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How to Make an RC Boat Out of an RC Car: A Step-by-Step Guide

Many people who are into RC sports have a few cheap or older RC cars lying around that they might want to use for a new project. Well, those people are in luck, because one of the cooler things you can do with a spare RC car is to turn it into an RC airboat.

So how do you make an RC boat out of an RC car? Here are the steps you’ll need to take:

· Gather supplies and tools

· Disassemble the RC car

·  Modify the battery box

· Create a waterproof box for the receiver assembly

· Create a Styrofoam base for the boat

· Create propellers and mount to RC car motors

With just a few simple tools, you can take an old dual-motor RC car that you have lying around (or buy a cheap one from any toy or department store) and build your own working remote controlled boat. Read on and find out exactly how to pull it off. 

Supplies and Tools Needed for RC Car-to-Boat Conversion

Before you get started on your RC car-to-boat conversion, you’re going to need to gather all of your supplies and tools ahead of time. Here is a list of the tools that you’re going to need to complete this project:


· Small screwdriver (must be small enough to be used on the screws of the RC car you’re cannibalizing for your project)

· Soldering iron

· Drill with small bit

· Hot glue gun

· Hobby knife

· Small table saw


· RC car (dual motor)

· Wires (get a variety of colors so that you have wires that match with the car’s interior wires for simplicity’s sake when making connections)

· Plastic clip box container

· Hot glue sticks

· Heat-activated shrinkwrap

· Styrofoam for the base (the kind used to cushion flatscreen TVs and computer monitors in boxes is ideal and makes a good foundation for a catamaran boat design)

· Q-tips

· Popsicle sticks (the small rounded kind that come with ice cream cups work well)

This might seem like a lot of tools for just one project, but many of these tools and supplies are fairly inexpensive or can be cobbled together from similar alternatives found around your home, as long as the general materials are similar.

You just have to be prepared to troubleshoot any unforeseen engineering problems that crop up as a result of substitutions. 

Components of an RC Boat

The final RC boat will have six primary parts: 

·  Styrofoam base: This Styrofoam base can be made out of any kind of Styrofoam, but the kind that is used to secure flatscreen monitors inside boxes is particularly good for this kind of project because the U-shape makes a good foundation for a double hull catamaran design. 

· Waterproof “cabin”: This is the part of the RC boat that will contain the receiver assembly and the battery box. Care must be taken to ensure that this box remains waterproof so that if the boat is capsized, the electronics of the boat have a much smaller chance of being damaged. 

·  Receiver assembly: The receiver assembly is one of the main parts that is salvaged from the RC car to put on the RC boat. This is the part that receives the electronic signals from the transmitter or remote control. 

·  Battery box and on/off switch: The battery box is connected to the on-off switch and wired to the receiver assembly. These operate as a single unit in the finalized RC boat. 

·  Motors and propellers: The two motors in the RC car are repurposed in the boat design and are modified with wooden propellers fashioned from popsicle sticks. 

· Transmitter (remote control): This is the other half of the electronics set along with the receiver that allows the operator to give signals to the boat and move it. The transmitter is kept from the RC car but is left unmodified. 

Some of these components, such as the propellers and the boat cabin, are constructed by hand. But others such as the battery box, the receiver assembly, and the motors will need to be stripped off the RC car in order to use them to build the RC boat. 

Disassemble the RC Car

The next step in transforming an RC car into an RC boat is to take the RC car completely apart. To do that, follow this procedure: 

· Unscrew the chassis on the bottom of the RC car using a small screwdriver and pull this part of the RC car’s frame loose so that you have access to the electronics underneath. 

· Remove the receiver assembly from the car until it is hanging free but still attached by wires. 

· Disassemble the car’s steering gear/mechanism and wheels. These parts of the RC car are not needed, so you should reserve them and set them aside for spare parts. 

·  Remove the car’s rear motor. 

· Remove the RC car’s gearbox. This is also an unnecessary part and should be set aside.

· Remove the motor in the front of the car. 

· Reserve the car’s battery box. This will serve as the foundation for the new receiver assembly on the RC boat. 

· Disconnect the RC car’s antenna. 

At this point, the RC car should be completely disassembled, and you’ll be left with a battery box that has four empty posts, two on either end, where the wheels used to be. The on-off switch should also be on the middle part of the battery box. 

Modify the Battery Box

Using a table saw, cut down either end of the battery box until it is squared off beneath the receiver assembly. Take care during this process not to nick any of the assembly wires, pull anything loose, or accidentally bang the receiver. Saw carefully to make sure that you don’t shatter any of the plastic pieces while making this adjustment. 

Create Waterproof Box for Receiver Assembly

 The next step in creating your RC boat is to create a waterproof cabin to act as a secure station for your receiver assembly, battery box, on-off switch, and antenna. The reason this is important is that if you don’t protect this part of the boat from the water, the minute you accidentally flip it upside down, you’re going to short out the whole shebang. 

Any parts of the RC boat that are electrified will have to be waterproofed in case the boat does tip over, which is not an unlikely scenario when creating handmade boats. 

Instead, buy a waterproof, transparent clip-lock storage box that is large enough to house the receiver assembly, battery box, and on-off switch. Once you have your waterproof box, you’re going to want to drill several small holes into the box just large enough for the wires of the receiver assembly to run through when the RC boat is completed. These holes will serve both the wires and the antenna. 

I know what you’re thinking—how can the boat be waterproof if you poke it full of a bunch of holes? That’s where the hot glue gun comes in. 

Here is the full step of steps you need to perform to create a waterproofed cabin for your receiver assembly: 

· Take your rectangle of packing foam and place it over the front of the receiver assembly (where the circuit board is). Fold it over the receiver assembly and glue it in place. This will help protect the receiver assembly in the boat. 

