Solar Boat

Get Started. It's Free
or sign up with your email address
Solar Boat by Mind Map: Solar Boat

1. Materials

1.1. Wood

1.1.1. Balsa Easy to work (knife and pva) Light weight Absorbs water easily Needs to be sealed Tissue and Dope

1.1.2. Other Woods Great range of mechanical properties Can be expensive to purchase Often better suited to recreational boat modeling, not racing

1.2. Metal

1.2.1. Brass Strong and fairly cheap

1.2.2. Copper Won't rust but bends

1.2.3. Steel rusts

1.3. Other

1.3.1. Paper Lots of weights and strength Do we want materials that are easy to work with or will last a long time? Light weight

1.4. Are there other, less traditional materials that can be used?

2. Basic Physics

2.1. Drag

2.1.1. Higher Drag results in less Net Force in the forward direction, and thus less acceleration 4-5 degree trim angle leads to lowest drag Savitsky Planning Hulls 1964

2.1.2. Increased by Drag coeffient of hull Minimised through hull design

2.1.3. Increased by Submerged cross sectional area Thus higher mass results in higher drag and lower acceleration Minimised through hull design Minimised through reducing submerged hull

2.2. Momentum

2.2.1. Important for ramming into rival boat Boat must have higher momentum than rival boat to move forward after impact

2.2.2. Equal to Net Force multiplied by change in time Slower, heavier boats would have more time to build up momentum, but also less Net Force Could a heavier boat support a more powerful propulsion system? Both boats theoretically have the same amount of time before impact Therefore, the boat with higher average Net Force will have higher momentum J.L. Merium and L.G. Kraige, Engineering Mechanics- Dynamics, 7th Edition or Later, Wiley

2.2.3. Mass and Velocity important in momentum storage, not generation Mass and Velocity do not directly effect ramming capability After collison, a lighter boat would go faster with the Net Momentum of the two boats

2.3. Buoyancy

2.3.1. Experienced Buoyancy equal to weight of displaced fluid Elger, D.F., Williams, B.C., Crowe, C.T. &Roberson, J.A. 2013 Engineering Fluid Mechanics (10th ed.), Wiley

2.3.2. Mass of boat should be equal to Volume of the submerged boat multiplied by the density of water More hull that can be submerged results in higher allowable mass What is an appropriate balance between buoyancy and drag?

2.4. Center of Mass

2.4.1. Affects the stability of boat

2.4.2. preferred to be in a low, central location Would greater stability through extra weight at the bottom of the boat be worth the drag?

3. Regulations

3.1. Pool

3.1.1. North-South orientation (sun is at North)

3.1.2. Minimum water depth = 75 mm

3.1.3. Guide wire height is 275 ~ 325 mm

3.2. Performance

3.2.1. Sqrt(Hull length) x Sqrt(2) = Speed

3.2.2. 0.027 x weight of hull = Speed How large the boat is depending on how fast the boat can run

