Boat motor from a screwdriver with a gearbox from an angle grinder


Boat motor from a screwdriver

Screwdrivers are best for making boat motors. You should choose a device with an operating voltage of 12 V so that you can install a car battery with a capacity of 45-55 ampere-hours. The device is being finalized in an elementary way.

Cordless outboard motor based on METABO BS 18 LT 5.2 Ah screwdriver Watch this video on YouTube

Manufacturing technology

Boat motors from a trimmer are made in two ways: all parts, such as a propeller, are purchased or made by hand. The second solution will require more effort, but also less cost.

As such, the drawing is needed not for the drive itself, but for the manufacture of a homemade screw. The dimensions of the latter depend on the drive power and the weight of the boat. A propeller with parameters of 100*30 mm is quite capable of moving vehicles weighing up to 120 kg.

  1. It’s easier and faster to build a motor for a boat from a trimmer if you choose a model with a straight shaft. If a device with a curved shaft is used - a curved rod, it will have to be almost completely redone, since the steel cable, in principle, cannot transmit the delivery torque. In this case, you will need to make the tube yourself from duralumin, then press the bronze bushing left after disassembling the bent shaft into it, and insert a newly fitted plastic holder.
  2. A homemade screw is cut from a duralumin plate according to the drawing, the edges are sharpened. The blade must have a curved shape; to do this, they are bent one by one by 10 mm. The propeller can always be corrected by trimming or bending the blade more if its performance during testing turns out to be unsatisfactory.
  3. The screw is installed instead of the trimmer head. It is imperative to use a ring attachment, otherwise the blades may puncture or damage the boat material. The photo shows the screw fastening.
  4. On the Internet you can find ready-made kits for converting a lawn mower into a watercraft. It includes the drive and adapters to the shaft. The adapters are universal, which allows you to do without alterations to the curved rod and shaft. Often this kit includes a clamp. In this case, all the work comes down to assembling the modification.
  5. Control - starter handle, can be used from a trimmer. But if it is inconvenient, which often happens, it is replaced with any suitable switch - from a bicycle, for example.
  6. Homemade boat motors from a trimmer are secured with a clamp to the boat transom.

Lifting mechanism

The task of the lifting mechanism is to move the motor in various planes, both horizontal and vertical, in order not only to control the craft, but also to be able to lift the engine out of the water. The simplest design is a system of clamps with which the screwdriver is attached to the lifting mechanism. The lifting mechanism must be rigidly attached to the boat, especially if the boat is rubber. The clamps must have rings through which the tube passes, and inside the tube there is a shaft made of a steel rod of suitable diameter. To make sliding easy, bearings are installed inside the tube.

Gearbox and propeller

The screwdriver develops high speeds, but this is not necessary for a homemade electric motor for a boat, so a gearbox is needed. A gearbox from an angle grinder is the most suitable option. To attach the gearbox, the upper part of its shaft is simply clamped in the screwdriver chuck.

You will also need a propeller, which is best made of stainless steel, 2.5-3.0 mm thick. Do not use aluminum or plastic.

Procedure:

  1. First of all, a square blank measuring 30x30 cm is cut out.
  2. A square measuring 5x5 cm is marked in the center of the workpiece and diagonal lines are drawn through the corners. Along these lines you need to cut the workpiece to a small square.
  3. The 4 resulting petals are rounded and rotated at an angle of 30 degrees.
  4. In the center of the product you need to drill a hole for mounting on the gearbox.
  5. After this, the propeller is installed in its place and securely fastened.

Propeller for a screwdriver 2. Boat motor from a screwdriver Watch this video on YouTube

Materials and tools

When selecting equipment, you need to pay attention to two things: power and voltage. These parameters are fundamental, and the quality of operation of the finished electric motor depends on them. The power depends on the selected drill (in this case this tool is taken as the basis), so first of all you need to select this equipment.


When selecting a drill, you need to focus on its power. This figure must exceed one hundred and fifty watts. It is not worth taking a tool with lesser characteristics. In this case, the finished device will not work effectively in moving water (that is, it will not be possible to swim with such a unit on the river). It is best to use a cordless hammer drill.

The hammer drill is equipped with reverse and has several operating modes. This circumstance is important for the motor that will move the watercraft, since it will allow in the future to control the speed of the electric motor.

