An Electric Auxiliary Engine for a Sailboat Using Renewable Energy A Capstone Project Presented at the 4th Annual Dayton Engineering Sciences Symposium Professor Russell K Marcks, P.E.

Impetus Behind This Project Do we integrate enough electrical into our mechanical curriculum? Do we integrate enough electrical into our mechanical curriculum? ME Magazine Oct 2005

Impetus Behind This Project Energy and Environmental Concerns While We Play Energy and Environmental Concerns While We Play Oil/Gas discharge of two-stroke operating at ¾ throttle for 15 minutes with no load

Impetus Behind This Project Apply familiar concepts to unfamiliar applications Apply familiar concepts to unfamiliar applications

Impetus Behind Project Promote Team Work and Communication Promote Team Work and Communication –Hull and Prop (4 members) –General Mechanical (5 members) –Charging and Electrical (7 members) Team Meetings Team Meetings Project Review Meeting Project Review Meeting Project Presentation Project Presentation

Convert original 15 hp gas engine to a DC electrical motor Convert original 15 hp gas engine to a DC electrical motor DC Motor must power craft from dock to hoisted sails DC Motor must power craft from dock to hoisted sails Craft to move at a minimum speed of 3 knots for approximately 30 minutes Craft to move at a minimum speed of 3 knots for approximately 30 minutes Alternative Energy based charging system to recharge batteries while sailing Alternative Energy based charging system to recharge batteries while sailing Emergency backup Emergency backup Design Criteria

Use Wind Generators, Solar Panels, Tow Generator or freewheeling to generate power for the battery Use Wind Generators, Solar Panels, Tow Generator or freewheeling to generate power for the battery Electricity must support all electrical systems required at night and during normal sailing operation (radio, cabin lights, nav lights, etc)‏ Electricity must support all electrical systems required at night and during normal sailing operation (radio, cabin lights, nav lights, etc)‏ Equipment may be replaced to optimize efficiency Equipment may be replaced to optimize efficiency 1978 sail boat optimized for today's products 1978 sail boat optimized for today's products

Determining Forces on Hull Drag on the hull ( F d ) Drag on the hull ( F d ) –F d =.5*C f *ρ*S*V 2 Force due to acceleration ( F a ) Force due to acceleration ( F a ) –F a =m*a –Decided on an acceleration of 0.1 ft / sec 2 (50 sec to reach max velocity) Force due to waves in the water ( F w ) Force due to waves in the water ( F w ) –F w =C w *ρ*S 2/3 *V 2 where V is wave velocity –Based on a moderate wave height (~4 to 8 ft) ΣF=F d +F a +F w ΣF=F d +F a +F w

Losses Propeller Slip Propeller Slip –Assumed 45% slip (typical for Sailboat) Lower Unit Mechanical Efficiency Lower Unit Mechanical Efficiency –Measured

Efficiency of the Prop Efficiency is a function of the slip and the pitch ratio (diameter/pitch)‏ Efficiency is a function of the slip and the pitch ratio (diameter/pitch)‏ Increases ΣF Increases ΣF

Losses Attached pulley & weight to propeller shaft (output)‏ Attached pulley & weight to propeller shaft (output)‏ Attached torque wrench to motor shaft (input)‏ Attached torque wrench to motor shaft (input)‏ –Multiple Trials –Increasing Weight –Plotted efficiency vs. Input Torque –Assumed 80% Efficiency Overall

Propulsion Calculations and Motor Selection Developed Spreadsheet For Propulsion Calculations Developed Spreadsheet For Propulsion Calculations Mars PMG 132 Mars PMG 132 –24V to 72V –110 Amp Continuous –200 Amp for 10 Min –Light (24.8 lb )‏ 85% efficiency at Running Speed of required ft/s 5.303hp to produce a Running Speed of required ft/s

Peak Energy Consumed at 51s Energy Consumed Per Second Decreases at 52s. (5.067ft/s)‏ Energy Consumption

