How to design a homemade boat electric motor from a drill

You can’t stop wondering at the engineering thought of ordinary people. And as soon as it was possible to guess to assemble a homemade boat electric motor from a drill. But he has long been successfully exploited, and in various design solutions. And there is a possibility that the tendency to manufacture such products will gradually grow.

Having collected the motor from a drill you will save a decent amount on the purchase of a finished motor.

The benefits of the electric motor of the drill

There are several reasons for this:

• not everyone can afford to buy a boat motor;
• environmental legislation strictly regulates the use of factory-made motors;
• homemade boat electric motor runs almost silently, which is very important for the fisherman;
• electric motors cost the user much cheaper than internal combustion engines.

Power requirement

The power of the drill for the motor must be at least 150 watts.

First you need to decide on the choice of drill. And the main parameter is the power of this device. If it is less than 150 watts, then using such a drill for the manufacture of outboard motor will be inefficient. In stagnant water, somehow such a motor will move the boat, but on the river it will be of little use: it cannot overcome the current. This is all conditional, since it is necessary to take into account both the size of the boat and the speed of the current. But practice shows that it is better to do a home-made electric motor on the basis of a powerful battery punch. As a rule, the perforator is equipped with a reverse and has several modes of operation. For the outboard motor is very important. It will be possible to regulate the speed of the boat when catching "on the track" (trolling).

Operating voltage

The second point, which is very important, is the operating voltage of the electric motor. It is erroneously considered that the best option is to use 18-volt cordless drills. But for the manufacture of boat electric motor is not so. Sooner or later, but the battery will fail, and he will have to look for a replacement. And how many of you will find such batteries? Only in specialized stores of power tools, and at a high price. This approach is impractical.

It is much easier to use a drill that operates from a voltage of 12 V. It is not difficult to find a battery for it. A standard car battery will do. And you can connect it using wires: in the boat, they will not interfere.

Necessary tools and materials

So, you have a drill available, so you can start making an electric motor for a boat. For this venture you will need:

Scheme homemade motor for the boat.

• square tube (20x20);
• 2 clamps;
• 2 gearboxes;
• metal tube (diameter greater than 20);
• rod for the manufacture of the shaft;
• metal sheet for the manufacture of the impeller;
• welding machine;
• Bulgarian;
• self-tapping screws;
• screwdriver.

The lifting mechanism for the impeller

First, you have to think of a mechanism that will allow you to raise the impeller above the water. The simplest solution is to weld a metal tube to the clamps, on which the base is pivotally attached, which is a frame of a truncated quadrangular pyramid, directed by a smaller base to the water. In the upper part of the base (the larger base of the pyramid) is fixed the bed for the bearing, the tube is welded to the lower part of the base. Through the tube and through the bearing shaft is passed.

It may even be a wire of large diameter, but its mass will be large enough that is not desirable. It is better to use a smaller tube. The second argument in favor of the tube is that it can be provided with bearings in the upper and lower parts of the outer tube. Friction will be less, and the vibration of the shaft in the pipe body will be practically eliminated.

Installing the gearbox and manufacturing the propeller

The battery at the drill should be 12 volts.

Gearboxes must be mounted on both edges of the shaft. Craftsmen recommend making the gearbox with your own hands for a specific type of electric motor to make the number of revolutions optimal. This will be quite difficult and too long. You can use the gearbox from the service technician or purchase it from the sales network. Only one condition must be observed when choosing a gearbox: the transmitting number should not be too large. Ideally, the gearbox should reduce the number of revolutions of the drill 5 times. Pessimists argue that such a number of revolutions is small, and the boat will not reach speed. We hurry to dissuade you: it will not affect the speed, but the motor will not burn due to excessive load.

The lower part of the pipe can be easily equipped using a gearbox from an old grinder. It remains to add to it the impeller. You can use a ready-made propeller from other devices, for example, a cooler from the power supply of an old computer. But such an impeller will not create enough water to move the boat. The propeller is recommended to be made of sheet metal.

To do this, we cut a square with a side of 30 cm out of a sheet of tin (at least 2 mm thick) and make 4 cuts in it from the center of each side to the intersection of the diagonals. Between the slits should remain a distance of 5 cm. You will have 4 "petals", the edges of which need to give a rounded shape. Give them the desired shape and deploy each blade at 30 degrees from their axis. If you use a gearbox from the grinder, then in the central part of the propeller you need to make a hole, and it can already be fixed to the shaft with the help of a fixing nut.

