Engine

Diesel Engine Tutorial

Growing up like most farm kids I worked my share of diesels in Case backhoes, Mercedes cars, International Harvester, and Ford tractors, but only replacing parts like starters, pumps and such. Until I got the Ford 7.3 for the submarine I had never messed with the fuel pump or glow plugs. You can read more about the Ford 7.3 here: Engine Tune Up

Having deciding to build a sail and charter work boat, I knew it was time to improve my skills. I did not want to be like the Captain of 20 years that we took our sailing course with and who had to call home when the engine would not start.

There are likely lots of good community college night courses on diesel mechanics, but I don't have the patience for spending my nights in a classroom, so I decided on a home study course and spent $3600 on truck with a 170 HP Caterpillar 3116 with 150,000 miles on it. It was the perfect comprehensive home diesel repair course. There was a chance that if we liked this engine it might be the engine we drop into the sailboat. At this point there that is not likely. While you can get after market rebuild kits for the 3116, they just don't hold up like other engines. Which is one reason why you can buy a whole truck off a lot with one inside for $3600. You can read more about our experiences with the Cat 3116 here: Tow Truck.

Boat Engine Requirements

Paul's boat is a 65 foot version of our boat and he is going to use a 50 Hp engine. That is small for the size of bout but right for Paul's type of sailing. We on the other had plan to do charter work, salvage work and operate an ROV so we will sometimes need to get somewhere quickly and sometimes have the power to keep up out of trouble on a lee shore. For us 170 Hp was likely too low to start with and now that our boat has grown to 70 feet, Jack, our designer is recommending something in the neighborhood of 200 to 250 Hp.

Whatever the HP, make, and model, the overriding requirement is that we need to be able to perform a complete overhaul using remanufactured parts without the block leaving the hull. After that, the engine must be economical to operate and have parts widely available.

Making Sense of Diesel Engine Specs

http://www.frontierpower.com/library/makingsense.htm

Engine Prospects

John Deere

Jack favors John Deere; www.deere.com, in part due to their use of sleeves for the cylinders that allow easy replacement if needed. The John Deere PowerTech 6068 Marine Engine or 6068SFM is a 6 cyl, 6.8 liter, turbo charged, electronic fuel injected engine available in 154 Hp for continuous duty.

6068SFM Performance Data - 6.8 liter	M1	M2
Rated Power--hp (kW)	154 (115)	236 (176)
Rated Speed--rpm	2300	2400
Low Idle Speed--rpm	650	650
Peak Torque--lb-ft (N.m)	741 (1005)	674 (914)
Peak Torque Speed--rpm	1600	1800
Fuel Consumption - gal/hr for specified rpm
2400	N/A	9.2
2300	7.8	7.8
2200	6.7	6.8
2000	5.1	5.1
1800 (M2 Peek Torque)	3.7	3.8
1600 (M1 Peek Torque)	2.7	2.7

The same 6068SFM engine is for rated at various HP depending on how it will be used. The only things that change is the higher HP engines flow more fuel and have a higher turbo boost setting.

The bottom line is that using lower HP will give you longer life and greater duty cycle. M1 ratings are 24 hour a day and 3,000 hours per year and M2 are for 16 hours a day. They also have M3 through M5 which would be good for a full-time sailboat, but since Seeker is for part-time charter work, then getting to a destination on time will sometimes be necessary.

The John Deere tractor series also uses the 6.8 liter engines. The 7430 is rate at 165 hp. The intercoolers are air to air on tractors but most everything else should be the same. So there is a possibility of picking up a engine out of a tractor.

Local John Deere Dealer

P & K Equipment, Inc.
15615 E. Pine
Tulsa, OK (918) 437-3193

CK Power
1100 Research Boulevard
St. Louis, MO (314) 868-8620

Cummings

The following Cummings models are in the correct power range:

Model	HP	RPM	Peek Touque	GPH @ Peek	Fuel System	Duty Cycle
QSB5.9-230 HD	225	2600	1600	3.1	Turbo Charged	Heavy Duty
6CTA8.3-M	255	1800	1200	4.2	Turbo Charged	Continuous
QSL9 - 285 CON	285	1800	1400	6.9	Turbo Charged	Continuous

The Cummings C-Series has replaceable cylinder sleeves and 97 and older models use a very reliable mechanical injector according to a trusted diesel mechanic. The B-Series for 97 and older also have the mechanical injectors but not the replaceable sleeves.