The second important parameter is voltage. Eighteen volt batteries should not be used. They are difficult to find and expensive. The best choice would be a drill that operates at ten or twelve volts. Such a battery is comparatively cheaper, and, most importantly, it is much easier to find on sale.

After choosing the optimal equipment, you can collect materials. To create an engine you must first acquire:

  1. An electric drill that will act as a motor.
  2. Clamps with which the drill will be attached.
  3. Gearbox. You can use an element from an angle grinder if you intend to install the motor on the transom of the boat.
  4. Round tubes with a diameter of twenty millimeters.
  5. Profiled pipes (20*20 millimeters).
  6. A round metal rod. It will be used to create an electric motor shaft.
  7. Sheet metal from which the screws will be made.

You will also need some tools:

  • scissors for cutting metal;
  • welding machine;
  • Bulgarian;
  • electric drill with a set of drills;
  • self-tapping screws with a screwdriver if wood will be used to create the motor.

After all the elements have been collected, you can begin to create an electric boat motor with your own hands. The whole procedure consists of several stages. Work should begin by creating a lifting mechanism for the impeller. In order for the future device to work properly, it is recommended to carefully follow the instructions provided below.

Motor made using a trimmer

Before you start making a homemade motor for a boat, you need to decide on the choice of base from which the engine and other parts important for assembly will be taken. In this case, a trimmer will be used. In addition to this option, there are many more that use everything, even an ordinary screwdriver.

However, the lawn mower wins in many respects, and the design of its engine is closest to the design of a purchased outboard motor. This is proven by the drawings that many craftsmen compared before choosing what to take as the basis for a homemade boat engine. And let's look at it like this:

  • An engine that will save a huge amount of fuel (as the lawn mower is used frequently). Moreover, it can be four-stroke, just like on conventional motorboats. However, this happens very rarely and it is mostly two-stroke
  • All manual gasoline mowers use a plastic and translucent tank, which allows you to constantly monitor the amount of fuel in it.
  • The internal part of the design makes it possible to easily convert it to a boat motor without much strain

The main difficulty when converting a trimmer is that the mower's engine will not always be able to cope with movement through water. This is due, first of all, to the different operating technology of each engine.

On a gasoline mower, it has a high number of revolutions due to the low torque. For a boat, the exact opposite is needed. However, this is easily fixed. But for this you definitely need tools (everyone has them) and drawings.

Basic list of tools required for work:

  • The trimmer itself is the basis of the future boat engine. Since most often a homemade motor is made for a rubber boat, having a small weight and size, the power of the trimmer can be small - about 0.8 kW. Even such a small power can provide an average human speed of 5-7 km per hour. However, if the motor is made for a heavier and more massive boat, you should choose mowers with higher power
  • A material that is ideal for making a screw (this can be done at home), most often it is duralumin with a thickness of about 2 mm
  • A vice or any other tool that allows you to secure objects (in this case, a motor to a boat)
  • Metal welding machine (any, but preferably semi-automatic)

From walk-behind tractor to boat

#1 rne700

Post edited by rne700: December 20, 2010 - 22:37

#2 rne700

Attached images

Post edited by rne700: December 21, 2010 - 08:42

#3 Steam

Helmsman 3rd class

#4 Munchausen

#5 rne700

If these options are for a suspension bracket, then how will the drive be for the vertical shaft of the leg? To do this, you need engines with a vertical shaft exit. + With such a reduction in reduction, you need a low-speed, large-diameter propeller (for traction), which is not currently produced. All screws on the hangers are designed for speeds >3000 rpm. On motolodka.ru, the topic of hybrids is constantly discussed. Maybe you'll find something useful there.

#6 rne700

#7 felt boots

I’m not planning a suspension, but something like a corner column so that everything fits under the transom sofa, and if I can’t find a screw, I can try to make it myself (I just need to find the correct drawing, maybe someone has it?)

#8 felt boots

. Belarusian (I don’t remember the brand) which had an aluminum connecting rod which was covered.

#9 TOSIK

Helmsman 2nd class

#10 Tap

I’m not planning a suspension, but something like a corner column so that everything fits under the transom sofa, and if I can’t find a screw, I can try to make it myself (I just need to find the correct drawing, maybe someone has it?)

