Alternative Propulsion Thread

[jjtctaylor]

Originally Posted by scotte

Also, previously it was said that the Green Motion system will have 12 hours of runtime without charging. Am I correct that has now been downgraded to 3 hours (or less)?

Hi Scotte,

Rather than dragging Gideon thru the mud or counteracting what was said or or current stats,........ why not take a look at a happy customer of another system RE-E-Power? Look at the Hurdle's performance data for Gemini 105Mc. As he notes the power consumed is half the rate per chart. That shows some idea of performance versus KW-H consumed.

E-Pod Range

I know Gideon has been trying different options to get range via KW-h to balance with the added weight. He has tried Valence, now Mastervolt Lithiums, and some AGM. So range depends on how fast versus amp-hours available for storage. On the flip side is some batteries recharge faster than others. The new Odyssee pure AGM's seem to have outstanding discharge and recharge rates. Gideon has not published and charts for his Green Motion systems as far as I know. So will wait and see when he is willing to publish his results. But can guess it will be somewhat in-line with Hurdle's experience.

JT

[fastcat435]

When I started designing the Green Motion system it was a inboard water cooled motor with AGM batteries and the price was about the same as a diesel equipped boat. During the development I ran into many problems like having a large prop (that is much more efficient) and the added drag these large props gave us (that is a killer for a fast boat and a cat has 2 of these). The limited energy storage capabilities of the AGM units and the added weight on these same battery’s. It t is a pity I cannot post spread sheets on this forum but the weight / capacity / price comparisons we have made show that although the initial cost of lithium’s are far higher , over a 10 year period they are actually a bit lower in cost assuming a life time of 4 years for the AGM units and the added weight of 800 kilo ( 1800 LBS ) make the boat slower and you will have to start your engines or motor in that is case faster. we now have 35 KWH installed in the Green eMotion with a 22 KW diesel generator 2 x 9.6 KW retractable motor pods and with this setup the system is ready, it is commercially available to a few pilot customers and the first systems are installed and are being tested. The average diesel motor looses around 30 % power between crankshaft and prop shaft. the poor matched propeller looses about 50 % minimum in transferring that power into forward motion. Some nicely made racing folding props actually lose up to 75 % according to Nigel Calder.( a quote from Nigel Calder in the sail magazine “On most sailboats even a well-matched three-bladed propeller is, at best, only 60 percent efficient. The other 40 percent of shaft energy is dissipated into the water to no useful effect. Some two-bladed folding propellers are as little as 20 percent to 25 percent efficient.”) Now lets assume a loss of 33 % on a 40 hp diesel engine from the crankshaft to the prop shaft that leaves us with 27 hp now assuming a 50 % prop efficiency and that is very high !!!( the prop needs to be clean ) we are left with 13.5 hp driving the vessel. We use slow rotating large specially designed props we use lose about 30 % and we are still working to get that lower with shrouding and other types of props.Also because these props are out of the water most of the time they stay very clean so the efficiency remains high. (I am sure all of you have at some time seen the effect of even minimal growth on a prop) It is a slow process to make a new propulsion system and I had no idea what I got into when starting this in 2003. Every part we use is specially designed for us or adapted for us, the motor , the controller, the generator, the hydraulic helical actuator and the props are all new designed. To save on weight even bolts and nuts ( aluminum / titanium) that are needed to fit the retractable drive leg are designed and salt water spray tested for us. With exception of the controller all are made out of 5083 aluminum to save on weight and making all seawater corrosion resistant. the controllers are water cooled to increase efficiency and keeping the size down , the generator has a total weight of only 202 kilo or 448 lbs almost half of other diesel generators with the same output, this generator does not only put out the needed 174 volts DC but also 3 KW @ 24 volts to keep the house batteries charged. In the final testing bed we have installed 4 x 300 watt of Sun Power solar panels , 3 of these charge into the propulsion bank the 4th charges the house battery. During testing so far we have seen a maximum charge coming from the retractable motor of 3 Kw per hour. Having 2 motors in the water would give us 6 KW per hour we have 3 hours @ 50 % power propulsion on board 6.5 knots without having to start the generator and not taking into account any charge from the solar panels .or a electrical range of 20 nm . I am not saying this system is the best, it all depends on what you want out of your boat, it is however a step on the way to a cleaner and possibly fossil free sailing. If your boat is only used for the occasional weekend trip the diesel is the way to go or a shore charged electric propulsion system, however if your aim is to make long ocean crossing trips this might well be a solution. 3 hours is not much to be able to motor around but 95 % of the time it is sufficient to do what is needed. Just think on how often you use your engine 3 hours or longer ?
Since I feel that the diesel consumed will be minimal the diesel quantity will be a lot less and this saves additional weight. Normally in a FastCat 600 liter or 160 gallons of diesel is carried on board for long trips , this is halved for the green motion system. Cooking is also done electrically so the 3 x 10 kilo gas bottles are also out of the boat. ( we installed a 3 burner induction stove and electric oven.) To make this test bed complete this cat is air-conditioned, heated has plenty of hot water storage and all the options one can think of to see if the system will carry all the loads. If the system proves not to be good enough I am out of a lot of money and time but at least I have tried to make a better propulsion system.
Do not forget we are talking sailboats and our main source of power is the wind !!!

