the best approach is two 15hp gas outboards. For at least the following reasons:

1) cheap to install
2) cheap to replace when they wear out
3) no electrolysis nightmares in marinas
4) no drag when under sail
5) easy to clear the prop when I run over a mooring line
6) easy to work on while standing up outside
7) gasoline is easier to find globally, as every panga and scooter uses gas, not diesel
8) diesel smells really bad, the smell makes most people sea sick
9) twin engine maneuvering is MUCH easier than with a fixed inboard single engine
10) outboards are much, much cheaper to repair, especially in remote places where pangas rule
11) outboards are virtually silent, without vibration, compared to diesels or gas inboards
12) high current battery systems are very dangerous!
13) easy to go with no generator with today's modern photovoltaics and efficient electrical devices (LEDs), as long as the refrigeration is very well insulated.
14) very small fuel tanks are good in so many ways.

If good electric outboards ever appear, then it will be very easy to replace the gas outboards. Solar can easily provide the needed juice to get in and out of the odd tight marina, or cruising through locks.

But using electric for sustained operation? Nope.

I like diesel engines very much, which have many theoretical advantages, but for applications not requiring lots of power for long durations --like smaller sailboats -- I completely agree with this analysis. Outboards have a number of overwhelming practical advantages, which you have nicely outlined.

I could add a couple more advantages:

1. No shaft seal/stuffing box, so one less hole in the bottom of the boat.
2. Light weight
3. Saves internal volume


And a couple of drawbacks:

1. Hard to design to keep the prop underwater in rough conditions
2. Weight at the very end of the boat

[Hyprdrv]

Stumble Said:

"Let's just be clear, Beneteau (my he owner of Lagoon) spent a huge amount of money and time bringing the electric catamarans to the market. Eventually they walked away from the technology because they couldn't get it to work within the expectations of their customers."

This was an interesting situation and a disappointment to many who purchased the Lagoon 420. I won't go into the details other than to say after the 410 was launched successfully Lagoon decided to go their own way and develope their own EB. It was proven that the 410 Electric worked and on paper it made sense to do it themselves so with a new hull design based on the installation of Lead Acid batteries in the lower part of the boat they ended up with a much more rounded bottom. More on that later.
Lagoon (and most of the larger manufactures) depend on selling their boats to the charter business they sold the 420E as a low maintenance boat that would require little attention because all would be automated. So they went about designing an EB around a 72V system. Now back then there was very little in the way of hardware and know how to build a "small" system off the shelf so ended up with some interesting promises and parts cobbled together. Automated systems today are a little flaky but back then they where a guess and a prayer and required tinkering to maintain the system properly. The batteries where nothing special, in fact I believe they where the same ones used prior to their EB's for house banks and on the 410's. So off they went with a new hull and a new system.
I don't have any idea of exactly how many where sold to individuals but the majority where put into the charter business. One of the first things I had heard was there was a major issue with the automated Genset controls to charge and then shut down the genset prior to overcharging the batteries. This was suppose to be corrected with a software update which seemed to take forever to come out. In the mean time boats where delivered to the Carib and the charter companies got a hold of them sending out clients who had little if no understanding (or cared) of a new system and promptly was killing battery banks. Along with this the range wasn't what Lagoon had said it was going to be. Lagoon through it's service department with The Catamaran Company stationed a full time "mechanic" to work on the boats. To add insult to all this the new hull designs rounded bottom was slowing the boat down. To satisfy their main clients, the charter business, Lagoon retrofitted diesel engines in a large portion of the 420's and also had to include private owners in the refit. To this day I have no idea how many are still Electric.

Lagoon recently published a special addition Magazine of the history of it's boats and owners received a copy. From the first model to the "Water World" boats and into some plans for the future. In there there was 1 line about the 420E that all it said was the 420E was ahead of it's time. There was NO MENTION of the 410E which really pissed me off but that's another story.

Was the system ahead of it's time?
Yes and no.
Yes it isn't "idiot proof". You have to pay attention to "different" things than an ICE (Internal Combustion Engine) boat. It's not a lot of differences but the main thing people kill on boats are the batteries. Now put a bunch of them on a boat and ignore them and your going to have a problem. Let's face it there are a lot of people out there that don't have a clue how their boat works let alone the electrical system.

No it doesn't take a rocket scientist to maintain or operate one. Just some common sense. Mostly about batteries and charging them. Nothing that a boat owner shouldn't know about their boat in the first place and maintenance that is the same just more of it in the battery department. More and more parts and systems are coming on line all the time.

Safety:
In my case I'm dealing with a 144V pack of batteries. ANY TIME I'm working on the battery pack I disconnect all loads. I wear rubber gloves, I have a switch to break the 144V into 2 72V packs. My terminals are covered and I only remove one cover at a battery at a time. All systems are protected by fusses and I do nothing until all of the above is double checked and I have a procedure thought out. There is no more danger than a typical house bank and for that matter a single "D" cell battery can get you just as dead under the right conditions. My "engine" room is spotless and dry.

There are a number of people out there that are converting boats of all different sizes to Electric Drives. Most are the 30' and under but are having a lot of success doing it. The reason this subject can easily go under "Theory" is because it is new to many. It gets my goat for people to say it doesn't work when I and many others see it does. Maybe we are looking for different results, might not be for everyone but if even a small number of tinkerers are playing with it and a few can improve on the system, some have business doing it, and we get that EB grin the hell with the rest of those saying "it just doesn't work".

The Bumble Bee is still flying!

Steve in Solomons MD

[EllesBelles]

Originally Posted by pdf27

The only motor I've seen which gets close to this is the Hybrid Marine system using a Yanmar engine, which appears to have a step-up belt drive from the shaft to the electric motor. However, they don't mention anything about propellers so I assume it isn't designed to allow this.

We talked to a high-level Yanmar rep, and he said Yanmar didn't recommend or support combining its diesel engine with a parallel hybrid marine system.

As much as we like the quiet and energy efficiency of the hybrid engine, until this issue gets worked out, and the diesel engine company supports this kind of installation, and we know the warranty on the diesel engine won't be adversely affected, we're going to wait, stick with diesel and not install a parallel system.

[tdoster]

Why not just do it the simple way and put a couple of electric outboards on the stern, which would be a far smaller investment and you still have electric for maneuvering and your tried and true diesel propulsion is unmolested in any way?