Hybrid Engines

[fastcat435]

To increase efficiency and speed and minimize fuel, maintenance cost and CO 2 emission African Cats has developed electric motor/generators that retract from the water if no charging or propulsion takes place.The numerous advantages are:1: The resistance while sailing is lowered and the actual sailing speed increases because no sail drives, propellers, props shafts or shaft supports are in the flow of the water and the result is lower usage of motors.
2: The motors are located closer to the centre of gravity making the yacht safer and more comfortable.
3: Folding or feathering props are expensive and no longer needed because they are lifted from the water when not in use.
4: The grounding is very limited so prop anodes will wear very slowly if at all.
5: The propellers do not corrode or attract growth decreasing its efficiency.
6: The chance of lightning striking the yacht is less because the grounding of the yacht is minimized.(studies learned that yachts with sail drives have a higher chance of getting struck)
7: The silent electric motors are located in the water under the bridge deck so noise in both the bedrooms and saloon is minimal.
8: When under power from one motor or charging with one generator while sailing the other prop can be lifted to decrease resistance.
9: When the props are fouled with Kelp ropes or fishing nets they can be cleaned very easy, just lift them from the water open the hatch on top and clean them.
10: We use brushless maintenance free electric motors that are built to IP 68 so they are waterproof and are even preheated to prevent condensation.
11: We do not have thru hull fittings or shaft drives under water so leakage is not possible.
12: Large 3 bladed light weight slow rotating propellers have a higher efficiency than the normally used folding or feathering props and this is possible because of them being retractable.
13. While motoring with the generator running the fuel consumption is less then with the standard diesel propulsion.
13: the efficiency is better because the props are not mounted close to the hull but at 3 ft distance so there is a better water flow.
14: the weight is substantially lower compared to the normal electric drive or diesel propulsion.
15: The optional generator is installed under the guest king sized bed in a sound capsule and this area is also insulated to keep noise to the minimum. ( measured 47 DB at 2m)
16: the propellers are counter rotating so there is no wheel effect and it increases efficiency because the rudders are now in line instead of counter steering the wheel effect.
17: the propellers are mounted away from the rudders so the rudders are more effective while sailing or generating power. ( and no vibration )
18: Spaces under the beds normally occupied by the engine/sail drive combination are now empty and can be used for other purposes or an extra buoyancy chamber can be installed.
19. When using the electric motors there is no exhaust smell, smoke, noise, vibration and you do not have to fill your diesel tanks each time when you dock.
20. If you are sailing too fast you can lower the props to increase resistance and slow down and in mean time recharge your batteries.
21. When beaching the boat you can raise the legs and there is no chance of damage to motors or propellers.
22. The controllers are seawater cooled to increase efficiency, keep the noise and heat to a minimum and the heated water is used to preheat the water in the water heater.
23. A water heater in 120 volts dc is included in the system to conserve more energy so it will not be necessary to first convert to 12 volt and then to 110 or 220 ac.
24. It is possible to motor sail and preset the motors to an rpm setting, when the speed of the boat picks up because of waves or increased wind force, charging starts automatically.
25. A range of 5 different electric motors from 4 up to 25 KW has been developed (compares with 13 up to 82 HP)
26. With a RS 232 or USB connection it is possible to connect the system to your radar, GPS or computer to monitor temperatures of the motor and controllers, motor rpm, torque, electrical consumption. So far with the Raymarine, Simrad and Navman system
27. The system has build in safety for overheating or stuck propellers, if overheating occurs first the motor output is lowered, if the situation continues it switches down until cooled.
The same is done with the controllers.
28. Maximum and minimum rpm settings can be preset in order to use the least energy or to charge most efficiently. Charging normally starts at 120 motor rpm and the max prop rpm is set to a little over max hull speed , for instance if hull speed is 9 knots and it takes 900 motor rpm to reach that speed max rpm setting is 950. It is a waste to set it any higher since 1100 rpm will only give you 0.2 knots extra speed but the consumption of watts is 30 % higher.
29. The cost of maintenance, fuel and downtime is considerable less compared with normal diesel-saildrive motors.
30. Because the shaft is connected directly to the motor on one side and to the propeller on the other side and no thru hull bearings or P bracket are needed the resistance is far less and the efficiency much better.
31. The motor housing is made from Marine grade aluminium 6053 and coated with Coppercoat/epoxy so corrosion is non existent and resistance is minimal.