#11 felt boots

Post edited by felt boots: December 23, 2010 - 16:36

#12 TOSIK

Helmsman 2nd class

Of course, I would like a diesel engine - there are fewer problems with diesel fuel, but I didn’t have much experience with such diesel engines except for the Belarusian one (I don’t remember the brand) which had an aluminum connecting rod which was damaged.

#13 Tap

Your propeller was a bit heavy. it was necessary to “adjust” it a little. for air-cooled internal combustion engines, such modes are especially relevant. A fixed corner column can be manufactured very easily with the simplest metal-cutting equipment.

#14 felt boots

#15 Steam

Helmsman 3rd class

#16 Steam

Helmsman 3rd class

Attached images

#17 Lebedev Veniamin

Helmsman 3rd class

#18 Lebedev Veniamin

Helmsman 3rd class

#19 Munchausen

#20 khron

#21 I&R

. Could you tell us in more detail about the design of the transmission itself?

#22 rne700

Tell me what kind of boat do you have? I have a self-propelled column made from two Neptune gearboxes. I can give it away “for a small share” only to a person who is really passionate about it. and will do this. The total reduction is about 3.

#23 Steam

Helmsman 3rd class

Now I’m thinking about about the same engine, using a Chinese 3.6 hp diesel engine and a belt drive, like yours. Could you tell us in more detail about the design of the transmission itself?

Making a boat motor from a chainsaw: step-by-step instructions

Let's look at the process step by step:

  • we remove the chain boom, in its place we install the propeller - the cutting mechanism is removed in a few seconds;
  • we are finalizing the coupling - for this a detailed drawing of the workpiece is made. We suggest using the ready-made one presented below. You can use roller bearings, as well as a shaft with a diameter of 7.8 cm;

we make grooves into which the staples will subsequently fit. To make them we need a metal corner. There is no need to take it too wide: a width of 2.5 cm is quite enough;

Using staples, we attach the components of the coupling - the cup and the upper part (lid). We secure the new structure with a screw holder. According to the drawing we proposed, the total length of the spare parts aggregated together will be 100 mm (this is the body itself, the safety shield). The height of the studs along the main axis should be 2.45 cm, and the interaxial range should be 3.2 cm. Between the shaft and the axis of the first stud in order, a larger distance will remain - 5.4 cm. To maintain these proportions, the stud must have a threaded diameter of 0.8 cm, and the thread pitch is not less than 0.1 cm;

We aggregate two working shafts - one from the gearbox, the other from the motor. To do this, take a sector-key;

  • connect the gasoline engine to the shaft. A channel is useful for this; with the help of a grinder, it acquires the desired configuration;
  • we drill holes with a drill to install fasteners that will prevent the structure from falling apart during operation;

attach the chainsaw - the back side of the shaft should fit onto the threads of the gearbox, which can be removed from the old grinder;

we manufacture the rotary unit in accordance with the diagram proposed below;

We attach the screw, which will create a flow of water, to the gearbox shaft - it is advisable to take a ready-made one to save time;

  • fill the gearbox with transmission lubricant, secure its cover with a handy sealant;
  • We install the chainsaw motor on the boat and carry out the first tests.

If desired, the structure can be additionally equipped with a throttle handle for more comfortable control or a muffler.

The resulting homemade motor will allow you to develop a power of 3.3 hp. This is enough to move through water at a speed of 10-13 km/h and consume about 750 ml of gasoline per hour of operation.

Maximum persistence with little time and material costs will allow anyone who wants to acquire a similar motor for a rubber or plastic boat, which, with reasonable operation, can last up to 6 years.

How to make a boat motor from a chainsaw with your own hands?

Having prepared all the diagrams and tools required for the work, you can proceed directly to assembling the outboard motor.