Note: Cummins 4BT conversion. The 4BT makes a mild 105 hp but a whopping 265 ft/lbs of torque

Transmission

Jack's recommendation is a transmission from Twin Disk; www.twindisc.com. The Twin Disc MG-5050, also well suited to the output of the JD 6068 TFM, retails (in 2001) for USD $3,570

Controllable Pitch Propeller

The benefits of controllable pitch propellers (CPP) specifically for a sailing/cursing/workboat.

The props speed vs. power can be adjusted according the the varying cargo loads.
Drag can be reduced or increased to meet the sailing conditions.
The pitch can be adjusted match meet the required rpm of a generator that is being powered from the drive shaft.
No reversing gear is required.
Prop walk can be reduced by reducing the pitch.
With a reversing gear and prop you can prop walk the boat in either direction.
Individual blades can be replaced.

Prop Sizing Data

Max allowable propeller diameter 34" - 36" Need 10% clearance between the blade tip and bottom to reduce noise.
Vessel Max & cruising boat speeds 12 knts max 10 knts cruise in 15 knt wind
Displacement, length & LWL of the vessel 40 ton, 20 ton cargo, 70ft, 54ft
Shaft length: 20 ft ??

Quote

Hundested; www.hundestedpropeller.dk, is renown for some of the best controllable pitch props so got a quote on a new system for a 70ft motor sailor is $66,913 plus shipping. Here is the actual quote. Needless to say I am no longer looking a new Hundested drive systems.

Pacific Marine Equipment
www.pmeseattle.com
-- Todd
Hunderstat
CPG-12 -- integrated gear box and pitch control but with no reversible pitch ability.
FRHP -- Pitch control box that is hydraulically operated.
FREL -- Pitch control box that is operated by a 12 volt electric motor, but it can only change pitch at 50% engine power.

Other Props

Max Prop
Martec
Bruntan Autoprop
Luke www.peluke.com 34" is $8,500
Flexofold Folding Sailboat Propeller www.flexofold.com Max is 22”

Examples:

76 Centreboard ketch, 200 hp at 2200 RPM; Cruising speed 10 knots Twin disc MG 507 gearbox driving a Hundested variable pitch VP 4 FRQA propeller with a drip free type shaft seal.

85' Ketch, Volvo Penta 180hp diesel (1982) Gearbox: low torque with twin disc transmission. Propeller: Hundested variable pitch propeller.

56 Motorsailer, 173-horsepower L1066T.2 Lugger marine diesel engine and Twin Disc transmission connected to the Hundested propeller.

65-foot, twin keel sailing vessel, Gardner 8LXB with a Twin Disc MG 509 reversing and reduction gear. This is a 13.93 liter in line 8 cylinder direct injection engine which develops 176 BHP at 1500 rpm. Idle is set at 450, and cruising rpm is 750 to 1000. Sterngear is a Hundested VP4-FROA Variable Pitch propeller system. Pitch control is from the pilot house.

Electric Drives

Recommendation from Emotion Hybrids site electricmarinepropulsion.org :

Emotion Hybrids site electricmarinepropulsion.org
Power output Torque Voltage Max, current draw Weight Length Width Max. prop diameter* Max. displacement Max. monohull length**	16 kw 120 lb-ft (160 N-m) 144 vdc 111 amps 130 lb (59 kg) 19 in (483 mm) 11 in (279 mm) 25 in (635 mm) 26 t (23.6 mt) 50 ft (15.2 m)

Emotion Hybrids recommends a 120 lb-ft motor for 26 tons, so Seeker with 40 tons would need about 200 lb-ft torque. Compare that to a John Deer 6068 with 741 lb-ft at 1800 rpm and it's easy to see that it's certainly less power. The 6068 will loose a lot of torque to the transmission but I doubt it comes anywhere near 541 lb-ft.

If we decided that 300 lb/ft is sufficient then we can get that from a 100HP DC motor. A 100HP Motor at 1750 rpm = 300 lb/ft torque:
T = HP x 5252 / rpm = 100 x 5252 / 1750 = 300 lb/ft

Bigger DC Motors do exist: Horsepower 100, RPM 1750/2000, Weight 1118 lbs, Cost $13,777. Pluss; Variable Speed DC Motor Drive, Input 230VAC Three Phase, Output 240VDC Armature, 100 HP, 330 Amps Cost $4,952.

-- www.driveswarehouse.com The cost is considerable because this is just the motor and not the generator/s. Used units with controllers are available for 25% of the new cost but these motors are not specifically designed for regenerative prop drive so they are not going to be as efficient or practical. A 35kw, 3 phase Onan diesel generator used will cost around $7000. The up side of this approach is that the boat's shop will need lots of electric power and so having a big generator would be nice.