This system will also be offered to other yacht builders both for catamarans and monohull installations because a retractable system for monohull yachts is also developed.
It will be offered under the name “GREEN MOTION HYBRID”

[Simon Slater]

Before making any decisions on the viability of any diesel Electric system, I would like to make sure that everyone reads Nigel's and Graeme's columns in profesional boatbulder magazine. They are available on line. By the way this is that best marine rag in the industry, especially if your a techie. I do not believe that we are doing anybody any good by suggesting any one solution is the answer to all of our problems.

[Alan Wheeler]

6: The chance of lightning striking the yacht is less because the grounding of the yacht is minimized.(studies learned that yachts with sail drives have a higher chance of getting struck)

Well that's a total load of rubbish.

10: We use brushless maintenance free electric motors that are built to IP 68 so they are waterproof and are even preheated to prevent condensation.

I really don't know about these motors, but I do know that Brushless Alternators seem to be less reliable than brush type ones.

12: Large 3 bladed light weight slow rotating propellers have a higher efficiency than the normally used folding or feathering props and this is possible because of them being retractable.

That statment doesn't make sense. Maybe somethng was lost in translation.

13. While motoring with the generator running the fuel consumption is less then with the standard diesel propulsion.

Also a very poor statment. It's nonsense. You can not make something from nothing. Making that statement is not apples to apples.

14: the weight is substantially lower compared to the normal electric drive or diesel propulsion.

What's a "normal" electric drive.

( measured 47 DB at 2m)

Another meaningless spec. 47dBWhat?? A, B or C weighted all can make enormouse differences in the sound. 2m distance is not the correct distance for a sound reading. It is 1m. Sound halves (-3dB) for every doubling of distance.

16: the propellers are counter rotating so there is no wheel effect and it increases efficiency because the rudders are now in line instead of counter steering the wheel effect.

Ummm??? yeah right. Huh???

17: the propellers are mounted away from the rudders so the rudders are more effective while sailing or generating power. ( and no vibration )

Come again?????

18: Spaces under the beds normally occupied by the engine/sail drive combination are now empty and can be used for other

Did the same guy that typed No.18 also type No.15??

19. When using the electric motors there is no exhaust smell, smoke, noise, vibration and you do not have to fill your diesel tanks each time when you dock.

And so the genny runs on?????

20. If you are sailing too fast you can lower the props to increase resistance and slow down and in mean time recharge your batteries.

Say what?? Oh yeah right. It's a cat.

22. The controllers are seawater cooled to increase efficiency, keep the noise and heat to a minimum and the heated water is used to preheat the water in the water heater.

Hell what are these. Reostates or something?? Heat is energy. Cooling it means two things. Energy is being wasted as heat and the controller aint efficient. Cooling the controller ain't going to make it any more efficient.

25. A range of 5 different electric motors from 4 up to 25 KW has been developed (compares with 13 up to 82 HP)

The guy needs to learn his math. 25KW does not equate to 82Hp.
25Kw / .750 = only 33Hp.

31. The motor housing is made from Marine grade aluminium 6053 and coated with Coppercoat/epoxy so corrosion is non existent and resistance is minimal.

So no one has told the guy you can't put copper on Aluminium. Yikes.

Sorry, but this thing thing is full of holes.

[GordMay]

Originally Posted by Alan Wheeler

Quote: ( measured 47 DB at 2m)
Another meaningless spec. 47dBWhat?? A, B or C weighted all can make enormouse differences in the sound. 2m distance is not the correct distance for a sound reading. It is 1m. Sound halves (-3dB) for every doubling of distance.

Allan is our resident expert on sound.

Noise measurement readings can be adjusted (A-weighted) to correspond to the phenomenon where people hear high frequency noise much better than low frequency noise. Legislation on workplace noise normally gives exposure limits in dB(A).
A-weighting serves two important purposes:
1. Gives a single number measure of noise level by integrating sound levels at all frequencies.
2. Gives a scale for noise level as experienced or perceived by the human ear.

