MINI ELECTRIC BOAT

Week 1: 

I began by researching the basic principles of electric propulsion and boat design. My focus was on understanding how electric motors work, the types of batteries suitable for small-scale projects, and the importance of hull shape in water dynamics. I also looked into how weight distribution impacts stability and efficiency, noting how these concepts might apply to the materials I had available at home. This groundwork set the stage for the hands-on part of the project. Here are some things I learned:

• Electric Propulsion Basics:

  • Electric motors convert electrical energy into mechanical energy, which drives the boat forward. The motor’s power and efficiency depend on the voltage and current supplied by the battery.

• Batteries:

  • Lithium-ion and nickel-metal hydride (NiMH) batteries are commonly used for small electric projects because of their high energy density and relatively low weight. 

  • Proper battery management is critical to prevent overcharging or overheating, which could damage the system.

• Boat Hull Design:

  • The shape of the hull affects how the boat moves through water. A streamlined hull reduces drag, making it more efficient. The boat's stability is influenced by the hull’s width and how weight is distributed across the boat (so placing heavy components like the battery closer to the center of the boat helps maintain balance and prevents tipping). 

• Materials:

  • Lightweight and waterproof materials are ideal! (So like plastic containers, foam, or light wood).

• Boat Propeller:

  • The size and pitch (the distance a propeller moves in inches during a single revolution, kind of like a screw in a piece of wood) of the propeller influence how effectively the motor converts rotational energy into thrust. A larger or higher-pitched propeller can generate more thrust but requires more power.

Week 2:

*First, I found some supplies for my boat:

1. A lithium ion battery I found in my dad's basement stash. 

2. A small motor that I also found in my dad's basement stash. 

3. A plastic drawer/container. Guess where I found it? (Correct- my dad's basement stash)

4. 4 empty plastic bottles + rubber bands. 

5. Some scrap metal + my dad's soldering kit. 

Then, I drew a layout of what my boat will look like. The propeller and motor will be connected together on the back (on the "chassis"), and I can put the battery on the inside of the boat. There is a cardholder thing on the front of the plastic box, so I'm planning to get a piece of metal to fold up and back (this will be the **chassis). And I'll also add a switch that connects to the motor, and connect everything with those clip-on wire things. 

*important note: everything I took from my dad's basement stash, I asked first. Please do not steal without permission from your dad's basement stash. 

**another important note: "chassis" is pronounced as "CHAH-SEE." You might not have known that. It is a tricky word. 

Week 3-3.5: 

This was the most fun (and difficult) part of my project! 

First, I attached my empty water bottles to the plastic container and put it in the kitchen sink. It floats, as expected. Then, I cut up a bunch of the scrap metal and stuck it on the back of the boat for the chassis. Then I punched some holes in it so I could fit the motor through the metal. Later, I had to bend the top of the chassis more so that the propeller axis would be able to stay underwater. 

Second, I cut out the parts for the propeller (the blades have to be set in a descending, clockwise direction) and soldered them together. I almost burned myself, since I haven't soldered in a while. Then, I soldered the whole thing to the metal rod/propeller axis. 

Third, I figured that the propeller wouldn't be really stable just hanging off of the chassis like a flopping fish out of water, so I decided to add another metal piece toward the bottom of the chassis to stabilize it (so the axis goes THROUGH it and then attaches to the motor). This took a while, since I had to add it on to my design and then measure out/solder the metal pieces I needed. 

Fourth, I decided to put my little tiny baby motor on top of the chassis slant, so that it's safely out of the water. I also decided to put the switch next to it too. The axis of the propeller will basically attach to the motor through the hole. However, I encountered a problem here because I didn't know how to attach my propeller axis properly to the motor end. Back to the drawing board! 

• I researched online and found something called "axial coupling" or "axis joint." Basically, it is a way to attach the propeller to the motor spindle that accounts for any "slight misalignment" between the motor and the axis. So if the axis slips a bit, it'll still be able to rotate. 

• I added this to my final design. 

Fifth, I borrowed the wire that my dad uses to connect his PC boards for work. I've worked with them before, so it was pretty easy. I soldered the ends on to the switch and motor, since that's where my wire clips will attach to (from the battery, which again will be inside the boat). 

Sixth, I put everything together! Take a look at the finished product below. 

Week 4: 

Okay, this was REALLY hard. 

Let me explain. First of all, what's the point of a boat if you can't control it? You'd probably crash into an iceberg. So it is important that my boat is able to turn. Therefore, I decided to swap out my old switch for a new switch (one that goes 4 directions). 

Day 4 (August 3) - In this phase, we will be adding and revising things on our boat such as different skills or techniques for how the boat runs. Today, we replaced the switch we put on yesterday with another switch. The main goal for today was to use a switch to make the boat go forward, stay still, and go backwards. If you push the switch upwards, the boat goes forward. If the switch is pulled down, the boat goes backwards. If the you push the switch into the middle, the boat stops. 

For this renovation, we mapped out the schematic of how the wires would be connected and then soldered everything together. In the end, the boat worked but because of two short wires sticking out, there was still a very minor fire hazard (according to my dad). In response to this horrible threat, I decided to use something safer and more stable that connected our switch to the boat battery. So I found a wire connector and inserted it onto the boat. Which is kind of sad because it would be cool, albeit very dangerous, to witness an explosion in a pond. I even suggested to my dad that he buy me a fire extinguisher. However, he did not approve of this idea because he is old and does not know how to have fun. 

I also put some oil onto the motor since the squeaking sound gets really annoying whenever the propeller starts spinning and makes my eardrums hurt. 

Week 5: 

Here is something to consider: suppose my boat is on open water and all of a sudden a crocodile (or shark, if it is at sea) lunges toward it. Perhaps the propeller will smack it away, but that is besides the point. What I'm trying to say is that I've decided to add a speed up/slow down capability to my boat, so that it can escape Terry the Crocodile when he goes on a boat-hunting rampage. 

Today, we added a wire wrap board onto the boat. Now, there is another switch and a knob that controls the speed of the boat so that the boat can go forwards or backwards, fast or slow. Up until now, everything has been relatively easy. Now we are going into a more complicated phase that involves more hardware and software work. 

We started by cutting the wire wrap board and inserting the appropriate equipment onto it. Then, we use solder and wire to "build" up the board. This process was a few hours long, so I'll spare you the details. We took off some wires from the switch on the boat and attached it instead to the speed-control knob that we had installed on the board. Then, we attached some wires to the battery. In the end, we were able to successfully control the speed of the boat, forwards or backwards. Now I just need to find a tiny, 3-inch human who is willing to be our boat captain.