DC Motors

Thoosa 17000 from Asmo Marine, www.asmomarine.com and also www.ngcmarine.com is a 96V, 200 amp, 17kW said to replace a 52HP-60HP engine. These use a cog belt reduction to the drive shaft. The motor works as a generator and charges the battery bank, while the boat is driven by sails or engine in excess of the motor's throttle speed.

Advanced DC #L91-4003 72-120 volt, reversible motor from www.evparts.com
Current Ratings: 130 amps continuous, 150 amps for one hour, 500 amps peak
Horsepower Ratings: At 96 VDC, 13.6 HP continuous, 15 HP for one hour, 26.4 for 5 min., 62 HP peak
At 120 VDC, 16 HP continuous, 17.9 HP for one hour, 31 HP for five min., 72 HP peak
One Hour KW rating: 11.4KW @ 96VDC, 13.5KW @ 120VDC
Weight: 85 pounds

Batteries

With a 200 amp draw at full power, it would be best to have a battery bank that would provide 200 amps per hour at 96 volts over 20 hours allowing for a constant 200 amp load without damaging the battery bank. A typical gel-cell is 12 volt, 55 amp hour, so 4 of then would provide 220 amp hours at 12 volt, and 8 times 12 makes the required 96 volts, so that comes to 32 batteries. At $165 each that comes to just under $5280 for the batteries on top of the $8000 for the motor and controller.

The upside to a lot of batteries is that they can be hooked up to a rectifier in order to supply AC power to the shop tools, and it provides a large capacity for storing power generated by solar panels, prop and wind. At 43 pounds each it is also 1000 pounds of ballast. They are 10 1/2" x 7 3/8" x 8 3/4" so it would be easy to put all of then in the top of one of the keels. Having 96 volt DC available also makes it possible to run some of the tools directly from a 96 volt DC motor.

Motors Controllers

"For many applications including heavier vehicles and heavy boats an electronic controller is necessary. For boats and low-speed vehicles (below 15 to 20 Km/h, 9 to 12 mph) we recommend those made by 4QD, the Curtis 1225 and 1227, the Sevcon Millipak 4QPM (all of which give forward, reverse and regenerative braking) and the Curtis 1204, 1205 and 1209 (single direction but can reverse or brake by use of switch or contactor; 12 volt versions of the 1204 and 1205 are available on request but are not listed in Curtis’s catalogue). The Curtis 1225/1227 and Sevcon are microprocessor-controlled and if you wish to alter their settings you need either a programmer or an adaptor and software to connect them to a personal computer."
-- www.agnimotors.com

Hybrid Electric Drive Installation

1968 Owens Yacht
42' Hybrid Electric Baldor Compound Wound DC
12HP, 72 Volt, 15" Prop , Contactor reversing
4 Trojan 360AH, 6.00 Volt, Lead-Acid, Flooded
4 360AH in series for 24 Volt
4+ Knots

First, I had twin Chrysler 440's gas engines.
I cut a sprocket in half and drilled some holes in one half and threaded the other half.
Put the sprocket around the prop shaft a few inches back of the transmission.
I used a compound wound motor so it would charge when the gas engine was turning the motor. I could take the chain off when I did not want to turn the electric motor.
I geared down with belts on one end of a jack shaft I put where the motor was mounted back to the prop shaft. --Jack.

Resources

www.electric-boat-association.org.uk

Electric Drive Example

http://boatbits.blogspot.com/search/label/Electric%20propulsion

Electric Drive Links

www.ngcmarine.com
thunderstruck-ev.com
www.electricyacht.com Only smaller units.
asmomarine.com ASMO Marine - DC Motors with regenerative controllers.
electricmarinepropulsion.org Emotion Hybrids - DC Motors with regenerative controllers.
glacierbay.com Marine DC motors, 20 hp - 800 hp, OSSA Powerlite www.ossapowerlite.com
abovethewaterline.net DC generators, solar panels, etc.
re-e-power.com Big trolling motors
fischerpanda.com AC and DC generators, DC is more efficient but more expensive too.
solomontechnologies.com for boats displacing up to 10 tons 16+ tons
polarpowerinc.com Web site sucks

Rules of Thumb

A kilowatt is approximately equivalent to 1.34 horsepower. So 141.74 KW * 1.34 = 189.93 HP

Forums

www.marineengine.com/cgi-bin/discus/discus.cgi
http://boatdiesel.com

New and Used Engines

www.dieselenginetrader.com
http://stores.ebay.com/YOUR-ENGINE-PARTS-EXPERTS