[fastcat435]

Hello Alan
6.
Regarding the lightning strike possibility please do some reading , Since Sail drives are being installed the number of lightning strikes has gone up so one might think that having sail drives increases the chance of lightning strikes.
10. These permanent magnet brushless motors are designed to last without maintenance , the only parts that can wear are the roller bearings and they are designed for 100.000 hours. ( made by SKF)
12. Large 3 bladed light weight slow rotating propellers have a higher efficiency than the normally used folding or feathering props and this is possible because of them being retractable. These propellers are shrouded with a wing shaped ring to increase the propulsion and regeneration with 10 to 20 %
Normally on a fast high perfomance boat ( cat ) fixed propellers are no option because of the extra resistance, since these motors and props are retractable fixed more efficient props can be used .
13. Testing 2 identical FastCats 435 one installed with 2 x 30 Hp Lombardini motors and the other with 2 electric motors and a generator at a speed of 7 knots the fuel used was 55% lower on the electrical version while part of the energy generated was flowing into the batteries , at 8 knots speed the difference was reduced to 30 % fuel flow and no more charging of batteries. at 8.5 ( max speed ) knots the fuel consumption was 10 % lower on the electric version .
14. The Weight on the retractable version is around 155 kilo,s less than the shaft drive version, the parts tha bring in more weight are the drive shaft, p brackets bronze props and the water cooling of the inboard motors.
Compared with the diesel saildrive the weight advantage is 240 kilo,s not taken into account the extra fuel carried around to get the same range as the electric version.
15. the sound level is actually 47 Db @ 1 meter distance , the 2 meter was a typo
we are now installing the generator under the seat/nav station and have lowered the sound to 44 Db @ 1 meter incorporating a new ( better ) sound shield from Fisher panda.
17. We are talking about a catamaran and the retractable motors are mounted under the bridgedeck and therefore not in front of the rudders.
18 yes it was the same guy , the space where normally the motors are mounted are now empty because we use underwater electric motors.
19. We drive the electric motors by battery power for up to 5 hours , the gen set turns itself on automatically when the power level drops below 60 % and stops again when reaching 95 % we also have 860 watt of solar panels to keep the batteries charged plus a masthead mounted wind generator of 300 watts max output.

22. Controllers always consume some energy that is creating heat and this normally wasted heat we are using to make hot water that otherwise would use extra electricity , this increases the efficiency.
25. We work with power output at the props shaft while diesels do not take transmission losses into account .
with 2 x 9.6 Kw electric motors we reach the same speed as with the 2 lombardini 30 hp motors. This has to do with more efficient props etc.
31. Yoy are right copper on aluminium does not work so we put 4 layers of epoxy primer on prior to putting on the coppercoat. It is now insulated and works likje a charm.


Just closed the holes for you ?

Greetings

Gideon

[bill good]

Gideon,
I love the idea of electric drives for a cat. How long are the retractable pods? The strength of a pod & mount under a cat would have to be 2.5mtrs plus & would start being the design strengh of an aicraft undercart!!But so what it works on aircrafts!! Why the need for coppercoat on a retractable pod? The need for antifouling is eliminated if the leg can be stowed!! Lightning strikes--- Well you can test that one in a lab at any uni & I bet any self respecting lightning bolt would not care whether the hull was connected to the "earth" by a leg or not. I think a leg would provide a good conductive path if bonded corectly however & a boat with such bonding may fair better & have less damage than a boat without such a connection. ie it may be better to LOWER your legs rather than RETRACT them in a storm!! IF you want to "test" the product in TROPICAL WATERS Well send me some a couple of these Puppies to ME. I've got the boat, background & time!!

Regards

[bill good]

The only expence I never ever budget for is the diesel fuel!! It is NOTHING compared with all others!!

REGARDS Bill Goodward

[jscott]

Originally Posted by Alan Wheeler

Well that's a total load of rubbish.

I really don't know about these motors, but I do know that Brushless Alternators seem to be less reliable than brush type ones.
That statment doesn't make sense. Maybe somethng was lost in translation.