3.2.3. Hull shape is designed under aerodynamics

3.2.4. A guidance system is required

3.3. Crew positioning

3.3.1. Crew must face the direction of motion

3.3.2. Must be positioned in normal manner

3.3.3. A manikin as crew

3.4. Boat travel

3.4.1. A variable pitch propeller is allowed to use ref: SWINBURNE-BOATS-SESSION

3.5. Construction

3.5.1. No commercially available hulls

3.5.2. Propeller parts can be purchased

4. Adhesives

4.1. Anything labelled for out door use

4.1.1. Water resistant

4.1.2. Locktight Not good for hard plastics


4.2. Plumbers Tape

4.2.1. Does the excess weight when taking on water matter?

4.2.2. Sticks to itself

4.2.3. Hydrophobic Make it faster in water?


4.3. Velcro

4.3.1. Standard velcro Strong under constant loads

4.3.2. Elasticated velcro Better grip during movement Stretches up to twice its starting length


4.4. Other methods

4.4.1. Wire

4.4.2. Snap joints

4.4.3. Polymer clays and foams Performance in water?

5. Green = Prefered options

6. Propellers

6.1. Speed Efficiency

6.1.1. Bigger the boat, the larger the diameter of the propellers can be

6.1.2. High pitch good for high RPM

6.1.3. Cupped propellers= higher speed for lower motor RPM Would they even work for model boats?


6.2. Materials

6.2.1. Aluminium Best Need to be the best? Expensive

6.2.2. Brass Next best

6.2.3. Plastic worst, but good for testing?

6.2.4. Home made Make/Buy/3D print


6.3. Shroud

6.3.1. Can scale it?

6.3.2. Is it worth it?

7. Hull Shapes

7.1. V-shaped Hull

7.1.1. Cuts through water better (moves straight) Will Waves from other boats be a problem? Will we need a flat nose to batter boats?

7.1.2. Doesn't bounce on waves

7.1.3. Not very stable

7.2. Modified Displacement Hull (Modified V)

7.2.1. Smoother in waves than Displacement wanders more than V shaped

7.2.2. max speed = Sqrt(water line) + 1.34 (knots) longer water length = more speed

7.2.3. More efficient travel through the water

7.2.4. Can't build with laminate method because of shape

7.3. Hydrofoils

7.3.1. Uses airplane shaped fins to create lift

7.3.2. At least one porous material

7.3.3. Less drag than planing boats Will Solar panel provide enough speed?

7.3.4. 3-4 degrees angle of attack optimum for efficiency

7.3.5. Can pull off boat if waves are too strong

7.3.6. Have to be careful not to nose dive due to waves

7.4. Flat Bottomed Boats (Displacement boats)

7.4.1. Tend to wander wildly

7.4.2. Bumps badly with waves

7.5. MultiHull

7.5.1. Catamaran Have less space for storage Longer waterline, means they can go faster Planes at high speed, making things faster

7.5.2. Trimaran

8. Solar Panels

8.1. Power generation

8.1.1. Panels supplied by Swinburne

8.1.2. Nominal power of 5.8W or above 7.0V-1.0A Effective area of 350cm^2

8.1.3. Full dimensions of panel 160mm by 252mm

8.1.4. Multicrystaline solar cell

8.1.5. Power generated roughly proportional to light intensity What are the typical light levels for the weather we will be testing in?

8.2. Mounting

8.2.1. Solar Panel produces the most power when pointed at close to the sun as possible Mounting may be designed to be adjusted so that solar panel can be best positioned Given the date and time of testing, can the vertical angle be determined beforehand?

8.2.2. Must be secure to the boat to avoid falling off, breaking, or affecting the boat's center of mass

9. Construction Methods

9.1. Carving

9.2. Laminating

9.2.1. Cut the outline out of thin would then stack and glue can be mechanised

9.3. Bulkhead method

9.3.1. Create the skeleton shape then plank

9.4. 3D Printing

9.4.1. Not recommended by hobbyists because of poor finish

9.4.2. Time consuming to create large parts Do we need the strength of the solid plastic? Will the plastic be too heavy for speed?

9.4.3. Cost of filament varies

9.5. Do we want a light craft or a heavy one?

9.6. Fiber Glass

9.6.1. Needs a plug to be created

9.6.2. Best for making multiple identical hulls

10. Motor

10.1. Permanent magnet DC motor

10.2. Torque on motor shaft = Current

10.2.1. High torque = high propeller speed

10.3. Motor RPM = Voltage

10.4. Panel voltage = 7 V, then RPM = 7700 @max power= 5.37 W

10.4.1. How much voltage do we need?

10.4.2. Most efficient?

10.5. RPM = 7700 --> Torque 1.5 mN.m @18% sun & 8 mN.m @82% sun

10.5.1. How will it perform under various sun equivalent? ref: Scorpio boat panel + Favlhager 2232 6v motor

10.6. efficiency of 45%~65%, actual power is between 2.42 W ~ 3.49 W