http://sailmagazine.com/boatworks/en...eed_propeller/

[James S]

Good right-up Gideon

[Talbot]

Originally Posted by fastcat435

It t is a pity I cannot post spread sheets on this forum

You can

[sam_uk]

The single bladed propeller;
Single Oar propulsion - Yuloh, Ro, Scull...

[Dedzaboy]

Originally Posted by fastcat435

If the system proves not to be good enough I am out of a lot of money and time but at least I have tried to make a better propulsion system.

Unfortunately, if the system proves not to be good enough then your "pilot customers" are also out of a lot of money and time. I wish them luck.

[fastcat435]

I have attached a spread sheet comparing AGM and Lithium battery's both for propulsion and the service side .
These are the prices we pay and the cost may be different in other locations

[Dedzaboy]

Like I say, I wish them luck...

[Talbot]

Originally Posted by fastcat435

However the testing results show very good results

a range of 18.8 nm for a battery cost of 24000 euros would not ring my bell.

It also would not meet my Good Results criteria.

[Hyprdrv]

http://www.cruisersforum.com/forums/...ble-27411.html

Some more info

[fastcat435]

The all battery range depends much on the cruising speed at 7 knots it is 20 nm
at 6 knots it is 24 nm at 5 it is 30 nm all with out starting the generator or any charging taking place from the sun. Assuming that it is a sunny day with 800 watt per hour charge for 6 hours adding 5 nm to your range.
The system is not for all , only for the people that are environmentally conscious and use their boat for longer trips.

[senormechanico]

Gideon,

I appreciate all your work on alternate propulsion (for that matter also your boat design). Some day I'd love to be able to afford one of your creations.

Being in the market for a new folding prop for my Dragonfly, I'd be very interested in the data you found about various folding prop efficiencies!

I have the original Gori 2 blade folding prop with which I am not impressed.

Steve B.

[fastcat435]

Hallo Steve just 2 3 blade folding or feathering folding props stand out above all others and it is a price matter The 3 blade Flex O fold and the 3 blade Gori are both very good props
I have experience with both , the Gori has the advantage of an overdrive setting but is also more expensive , the Flex O fold has a very high efficiency, around 54 % and that is very high. In the last test I read this prop came out best over all.
You are always welcome for a sail

Greetings

Gideon

[Hyprdrv]

Gideon,
Any chance you will be at Annapolis this year?

Steve in Solomons

[gosstyla]

A little actual experience with props:

1. eLeopard a 43' Leopard
a. Glacier Bay diesel/electric with 1 x 25KW genset and 2 x 33hp electric motors. Therefore effective available power is 2 x 17hp.
b. Original props 16 x 16 fixed - believe they were standard issue for that Leopard when fitted with 2 x 40hp yanmars. With these props experienced much cavitation.
c. Glacier Bay expected appropriate props would be 20 x 14 or even 22 x 13
d. After testing several different props ended up with 17 x 11 3 baded flexofolds.

2. 47' Crowther design - my previous boat
a. Glacier Bay diesel/electric 2 x 25hp gensets and 2 x 33hp electric motors. Was selected to be somewhat comparable to builder's usual install of 2 x 50hp yanmars.
b. Glacier Bay original suggestion was 24 x 18 3 bladed flexofolds then changed to 22 x 18 due to possible tip/noise problem.
c. Actually installed 22 x 16 and was way too big.
d. Glacier Bay's next suggestion was 19 x 12s but decided on 20 x 11s with the thought they could be cut back if necessary. They were still slightly too big but decided to keep them for the passage from Valdivia, Chile to Ft. Lauderdale.
e. Glacier Bay's last suggestion was 17 x 11s which have been installed. Initial report from current owner is that these may be a good fit.

These 33hp motors are designed for 1100 rpm.