A squirrel cage electric motor is essentially a brushless alternator. So depending on what every it is the OP is talking about this maybe true if he referes to squirrel cage electric motor/generators.

Also a very poor statment. It's nonsense. You can not make something from nothing. Making that statement is not apples to apples.

What's a "normal" electric drive.

Another meaningless spec. 47dBWhat?? A, B or C weighted all can make enormouse differences in the sound. 2m distance is not the correct distance for a sound reading. It is 1m. Sound halves (-3dB) for every
doubling of distance.

Quoting noise levels at 2m is a very standard way of comparing different equipment. No shielding is used since it is assumed that the end user will apply shielding of the same effectiveness, for either installation. Not sure if OP means this or not.

Ummm??? yeah right. Huh???

Come again?????

Did the same guy that typed No.18 also type No.15??

And so the genny runs on?????

Say what?? Oh yeah right. It's a cat.

Hell what are these. Reostates or something?? Heat is energy. Cooling it means two things. Energy is being wasted as heat and the controller aint efficient. Cooling the controller ain't going to make it any more efficient.

All electronics run more efficiencly at lower temperature and the effect can be quite a bit. All high HP Variable frequency drives are essentially limited by the cooling of the transistors, Remeber junction temps can be 125 C with the heat sink fins at 40 C.

This is not what the OP refers to.

The guy needs to learn his math. 25KW does not equate to 82Hp.
25Kw / .750 = only 33Hp.

So no one has told the guy you can't put copper on Aluminium. Yikes.

Sorry, but this thing thing is full of holes.

Yes he has some holes in it, but so do you.

[Alan Wheeler]

First of all fastcat, I didn't realise this was you. So I apologise for being a little abrubt in my reply. I thought it was just a set of statments I was commenting on. I mean absolutley nothing personal in my comments. I do see this as good discussion and with this discussion, maybe some of my negative thoughts toward electrical propulsion maybe changed. Which I would love it to be. I want to see better systems, but so far I have not come across anything that totaly adresses the problems or claims that have been made out there in the world.

Regarding the lightning strike possibility please do some reading , Since Sail drives are being installed the number of lightning strikes has gone up so one might think that having sail drives increases the chance of lightning strikes.

As has been discussed here many many times. Lightening has just traveled several miles through open air. A few feet of drive in or out of the water is not going to be any advantage or disadvantage to the path of that electrical flow. It has also been discussed here many times, that even dangling a conductor over the side of your vessel, does more for the protection of your vessel than making your vessel more attreactive to a strike. So a saildrive in the water is not going to make your vessel that much more of a target. Saying that the increase of sail drives has increased in strikes is not a good argument. It could also be said that it is an increase in the number of boats on the water, so more chances of strikes occuring. A sail drive will have no more or less chance of a strike than any other hull with a conductive fitting touching the water. OK, so these drives can come clear of the water, and if there was not one single conductive point touching anywhere, maybe, just maybe there is a very small % of decreased risk, but with the unpredictablility of a strike, I wouldn't like to bet on that.

[Alan Wheeler]

10. These permanent magnet brushless motors are designed to last without maintenance , the only parts that can wear are the roller bearings and they are designed for 100.000 hours. ( made by SKF)

That is quite possible. As I said, I really don't know these motors, so it may well be the case. But as I also said, for some reason the brushless Alternators seem to be less reliable. I really don't know why. Maybe someone can tell me. So to rephrase the comment, just because a motor is brushless, may not mean it is anymore reliable as the original comment alluded to.

Point No.12 now makes sense.

[Therapy]

Originally Posted by bill good

Gideon,
I love the idea of electric drives for a cat.
IF you want to "test" the product in TROPICAL WATERS Well send me some a couple of these Puppies to ME. I've got the boat, background & time!!

Regards

ME FIRST!!

I will be happy to test one in none other than the lightening capital of North America.

PLEASE send me one.

[Alan Wheeler]

25. We work with power output at the props shaft while diesels do not take transmission losses into account .
with 2 x 9.6 Kw electric motors we reach the same speed as with the 2 lombardini 30 hp motors. This has to do with more efficient props etc.

