Diesel/Electric Propulsion for Sailboats

JetPac

Thanks to Guillermo I contacted the UK distributor, www.fleetwatermarine.com


Specifications:

MODEL: #002150AA
ENGINE: 200 HP diesel, turbo charged, intercooled, direct injected
DRIVE: 250 mm (approx. 10 inches) diameter stainless steel water jet
COUPLING: Toothed Kevlar® drive belt system
COOLING: Fresh water closed system w/stainless steel heat exchanger
INTERCOOLING: Seawater to air stainless steel intercooler
BOLLARD PULL: 1,200 lbs + static pull
BOAT DEAD RISE: Accommodates boat dead rise from 5 to 24 degrees
BUOYANCY: Depends on boat dead rise and weight (generally 250 to 500 lbs)
WIDTH: 40 inches (102 cm)
HEIGHT: 42 inches (107 cm)
LENGTH: 56 inches (145 cm) plus mounting brackets
DRY WEIGHT: 930 lbs (422 kg)
BATTERY: Heavy duty 12 VDC, minimum 850 marine amps, not included
ALTERNATOR: 85 Ampere, 12 VDC, included
SHELL: FRP, high density core in impact areas, foam core in other areas, closed cell foam injected for floatation
THROTTLE QUADRANT: Single lever, cable 33C, approx. 3 feet more than would be required for a typical outboard installation, included
SHIFT QUADRANT: Cable 43C, approx. 3 feet more than would be required for a typical outboard installation, included
ENGINE GAUGES: Complete set included, voltmeter, ignition switch, tachometer, manifold pressure, water temp, oil pressure, warning lights, buzzer
ELECTRICAL HARNESS: Included with instruments
BATTERY ISOLATOR: Included (Allows simultaneous charging of engine battery and accessory battery [accessory battery not included])
BATTERY SWITCH: Not Included
HELM: Use standard outboard with feedback, steering cables require approx. 3 feet more than a typical outboard installation, included (excludes steering wheel)
MOUNTING SYSTEM: Included
CE CERTIFICATION: Fully Certified to EC Sound & Emissions standards
Retail Price: £18,794 inc VAT
Special Offer Price: £14,995 inc VAT

NICHOLAS BENTLEY-BUCKLE
Fleetwater Marine Ltd
Ocean Quay
Belvidere Road
Southampton
England SO14 5QY

Tel +44 (0) 23 8023 5421
Fax +44 (0) 23 8023 5436

Nicholas kindly sent me a CD demonstrating a Zodiac RIB fitted with the 200 hp diesel Jetpac. The most impressive scene was the last, where the RIB is gently driven onto its trailer and then with a little thrust moved up to the bow yoke. That would be expensive with propellers.

Pericles

 

Thanks to Guillermo I contacted the UK distributor, www.fleetwatermarine.com


And the thrust per gal of fuel is?

FF

 

JetPac

This from the CD.

2 persons , light gear. Cruising 25.5 mph 6 mpg. WOT 39.6 mph 3.53 mpg.
As above + 1000lbs. Cruising 22.3 mph 5.19 mpg. WOT 34.1 mpg 3.04 mpg.

Weight Time to plane
Stern Console
500lbs 500lbs 5 secs 34.1 mph

1000lbs 3 secs 32 mph

1000lbs 19 secs 37.1 mph

5 persons light gear, 2000lbs sandbags full tank estimated weight 3400lbs

WOT 29 mph 2.64 mph

Fuel consumption at no wake speed 0.3 gph WOT 11.2 mpg

Phone 386 - 676 - 7685 and request the CD.

Fred, not sure what you mean by "thrust per gallon". Bollard pull is 1200 lbs.

For me, the combined benefits of diesel fuel, lowish transom weight, very good control and improved safety, because of the absence of a chainsaw propeller, plus doing away with the complications of an inboard installation: all these points convinced me to go the JetPac route.

Pericles

 

Revetec Holdings Ltd. trades on the Newcastle Stock Exchange. http://www.newsx.com.au/prices_alpha.asp?nsxcode=&currentpage=1 They're a penny stock still, since they haven't turned a profit yet. As such it's a potentially risky investment, but the shares are out there.
(edit- man this thread is moving fast! this is in reply to Pericles in #75)

 

Fcfc, I have found the relevant piece of information...not that I believe in all they say, but some things should be true

As you can see, there is some common ground with the Lagoon, I mean in the choice of the motorization for the Jeanneau. The original diesel had 48hp and the electric engine only 16hp.

"Fischer Panda Whisperprop® System installed on a Jeanneau Espace 37 sailing yacht… She was re-engineered to operate electrically with a 14 kW Panda generator and a 12 kW (16 hp.) AZIPROP® Drive.