And now you need to connect the top gear directly to the drill. Well, if the shaft of the gearbox can be clamped in the head of the drill. Then the work is simplified to the limit: we clamp the shaft and fasten the drill to the base itself with the help of clamps. Sometimes the design of the base does not match the dimensions of the drill, so a tube is used to connect the gearbox and the electric motor. It should fit tightly on the gear shaft. To prevent the shaft from rotating inside the tube, a secure fit is necessary. For this purpose, make a through hole through the tube and shaft and secure them with a pin. You can also do when connecting the pipe with a drill.

The device is an electric outboard motor from a drill motor.

The self-made boat electric motor is almost ready for action: we proceed to its testing and tuning. It is not necessary to put him on the boat and immediately go around the pond. You can simply lower the impeller into any container with water and turn on the electric motor. You should feel the flow created by hands. Check out his work in various modes. If the movement is felt, then a homemade boat electric motor can be used on the pond. The motor during testing should work in the normal mode and create the usual background noise.

The design of an electric motor for a boat has two very serious drawbacks:

1. It is not possible to rotate the motor relative to the vertical axis. It turns out that to control the boat you will need to use a paddle, but it is not very convenient for fishing.
2. Boat motor own assembly is not yet equipped with convenient controls.

Revision and control improvements

The scheme and image of a homemade boat with a motor from a drill.

Both deficiencies are eliminated during the subsequent revision. First, the base is placed on the swivel bridge. The simple design is this: on the fastener, which is secured with clamps, in the central part you need to weld a bolt. Weld a piece of pipe to the base, the diameter of which is commensurate with the diameter of the bolt. The pipe is put on the bolt, and you will have the opportunity to turn the base with the electric motor.

A handle is welded to the base, to which the current supply regulator to the electric motor is displayed. It can be any rheostat. Drill with a little change, connecting its motor directly to the resistors. This design will be more functional.

You may have a question: is it possible to simplify a home-made boat electric motor constructively, in order to ultimately reduce its price and time spent on assembly? The answer will be: it all depends on what components you have in stock. Craftsmen recommend using flexible shaft to create electric boat motors.

The convenience of this design is positioned in that you can do without the gearbox. Torque from the engine through the shaft will be fed directly to the impeller. The problem of this design is seen in the fact that the friction of all elements of the flexible shaft in the protective casing is quite large, and this will create an additional load on the electric motor.

The second negative point is the number of revolutions: the motor simply will not stand for a long time. At least one gearbox you will need. You can do without only the upper gearbox. The shaft is fixed in the head of the drill, located vertically. The engine will rotate the shaft itself, which simplifies the design. At the bottom of the gearbox is needed, at least, in order to change the direction of transmission of torque.

How to calculate the load and what should happen?

Screw can also be made independently, turning it out of the metal.

It should be noted that a well-chosen gearbox is for the outboard motor almost the main condition for its long and reliable operation. The exact calculation of the parameters does not hurt you. This work is not easy, so it makes sense to ask for help from an experienced engineer. In addition, consulting an engineer will not only pick up the gearbox for your electric drill, but also other components of the structure.

Well, since there is no beside the noted specialist, then you have only two options: use the trial and error method or find the necessary information in technical publications. There you will accurately gather all the data on the characteristics of any gearbox. The craftsmen claim that the gearbox from almost any trimmer is ideal for the outboard motor. By the way, using trim parts for an electric motor is a very good idea. See for yourself: gearbox, shaft, protective tube - all in stock. It remains only to connect this design with the engine.

A homemade boat electric motor in any performance will cost much less than the factory equivalent.

But do not think that a full replacement is found. You will lose in other directions: speed, power, power reserve. Factory motors are able to work for a long time in various modes of operation.

The self-made boat electric motor, the design of which we are considering, is capable of speeding up to 8 km per hour (in still water), it lasts about 5 hours of work (with interruptions) for charging the car battery. Designed for such an electric motor lightweight boat with two fishermen on board. In many cases, such a motor will be the best option: a smooth and silent course, ease of operation and ease of transportation. Try this motor at work - you will like it!