The work algorithm looks like this:

First you need to remake the factory clutch of your existing chainsaw. To do this, you will need to machine a cup of the required dimensions, and also replace the standard spring. For example, if you have a suitable metal shaft, 2 roller bearings marked 941/12, and 2 parts of type 7000 CD at hand, then a machined cup with a thickness of 16.5 and an outer diameter of 78 mm is suitable for assembling a boat motor. This cup will interact well with the roller bearings, showing stable performance with reduced friction. To attach the cup, you will need three brackets, which must be fixed in the grooves. To make staples, it is best to use a metal corner, in which one side is made in the shape of a trapezoid and is 25 mm in length. Using staples you will need to connect the coupling cover and the cup. After this, the mounting brackets must be clamped with a washer and a screw; After the completed steps, the height of the finished structure, taking into account the screen, body and distance to the base plate, should be no more than 10 cm. The distance from the first standard pin to the shaft should be equal to 5.4 cm. Since the total weight of the structure will be about 4.5 kg, then to fasten it you will need to use a pin with a metric thread applied to it with a pitch of 1 mm and a diameter of 8 mm; To mount the shaft and the motor used, you need to prepare a channel. Using a grinder, you will need to cut a piece of suitable size from it and drill a hole in it for the bolt. After this, all that remains is to connect the chainsaw to the finished structure; After this you need to make a swivel unit. For this purpose, you need to take a piece of metal pipe, the diameter of which will be several millimeters larger than the diameter of the shaft. Also, to assemble the unit you will need a pre-welded corner, a hollow metal guide with six edges, a metal blank with a rectangular cross-section and a strong metal rod of the required diameter. You will need to cut out a handle in the workpiece, the edges of which should be cleaned. Then, threads will need to be cut at the ends of the rod used, after which the entire assembly must be installed on the shaft and secured in the most convenient place for this; In the end, all that remains is to adapt the gear shaft with the screw used for assembly. If this part is not available, you will need to make it yourself. To do this, you need to cut a blank from sheet steel into which epoxy glue and fiberglass should be poured. After this, the finished screw will need to be deburred and painted.

When making a propeller for a boat motor from a chainsaw, it is very important to observe all the dimensions and proportions of its blades. Otherwise, one of the parts of the screw will be subject to increased load, which will cause the element to break very quickly.

https://youtube.com/watch?v=n1H4olf_30E

It should be noted that homemade boat motors made from chainsaws are designed to move a rubber boat with two adult passengers at a speed of no more than 20 km/h. If you regularly increase the speed, this will lead to excessive load on the chainsaw engine. It will quickly overheat and fail. As a result, the owner of the chainsaw will have to change all the seals, the cylinder-piston group of the engine, and also re-adjust the carburetor.

Homemade products, what you can do with your own hands, where to adapt the gearbox

A significant number of mechanisms operate at shaft speeds after the grinder gearbox. there are more options for using an angle grinder gearbox for the operation of other devices . Together with non-standard ways of using an entire grinder for homemade projects, masters of technical creativity create interesting compositions . Some are presented by the authors in specially filmed videos.

To the trimmer

Owners of summer cottages and garden plots will be interested in the following video. Many of them use trimmers to maintain the area in proper order. The possibility of failure of the electric motor installed on such a device cannot be ruled out. The author suggests using a grinder instead. Why is a bracket made from waste materials, which is mounted in place of the burnt out engine. In addition to the bracket, you should make an adapter from the angle grinder spindle to the flexible trimmer shafts. A grinder is attached to the installed structure and the trimmer is ready to mow overgrown grass.

The number of revolutions of such a modernized design is about 10,000 rpm . At such speeds, grass mowing is carried out quite efficiently. It is possible that the use of grinders of the minimum power range to reduce the weight and overall characteristics of the trimmer will lead to overheating of the grinders during operation. You should monitor the temperature of the grinder gearbox and take breaks if necessary.

Cultivator drive: Mole and more

Land owners will benefit from the experience of the author of the following video. of the cultivator failed . In its place, the author came up with a mount for the grinder and connected the spindle of the grinder gearbox to the cultivator gearbox . The speed of the grinder is certainly higher than that of a gasoline engine. However, the performance improvement advertised by the author is unlikely to occur. The problem of overheating of the commutator motor will remain and frequent stops, as a protection against it, will remain. Although for owners of relatively small plots the use of such a cultivator will be effective.

Machine

One of the structural elements of the drilling machine is a gearbox from an angle grinder (!you will learn how to disassemble the gearbox here). Working in tandem with an electric motor from a washing machine makes it possible to obtain drill speeds in accordance with the required technological conditions for processing materials. The rotor of the angle grinder is cut to the length necessary to securely fasten the rubber bushing, which acts as an elastic coupling. The other end of the bushing is attached to the motor shaft. Fastening is done using clamps.

