Sailboat powered like submarine

Richard, you have the right to call names anyone you like - from what I've seen it's usually deserving.

The biggest problem, as I see it right now, is to somehow make the same propr function reasonably well for both the electric and the diesel engine: an incorrect prop can do a lot of damage to the diesel engine.

In your experience, what's considered a safe DOD for modern AGM batteries?

 

The basic problem that makes any comparison to cars or bikes irrelevant is that a car engine never runs on the same high performance as boat engines. I have a Rupert Marine 50 and flat out I reach about 45 knots. She runs at about 32-35 knots in ECO and that will take about 75%-80% out of her engines.

Maybe you would not reach warp speed but most cars (unless you have a Ford Orion) are not possible to run at 80% over time. (You will die or spend a long time in jail.) Also hydrodynamics works a bit different to aerodynamics so when most cars will run more economic when slowing down, many boats will instead run less economic when doing the same. Someone mentioned subs so here is an example: An Amur-class missile diesel/electric sub has diesel range of 6000 miles in 7 knots (eco) and 650 miles in 3 knots (eco) in electric mode.

 

DOD (depth of discharge) is generally accepted as 50%. Hence my comment that your amp/hr rating is really only half (at best).

You'll get more cycles with shallower discharges.

The battery manufacturer usually publishes these numbers for their specific battery.

This will be part of your "balancing" and compromising within your design, desires and demands.

-Tom

 

Lithium batteries sure look cool:

http://evcomponents.com/cscart/index.php?dispatch=products.view&product_id=29845

 

Golf cart batteries are usually your best bang for the buck.

You may choose to connect them in series and/or parallel depending on your motor, RPM's, wire run length, controller, etc.

You are going to spend a good chunk of change to make this fly and at a considerable weight penalty.

Speaking of weight, can you imagine being hit by a flying golf cart battery or the amount of damage it could do if it ever got loose? Be sure and secure them really, really well while leaving enough room for thermal expansion. Oh yes, and there's venting too, especially if they get sea water on/in them. Hydrogen and oxygen are nasty bed-fellows around potentially sparking components...

-Tom

 

I wasnt comparing and you have a point. I was stating that the technological drive for advanced electric cars is a lot more than boats in what i have seen. And this could be due to the different working conditions in the marine field.
But having more efficient batteries is not a bad thing now is it ?

I will dig up some of the data i have read but i have very little experience in that area so im mostly learning as i go

 

Lookup Nigel Calders Articles in ProBoat, from about 2007 on. Saves time........

 

Not only do they look cool (I wasn´t aware that the styling of your propulsion would fancy you), they are most likely the cheapest solution as well.

 

Thanks Vulkyn.

Well, I am aware of that.............

And I would not say, that a 20miles something can be named a "range" regardless the boats size. Its just madness and PR hype.
But then again, I am a sailor and boatbuilder, not a dreamer.

Regards
Richard

 

submarines with sails

 

My typing skill failed me it should have been like this

Thx Apex.
Extrat, here is one of the pro boat articles on electricity, if you dig you should find more about this topic.

 

I knew people who had an electric conversion outboard on a transom bracket that used it for picking up and leaving your mooring lines, and getting home slowly in a flat calm until the low voltage cutout tripped. Then they started the inboard diesel. It was very effective.

Bio diesel is a low emission high energy density low CO2 solution. You still cannot beat hydrocarbons for energy density except for nuclear fuel. I doubt batteries will ever match the energy density life- emission- cost of producing bio diesel.

For voyaging there's enough of a problem keeping the batteries charged for in-house use, even with prop alternators wind gens and solar cells.

Electric low speed manuovering motors make sense to reduce your low power or cold engine run times when you just want to move a few hundred meters, but I'd suggest playing with an outboard.

A full diesel electric conversion is a different matter, they are good for low speed maneuvering, allow the engine to be mounted anywhere that suits the designer and work well with single engine multiple prop arrangements. You could motor low speed in a calm for a few hours with a moderate battery bank before recharging with such a setup, but you still have to pay the piper with hydrocarbons with efficiency losses at the end of the day.

 

My thoughts exactly! If they really are 3000 cycles at 80% DOD then they are pretty much unbeatable - lead acid ha no chance against it. Plus, they are much lightet - about 5 times lighter, to be precise.

As for coolness factor - I'm an IT nerd, so it's important.

 

Today I can only se one technology that have the potential to seriously replace gas and diesel in boats and that are hydrogen fuel cells. Fuel cells are the only alternative that´s able come near to store the same amounts of energy as gas/diesel.

Maybe you will find aplications for electrics as well but electric drives will, unless someone make some really fantastic innovations, never find any serious place in boats.

 

Only in theory Mike. And of course you know that.
When we play around with Diesel Electric or parallel Hybrid, we always end up with the additionl equipment as close as possible to the "conventional" part of propulsion.
The freedom to place a generator where we would like to place it, is just not there, it is theory.
I still have to see a "free" positioning of auxiliaries on a seagoing vessel. (yacht)
Additional in/outlets, exhaust lines, weight distribution, noise, all factors to limit the freedom, all forgotten when the optimistic PR picture of such systems is published.

Nigel Calder, sure a supporter (and co developer) of Hybrid systems recently summed it up.
He "sees potential in niches, such as canal boats and sailboats that will exploit the regenerative capabilities" and then: "the higher the house load, the better the Hybrid looks"

So, nothing new, not even the perfectly engineered and executed ZF/Volkswagen/Siemens installation, coupled with Li/iron batteries provides more than a few minutes of full power el propulsion, or a few hrs. at very low speed. Nothing one could call sensible onboard a open water craft.

And the, so often enthusiastically celebrated, regeneration (through prop) on sailing craft, is just cheating yourself. It can not be sensible, no, it is even dangerous, to screw up the speed potential of a sailboat by cutting the top 30% of speed, to charge a senseless ballast one would not need if these 30% were there.

A mad idea, with a high market potential.
Ever day one of the dumb arrives at the main station, one has to find him. That was valid in the past.
Today they come in bus loads to visit the Hybrid suppliers exhibition stands. Let them buy what is claimed. They don´t harm anybody, and they are fortunately never found at sea, they cannot afford sailing after spending a twentyfive years bunker cost on gimmicks.

But they do it with a clear conscience.

Regards
Richard