Controller Components Controller - AXE 4834 Controller - AXE 4834 –24 – 48V –Current Limit: 300A –5 min rating: 200A –1 hour rating: 135A –Voltage 0.30V Throttle - Curtis type Potbox Throttle - Curtis type Potbox –Inexpensive ($85) –User Interface to controller –Controls current sent to motor Pre-Charge Resistor Pre-Charge Resistor Contactor Contactor Fuse Fuse Ignition switch Ignition switch

85% of Battery Life Will be Remaining after 30min Drive Time Battery Life Will Be Depleted After 86min Drive Time Battery Life Estimate

POWER GENERATION AND ELECTRICAL SYSTEM

Distribution of Power MOTOR HOUSE WINDSOLAR AC GENERATOR DOCKSIDE CHARGER BATTERIES WATER

Battery Power - Motor Motor Batteries: (8x) Group 31, 140 amp hour 12 volt, wet-cell, deep cycle marine battery 13.00" L x 6.75" W x 9.50" H, Lbs. Motor will draw 110 amps at design speed System is a 48V 280Ah bank. Since marine batteries should not be discharged below 50% charge, leaving 140Ah to work with. Propulsion team estimates batteries 15% discharged after powering the boat to a sailing position. This allows more power for returning and also providing less dependency on recharging tools while sailing.

Wind and Tow Generators and Controllers Wind Generator Wind Generator –Rutland 913 –Had highest output –Quiet in operation –Low wind start up –24 VDC multi-bank controller Tow Generator Tow Generator –Low start up speed –High output –Fresh water –24 VDC multi-bank controller

Charging Circuit

Electrical diagram for motor

House Amp Draw

House Battery and Solar Panel Selection House Battery: (1x) Group 27 (1x) Group volt, 110 amp hour 12 volt, 110 amp hour wet cell, deep cycle battery wet cell, deep cycle battery 12.00" L x 6.75" W x 9.88" H 12.00" L x 6.75" W x 9.88" H Lbs Lbs. Panels: Hatch and Radar-Arch Mounted Hatch and Radar-Arch Mounted amp-hours generated based on 4.5 hrs sunlight/dy amp-hours generated based on 4.5 hrs sunlight/dy

Radar Arch Analysis 1-1/2” x.120” Wall Tubing 1-1/2” x.120” Wall Tubing Stainless steel Stainless steel ABYC (American Boating & Yachting Council) standards require support for 200-lb load with no more than 12” of deflection ABYC (American Boating & Yachting Council) standards require support for 200-lb load with no more than 12” of deflection

Resultant Displacement

Stress Distribution

General Mechanical

Motor Mounting

Upper Intermediate Housing Input Shaft Seal has been removed The upper intermediate housing adapts the original gasoline engine to the lower unit. It is this plate that needs be redesigned to adapt the DC motor to the same housing

Lower Intermediate Housing Water Pump The lower intermediate housing remains. Note the water pump needs to remain to support the input shaft. The impellor is removed. Not the splined input which needs to be adapted to a keyed motor shaft.

Shift Rod and Water Passages Shift Rod Water Passages The lower intermediate housing with water pump removed. Cooling water enters around shift rod. Must block off water from DC motor while maintaining shifting capability.

Intermediate Housing Adapter Bottom of Motor Spacer Locating Rings Adapter Plate

Motor Spacer Top View of Motor Spacer Locating Rings

Crankshaft Modification Cut Here And here

Crankshaft Modification Secured by set screws Connecting Sleeve is fabricated Crankshaft is turned down and keyway cut into shaft

Housing adapter Bolts to existing lower intermediate housing Motor spacer will allow mounting of different motors if desired

Gas Engine Operation Water Enters Travels Across Bearing Housing Travels up through lower unit housing Fills Intermediate Housing Pumped throughout the engine for cooling

Modification of Housing Block off water intake port Drill Hole to allow oil to enter and fill cavity

Modification of Housing Block off water passage Drill Hole to allow water to escape cavity

Student Writing Assignment Installation / User Manual