The machine has several degrees of freedom . In addition to lifting up/down using a handle and spring-loaded suspension, the lever system allows you to change the location of the cutting tool in the horizontal plane. It is advisable to use it as a tabletop device for making holes in metal and wood parts.

Plasma cutting attachment

A plasma cutter is used to cut round pieces. The frame structure, as shown in the following video, serves as a device for securing and adjusting the diameter of the resulting workpieces. The “trick” in using an angle grinder gearbox is that its conical pair changes the direction of rotation by 90° . Thus, the manual drive creates rotation in the horizontal direction, and the gearbox transfers it to the vertical direction and ensures the correct functioning of the plasma cutter.

What is an attachment for converting a trimmer into a boat motor?

Motors for light boats are often made from trimmers.

The main ones are the following:

  1. A clamp for installing a homemade structure with a trimmer on a prepared boat transom has become widespread. This option is considered more affordable, but is characterized by increased efficiency in use. The special design allows the device to be used as a propeller. When performing the usual function of a motor, the mechanism is small in size, easy to install and remove, which determines its very wide distribution.
  2. Propeller screw. This version is a little more complicated than the previous one, but there are already ready-made mechanisms on sale that are characterized by increased efficiency in use. It is not recommended to carry out the most powerful version, since due to the resulting draft, a light PVC boat can simply capsize. Often, the delivery package includes a special drive made using corrosion-resistant steel, as well as some adapters that make the trimmer an almost universal boat motor.
  3. Another common option is to convert a standard mower into a motor used to create traction. In this case, it is recommended to give preference to common trimmers that require gasoline to operate. The relatively light weight of 4.5 kg is a significant advantage of this design option.

Let's celebrate! When choosing, you should take into account the operating principle of the design. The wrong trimmer will not last for a long period.

Principle of operation

When considering a trimmer, attention should be paid to the fact that such a mechanism ensures high rotation speed of the blades. This ensures a high speed of movement of the boat through the water.

The features of the operating principle include the following points:

  1. The blades are turned outward.
  2. A motor installed at the top transmits rotation to the blades.
  3. To increase reliability, the shaft that connects the engine to the blades is located in a protective tube.

Let's celebrate! The higher the trimmer is, the higher the speed developed. The main disadvantage of such a motor is the loud noise during operation. This factor is very important at the time of fishing, since the noise can scare away all the prey.

Benefits of using a trimmer

The trimmer has a fairly large number of advantages that determine its popularity.

Let's call the main ones:

  1. Relatively low cost.
  2. Easy to install and dismantle.
  3. Light weight.
  4. High speed achieved when moving.
  5. High power rating, often excessive.
  6. Economical.
  7. Initially there is a gas handle and a starter.
  8. There is a special leg that allows you to adjust the power of the device.

These and many other qualities determine the fairly widespread use of trimmers recently.

Motor control and other design options for its creation

Although the electric motor is ready, it is not yet capable of cornering. In order not to turn with the help of oars, it is necessary to make minor modifications to the design. It is enough to attach a bolt to the central part of the mount, onto which you then put a pipe. This will make it possible to make turns by changing the position of the base and, accordingly, the electric motor.

You can weld another handle to the base, connecting it to a regulator responsible for supplying current to the motor. It would be advisable to use a rheostat. However, in this case, you will have to slightly change the drill itself by connecting the motor located in its body to a rheostat. This will allow you to create a more functional design.

Screwdriver as a motor

There are several ways to make an electric motor. Instead of a drill, you can use a screwdriver. In design, it is almost no different from a device with a drill. A distinctive feature of the product is its lower maintenance cost. So, one twelve-volt battery will be enough to operate the device for six hours. However, you will have to sacrifice speed due to less power.

In order for a sailing vessel to move faster, larger pitch propellers can be used. In addition, as in the previous case, the electric motor based on the screwdriver can be equipped with handles that make it easier to control.

Trimer electric motor

A trimer is also perfect for this purpose. Using this device will make the process of creating a motor much easier. The only thing the technician will need to do is shorten the length of the device and attach a screw to it. There is no need to mount the gearbox.


There is also no need to modify the control and system responsible for powering the motor. The only difficulty that may arise along the way is the problem of attaching the device to the boat. Especially for the inflatable one. But it can also be solved.

As an electric motor, you can use the units that power the windshield washers, or a simple electric motor. In the latter case, power supply difficulties may arise, since standard motors operate on an alternating voltage of two hundred and twenty volts. The problem is solved by installing an inverter.