OK I understand. But you have to admit, that original comment was not well stated. The only issue I still see with that is, there are still many variables in the statement. Lets say a 30Hp motor for instance, the actual output in the water is going to be determined by many variables. Gear ratio being the biggest. Hp of engine is not a good concept. Shaft Hp at the propellor would be a better figure perhaps. But along with the Hp, you have to include torque and at what RPM points power is is delivered. Now if the controller is really good, I expect the one major advantage of the electric drive will be, a very parrelell and flatish torque and Hp line over the entire operating RPM. Something that dos not occur in a combustion engine.
And the other point is, actual power required to push the boat to hull speed. I would bet that a combustion engien of the same Hp as the electric drive woudl also push the hull to speed. Where the differences come in is when you need the extra power, like into wind and sea's. My boat for instance, has 130Hp. Waaay over what is required to actually move her to hull speed. But a couple of weeks back, I was in a sea state that required all that power and I was only making 1.9kts headway when she is capable of 9kts at that power. I was sure glad I had that power that day.

All electronics run more efficiencly at lower temperature and the effect can be quite a bit. All high HP Variable frequency drives are essentially limited by the cooling of the transistors, Remeber junction temps can be 125 C with the heat sink fins at 40 C.

Yes and no. Depends on the temp. Temperatures high enough to reduce actual efficiency would result in high failure rates. Electronics should never be run up in those temperature area's.
It is good however, that the heat produced is also used for something else than just wasted over the side. However, this is also one concern I have for electric. There are many "losses" of energy. That heat could have gone into the drive system. Obviousely thechnology isn't there yet. But being able to get all energy to the drive is the key that has so far alluded electric drives. Hence the losses incured from generation to storage to conversion to propulsion. It does not add up to be any more efficient that direct coupling a Diesel to the drive via a gear box. The energy is just different.


I think one conclusion you should make from this discussion is, there are people out there that want to see an alternative propulsion system. Me included. Many looking for those alternatives tend to be very clever people. Maybe me not included. But what has been offered in the past has not fulfilled all the hype produced. If you really want to push a system like this, then publishing very solid specs I think is the real key. Especially for those of us that grumble when we order the McD's burger we see in the picture and get handed the very poor representation of that picture.

[jscott]

Originally Posted by Simon Slater

Bunch of reponses here

Ya these are lithium polymer batteries, scared the **** out of me at first. The numbers are outrageous. 80 kilos, 10KWH, $20k. 12 fed ex sized gooey packs all in a nice aluminum box. Ran the air conditiong all day long, wow. You are absolutely correct on overcharging, small meltdown occurrs, no where as resilient as lead acid.

AC induction genset is on the boat we just launcehed the electrical side of the genset is tiny, 10 kilos and 12kw. Very effiecient, very new, very leading edge, very scary for boat builders.

Simon

Who were the manufacturers of the battery pack and the ac induction genset??

[jscott]

Sorry never met a transitor curve that had a higher efficiency at lower temp then at higher temp.

[fastcat435]

Hello Allen
I understand one thing , the more conductive material on a boat in thru hull fittings the higher the chance of getting hit , we at African Cats standard install a lightning conductor on top of the mast that is connected straight down thru the bridge deck to a 14 mm dyform piece of halyard that hangs in the water , this can be lifted out when no lightning is present.Tjhis is done becasue it is assumed that lightning normally travels in a straight line .
Excuse my English it is not my native tongue I am dutch.
Regarding the Electric motors the absolute positive about running the generator is that it always runs at its optimum rpm setting where the fuel consumption is at its lowest
2900 RPM 15 Kw 230 grams of diesel per Kw if there is excess electricity generated it is stored in the battery , when the battery,s are full or @ 90 % the gen set switches of until needed again. we are able to generate 4 Kw with each motogen at a speed og 8 knots plus and there fore the use of the generator is very limited.
And yes you are right , we would all like to see alternative propulsion systems preferably without consumption of fossil fuels , noise, smoke, pollution and no maintenace on top of that. That is my aim and we are getting close.
We will launce the next retractable FastCat 435 in February / march next year and it is my goal to do 2 atlantic crossings without consuming any fossil fuels.
If you want I can keep you posted.

Greetings and have a good day