The original Perkins diesel engine had a rated output of 48 HP. With the new and more efficient electric drive motor (having only 16 hp. approx. 1/3 of the output of the original diesel engine), the newly equipped yacht could clearly maneuver with more power than before.

With a calm sea and no headwind, a drive/performance ratio of less than 0.5 kW per 1 ton displacement results in about 80% of the hull speed being achieved. The engine speed then could be reduced to a minimum according to the performance. Since the normal, mechanical boat transmission has only one ratio, the conventional diesel engine has to run at far too many RPM‘s in relation to its performance at the propeller.

The electric motor delivers up to 300% more thrust at lower revolutions.
As a result of the ideal torque curve from the electric motor, the DE drive is able to attain up to 300% more thrust when maneuvering at low speed than a conventional diesel engine/mechanical transmission system.

The Propeller speed is governed independently by the speed of the motor.
The speed of the Panda Whisper prop generator motor can indeed be freely adjusted to the required performance. The speed of the electro motor can be totally freely adjusted, irrespective of the speed of the motor. The performance of the diesel motor can be automatically tuned to the required drive performance. This is not possible in the case of a conventional drive; the diesel motor almost always runs too fast, since a mechanical gearbox on a boat does not have a gear change.

Up to 60% fuel is saved, if a diesel electric Whisper prop drive is used.
The total efficiency is better than a conventional drive as a result of its highly efficient component parts, the total efficiency of the electric system is without doubt better than that of a direct mechanical drive. "

Regards

 

I think FP's claims there might be just a bit on the optimistic side, but there are some good points.
An electric motor can be designed with its windings in virtually any configuration. If you want a perfectly flat torque curve, with constant maximum torque over the whole RPM range, you can do that. If you want constant power at any RPM, you can do that too. If you want virtually perfect efficiency, it's possible with enough care to get pretty darn close over a reasonable RPM range. You can balance the trade-offs in many more ways than you can with a combustion engine.

What's happening with that Whisperprop is that, as far as the prop's concerned, it's putting out more torque at lower speed than the diesel. Sure the diesel was 48hp... maximum. At idle speeds like you 'd use in the marina, it puts out- what, 12-15 hp? Compared to a 12 kW (around 16 hp) electric.... but that electric has a very high, very flat torque curve and is putting maximum torque on that prop at speeds where the diesel would be barely idling.

What you're doing is separating the functions of producing power, and turning the propeller. The electric can turn that prop at whatever speed you want, and whatever torque is needed to spin it at that speed. The diesel can run just hard enough to produce as much power as the electric is consuming- and so does not have to run at high RPM under low load, or low RPM under high load. It can always stay at the ideal RPM for the power that is needed without worrying about how fast the final drive is turning.

The key to making this work is that the individual components of the electric system- the generator, controller and motor- must be efficient enough that the extra losses in converting to electric energy then back to mechanical rotation, are less than the gains made by running the engine at its optimal RPM- and in many cases using a smaller engine as a result. Dedicated DE systems like the Fischer-Panda generally get this right; hack jobs thrown together from leftover industrial components rarely end up on the right side of that balance.

 

Marsmat and Fcfc, more information about torque and eficency, regarding an electric engine:

Translated from the French

"With a fast diesel, typical on the pleasure boats, the propeller from the Lagoon turns between 1200 and 1700 RPM. The propeller has a 12cm diameter with a pitch of 13.
With an electrical engine, the propeller turns at 600 RPM, but has a diameter of 18cm with a pitch of 19.”

From the September edition of “Voiles and Voiliers”.

Note: I have seen the propeller, and it is really big. I believe they are talking about the ray, not the diameter of the propeller.

 

That could be a big part of the improvement in efficiency, Vega (I'm pretty sure you're right, those dimensions are radius x pitch)... the big slow prop is inherently a lot more effective, wasting less energy in the creation of useless turbulence (btw, for any Americans around.... those props are 9.5"x5" and 14"x7.5" respectively).

 

I have looked fisherpando web site. I think they are technically correct. If you accept to sail by 70% of hull speed, power is reduced by a factor 5.

The hullspeed of an oceanis is 7.9 kts. at 70%, it is 5.5 kts.

If your only use of engine is low speed maneuvring in a marina, and cruising at 80% hull speed (around 6 kts for a 40") when no wind. The technical arguments of fisher panda are perfectly valid.

But, if one day, you are bored, and prefer to go upwind cargo like, with full power, instead of tacking in a channel, you will in a few seconds understand the difference between a 40 hp diesel engine and a 10 hp electric engine.