Thus, the owner of the watercraft can create an electric motor for the boat with his own hands. You don't need any special skills for this. You just need to purchase the necessary materials and prepare some tools. It is recommended to use a drill with a power of more than one hundred and fifty watts as a motor. This indicator will allow you to move the boat both in still water and along the river. In addition to a drill, you can use a trimmer or a conventional electric motor. Another option is an electric motor based on a screwdriver. Such a device is cheaper to maintain, but problems may arise with the speed of movement of the craft.

Homemade boat motor from a drill

  • Availability of battery as a power source.
  • A propeller with a gearbox sets the craft in motion.
  • The engine controls are a reverse button and a rotation speed control knob.

But it is worth remembering that moisture penetration into the controls of an electric drill is fraught with trouble. The engine will stall and the ship will stop. The advantage is that it is very easy to find spare parts for the drill.

Another significant point is that it is not intended to operate continuously. This is not very suitable for boat engines. Therefore, it is advisable to create a power reserve to avoid overheating of the homemade product.

We recommend reading: Popular Korean manufacturers of outboard motors

  1. You need to start from one hundred and fifty watts and more.
  2. In this case, it is realistic to choose a propeller with a diameter of one hundred and thirty millimeters.
  3. The total weight of the vessel is no more than three hundred kilograms.

The voltage of drills and screwdrivers can be different, as well as their batteries. But the capacity of the latter is not enough to control the boat. Then a car battery that produces twelve volts will do. It is better to choose a drill with the same voltage.

Of course, a battery of batteries for any voltage will save the situation. But the cost of such a device can be expensive.

Required components

To make homemade motors for boats from a drill, you need to assemble a set of accessories and tools:

Helpful information
1slats for mounting the engine
2when hanging on the transom, a mechanical part from an angle grinder will do
3a pipe with a diameter of twenty millimeters is suitable for making a rod, and a frame made of a twenty by twenty millimeter profile is suitable for installing a motor
4metal rod to create the shaft and sheet metal for the screw
5hand scissors for tin
6electric drill with drill bits
7angle grinder with cutting and sharpening discs
8self-tapping screws if there is wood in the device

If you need to quickly remove the propeller, it is advisable to make a lifting mechanism to control the motor in a vertical and horizontal position.

To create the mechanism, you need to equip the clamps with rings and pass a tube through them. This articulated device ensures the reliability of the steering wheel.

Gearbox and propeller

The rotation speed of the drill is slightly higher than that required to operate the propeller. The gearbox will adjust the difference.

  1. The upper gearbox is capable of reducing speed from one and a half thousand to three hundred. In this situation, a homemade motor will allow the boat to move smoothly.
  2. The lower gearbox is important for horizontal positioning of the propeller. If it is taken from an angle grinder, just clamp it in the screwdriver chuck.

To make a propeller, you need to select certain sections on a steel sheet. A square of two hundred by two hundred millimeters and a thickness of three is enough. Stainless steel is much more difficult to cut, but it is preferable and lasts longer. You can also use a blade from a household exhaust fan.

You need to make holes in the center of the sheet. They are necessary for the landing screw. The slits are made diagonally, leaving a circle of thirty millimeters in the center.

The blades should be round and equal. Each one must be rotated at a certain angle and direction of rotation so that there is no vibration of the screw.

A properly assembled electric motor will return a stream of water, but without vibration. If something goes wrong, a design made for a boat with your own hands can always be improved with the help of a larger angle of inclination of the blades.

We recommend reading: Why are Tohatsu 4-stroke outboard engines so in demand?

Before you make a motor for a boat, you need to understand how it will move with its help.

It is important to take into account the weight of the vessel with all things, engine power, current strength and operating voltage. The motor power for a rubber boat or PVC should be at least twenty percent greater than the load power

This advantage will be useful in case of force majeure.

It is advisable to measure the voltage under load and during idling using a special device.

What are homemade boat motors made from?

Some products will be suitable, even faulty ones, but on one condition that their motor is working. Even if you buy a new gas mower or screwdriver, it will turn out to be much cheaper than a new outboard motor; all that remains is to modify the product a little. The financial issue turns out to be the main one in solving this problem, otherwise every boat would already have a motor.