· Figure out how many wires you’re going to have extending out of the receiver cabin to the motors and drill holes for the wires. Once you’ve run the wires through (after extending them in the following assembly step), you will take your hot glue gun and plug each hole to help prevent water from leaking into the cabin and ruining your RC boat’s electronics.

Extend Wiring on Receiver Assembly 

In order for the wiring on your receiver assembly to be able to reach the two car motors on the boat once you’ve installed them, you’re going to need longer wires, and you’re going to need to solder your wires together. 

To extend the wiring on your receiver assembly, follow these steps: 

· Secure the receiver assembly to the bottom of the receiver cabin. 

· Join the ends of wires not attached to the receiver assembly to new pieces of wire. For the sake of visual simplicity, it’s best to find extension wires that are the same color as the wires you’re trying to extend, but any wire will do as long as it is of equivalent size. 

· Once you have made the wire joints, solder them together. Run the extended wires through the sides of the receiver cabin and secure them with hot glue

· Add heat-activated shrink wrap to the wire joints and shrink it down around the wire joints to protect the exposed area. 

· Take the wires and lay them across the battery box in a straight line where the joined wires are not being jerked around. Secure them with plenty of hot glue so that they aren’t dangling loose.

At this point, you should have a finished receiver assembly enclosed in the storage box with the two car motors dangling outside of the box. 

Create Styrofoam Base for RC Boat

The next step in completing your RC car-to-boat conversion is to create a Styrofoam base for your boat. An ideal piece of Styrofoam for this project is the type of Styrofoam mentioned above that is used to cushion monitors, but any Styrofoam will do as long as it is cut into a shape that is seaworthy and it is large enough to hold the plastic storage box containing the receiver assembly.

Once you’ve found a suitable piece of Styrofoam, use your hobby knife to trim it down into the shape of a boat. The pieces of Styrofoam used to cushion monitors already form a convenient U-shape that provides a good basis for a catamaran design. 

Other types of Styrofoam might be used, but Styrofoam is a better material than polystyrene. While polystyrene will also usually float, It is much messier to work within the workshop, and it is more difficult to get neat, clean-looking cuts with it. In comparison, Styrofoam is just as lightweight on the water, but won’t leave little white pebble dust all over your workshop and can be cut in smooth lines.

When cutting the Styrofoam, do your best to make sure that all sides of the boat are squared off and evened out to the best of your ability. Take your time—it pays to be meticulous during this step. This will ensure that the boat remains level on the surface of the water and that the electronics stored on top of the boat don’t end up falling in the water and possibly being submerged. 

It also means that you’ll end up with a more aesthetically pleasing final result, too. 

Create Propellers

In order to convert your RC car motors over to boat motors, they’ll need to be attached to a makeshift propeller. To make propellers, take two popsicle sticks and hold them over water boiled in a pot on the stovetop. This will soften the popsicle sticks enough that you can twist them into a curved propeller shape. 

Bend one of the propellers in one direction and bend the other propeller in the other direction. You’ll want one of the two propellers to be contra-rotating in order to propel the RC boat forward.

For a video demonstration on how to create one of these popsicle stick propellers, watch this video.

Once the propellers have been properly shaped, drill a small hole in the center of each one. Next, take two Q-tips and cut the cotton heads off of them, leaving only the plastic hollow sticks. Mount your propellers on these sticks and cap each propeller off with a dab of hot glue to make sure it doesn’t come loose.

Mount Receiver Assembly to Styrofoam Base

After you’ve completed your Styrofoam base, glue your receiver cabin to the top of the Styrofoam, being sure to leave enough room in the rear of the boat for the motors. Hopefully, earlier, you made sure that your wires would be long enough to extend through the receiver cabin, through the receiver cabin walls, and back towards the RC boat’s motors.  

Mount Motors to Styrofoam Base

The last things to be mounted on your RC boat are the motors, which should be mounted at the boat’s rear on either side of the U-shaped hull. Take your wooden propellers and attach the propellers to the motors until they overhang the back of the RC boat, then glue down the motors on the surface of the boat at the rear.

At this point, your RC boat should be assembled! 

Test Your RC Boat

The final step after assembling your RC boat (after making sure that all of the glued-together sections are completely dry) is to test out your RC boat in the water. You can either take your boat straight to a body of water such as a lake or a swimming pool, or you can give it a little test run in the bathtub first just to make sure it won’t capsize right away. 

Because the controls of a boat’s propellers are different than the controls on an RC car, you’ll have to fiddle around with the transmitter (remote control) in order to figure out which switches operate which motor. 

Flipping both switches in one direction should propel the boat forward, switching both switches in the opposite direction should cause the boat to reverse, and flipping one switch in one direction and the other switch in the opposite direction should cause the boat to turn around in circles. Once you’ve had some chance to practice with the controls, you should get a good idea of how the boat handles within just a few moments of operating it.

If your new RC boat runs low on juice, the batteries in it can be easily replaced just like an RC car. The great thing about this conversion is that the receiver assembly, battery box, and on-off switch remain as a single piece, so even though you have to do a lot of disassembly to get those parts, reconfiguring them is quite easy. 

Making RC boats out of RC cars is a good way to get in some practice in simple electronics modification and repair while giving you a fun project to complete in the process.

To see a full video breakdown of how to perform this RC boat project, check out this video!

Making RC Boats Out of RC Cars Isn’t Hard with the Right Tools

Converting an RC car into an RC boat seems like it should be pretty complicated, but the truth is with just a few simple household tools you probably already have in your garage or workshop, you can either take an old RC car you don’t use anymore and convert it for a new water-based RC project, or you can purchase a cheap RC car unit for the purpose of deliberately taking it apart and converting it into a boat. Either way this is definitely a fun project with a very cool outcome!