The torque of an electric engine only have influence for acceleration : the time you use to reach the speed. It does not influence the final speed. Say you need 10 hp to go 5 kts. Power is force * speed. The speed is the same electric, or diesel. The force also : it is the drag of the hull. When you start at zero
speed, (idle for diesel, or zero speed for electric), the rotation acceleration of the propeller is governed by the difference of the torque absorbed by the propller (the same electric or diesel), and the torque available at the engine shaft. The electric engine can have nearly full torque at zero RPM. The diesel engine need to reach RPM of max torque to deliver max torque. So the electric engine will reach 5 kts before the diesel engine. That 's what fisher panda claims "better low speed maneuvring".

Now, if you change a parameter, say a better efficiency prop for the electric engine, Then why don't you use the same prop for the diesel engine ? There are a bunch of cars and trucks that have every imaginable gearbox. Why not a diesel powered boat ?

 

"I mean in the choice of the motorization for the Jeanneau. The original diesel had 48hp and the electric engine only 16hp.

The original Perkins diesel engine had a rated output of 48 HP. With the new and more efficient electric drive motor (having only 16 hp. approx. 1/3 of the output of the original diesel engine), the newly equipped yacht could clearly maneuver with more power than before."

Sorta an apples and oranges comparison. The diesel is ordinarily run at a very small percentage of rated power . The 16 hp if needed in diesel would only be 3/4 to 1 gph.

"With a calm sea and no headwind, a drive/performance ratio of less than 0.5 kW per 1 ton displacement results in about 80% of the hull speed being achieved. "

This is normal, most any boat will travel at unity (sq rt lwl) with about 1 hp per ton.


"The performance of the diesel motor can be automatically tuned to the required drive performance. This is not possible in the case of a conventional drive; the diesel motor almost always runs too fast, since a mechanical gearbox on a boat does not have a gear change."

Without a gear change most cruisers select a "cruising prop" not the one specked by the engine Mfg , but an owner selected unit to get the required thrust at the lowest reasonable engine speed.

Lots of cruisers with the usual oversized diesel set up to operate at Unity at 1200rpm, not as quiet as electric but really pleasant to be aboard.
And 1200rpm is power enough to power a 100+A alternator for house/hotel battery loads, a mechanical refrigeration unit and power a watermaker.

Up to 60% fuel is saved, if a diesel electric Whisper prop drive is used

FANTASTIC claim, the test proof is??

FF

 

The new lagoon 420cat. It comes standard with electric engines and with no option for diesels.

It is said that this is only the beginning of a big revolution in the Beneteau Groupe. If this one is widely successful, we will have a lot of cruising Beneteaus running on electric engines.

They had sold more than a hundred boats by know. Next summer they will be everywhere, many doing charter work, certainly some in the Caribbean.

We will have soon plenty data to know how exaggerated are those claims.

Meanwhile the boat has been test sailed by independent Sail Magazines and they report a cruising velocity similar to the previous model with 2X40hp. That one has a max speed of 7.5K. The electric one has a max speed of 7.8K, but it can only maintain that speed for 1.3 hours, because the engines are running on the generator power +batteries power. Recharging the batteries and running only on the gen, the boat has a cruising speed of 7.0k.
Running at a very economical cruising speed (6.6K) the engine is only running at 60%.
The generator wastes 6.1L/H at full charge and about 2,5L/H at 65%.
We are talking of an 11T boat.
The speeds were measured with GPS.

They did not test sail the boat with bad weather, but the Guys from Lagoon say that the boat, against waves and 30K of wind can make 5K of speed, a value that is close to the speed in these conditions of the model with two 40hp engine.

I am following this with much interest (I think this is the future, for cruising boats). If anybody have bought one of these babies, I would love to hear a personal opinion.

 

There is a severe problem somewhere with the diesel engines of the lagoon 420.

My spreadsheet says that a 25000 lbs monohull , 41 ft lwl, should do 7.5 with 23 hp. And should go around 10 kts with 80 hp.

If the lagoon 420 cannot even reach hull speed (8.5 kts for a 41 ft lwl) with 7 hp / tonne, you have to explain the full story.

 

About your spreadsheet I don't know...about the rest, I am not exlpaining nothing, only posting the test results made by an independent French Magazine.

By the way, Lagoon says that the previous version of the boat with 2x40hp had a max speed of 7.5 and with 2x55hp a max speed of 8.5k. They say also that with those motorizations the boat wasted from 2 times more to 4 times more. They have been testing this boat in the last 5 years.

 

I am not contesting your figures. I am just saying that if you need 10 hp / ton to reach hull speed, you do not have a severe problem, but a catastrophical one in your propulsion design from an efficiency point of view.

And now, you are comparing an eletric setup with a diesel setup that have a catastrophical problem.

 

Fischer Panda Diesel Electric drive

Robert,

I recieved word from Fischer Pranda stateing that the diesel electric drive systems are not marketed or sold in the US. I was not given an explanation as to why.

I'm not sure if they are still doing there home work or not. Perhaps they are still treating it as a science project.