  1. To make a boat motor with an electric drive, you will have to purchase a screwdriver or a battery-powered electric drill. It is possible that someone has a damaged screwdriver or drill lying around in their barn or garage. It is preferable to use a screwdriver, since its output speed is not so high.
  • Naturally, those batteries that are installed on electrical appliances are not powerful enough to move around a body of water for a long time. In this case, a 12 V car battery is suitable. Naturally, devices must be purchased for the same operating voltage. The power of an electrical device of 300 W is enough for the boat to move around a pond with a load.
  • The problem of reducing the speed of the electrical appliance must also be solved. In this case, you will need a gearbox. This is especially true when using an electric drill.
  • You will also have to make or buy a drive shaft and propeller. The advantage of an electric boat motor is that it operates silently. In addition, repairing such a motor will cost much less than repairing a classic outboard motor.
  1. Gasoline engines are much more powerful, so they can significantly increase the fishing area. In addition, their power does not decrease, like with electric motors, and the battery has significant weight and takes up useful space. You can use power units from brush cutters, walk-behind tractors, chainsaws, etc. You should choose based on your financial capabilities, the size of the boat, as well as what device is available.
  • Trimmers are most suitable for such purposes, since they require minimal modifications. It is enough to replace the device where the fishing line is attached and install the propeller, and the motor is ready and can be used.
  • Other power devices require more serious modifications, since they require a gearbox, shaft and propeller. In addition, they need to be connected together.

On a note! Some fishermen use a motorized cultivator by removing the cutters and installing primitive rowing blades in their place.

In addition to making the motor, you should think about how to mount it on the boat. The fact is that not every boat has a transom and not every boat is suitable for installing a motor. It is especially difficult to install such a device on a rubber inflatable boat.

What work does the manufacturer have to do?

Throughout the entire process of manufacturing a boat power unit, it is important to adhere to the correct work algorithm. First of all, the manufacturer must carefully study the detailed drawings prepared in advance

In order to prevent critical errors during design, you need to indicate in them the dimensions of all parts used, as well as the methods of their initial fastening.

The operator's subsequent sequence of actions should consist of the following steps:

  1. Replacing the working parts of a chainsaw with a metal pipe with a propeller;
  2. Installing and checking the fasteners necessary to secure the screw;
  3. Connecting the gearbox shaft to the power unit from a chainsaw;
  4. Development of the required rotary unit;
  5. Adaptation of the gearbox shaft used to the propeller;
  6. Final assembly of equipment.

The working mechanisms used for assembly will need to be prepared:

  • a working and fully operational power unit from a chainsaw;
  • gearbox - can be removed from an old grinder;
  • propeller - you can take it ready-made or assemble it yourself;
  • transom - purchased separately;
  • connecting clamp.

Additionally, the manufacturer should have fasteners of various types and sizes at hand, as well as metal parts: pipes, angles, ties and spacers.

Boat mounts

The mounting location for the outboard motor is called the transom. This part must be durable and reliable. In order to correctly design the part, they carefully study the technical characteristics of the boat and the motor, since the transom creates additional load. The transom for an inflatable boat consists of:

The edges of waterproof plywood are treated with sandpaper. Loops for metal staples are installed on the plate. The fastening arcs are bent using a machine; you can do it manually. Eyes are made of plastic or bought in a store.

Source

Assembling the sawmill

When building houses and other structures from logs, it is often necessary to cut them into beams. A chainsaw sawmill allows you to do this as efficiently as possible with good cutting accuracy. At the same time, the instrument itself does not require any modifications. It is simply fixed in a frame made, for example, from metal corners or profile pipes. The processed logs are placed on guides. The entire structure is shown in the diagram below.

In a homemade sawmill, the log is not moved: a carriage with a saw moves, fixed at the required height (depending on the thickness of the lumber) with four screws. Due to the fact that the frame moves accurately, sawing occurs carefully and the cut is smooth. The created device (a version of it is shown in the photo below) also allows you to saw boards and prepare firewood without any problems.

Jet engine design

The main elements of such a mechanism, as in the classic version, are the internal combustion engine and the propeller, only the latter is located inside a long pipe laid along the hull of the boat. Of course, “pipe” is an oversimplified term. The correct name for this part of the engine is the water conduit, and it consists of the following components:

  • water intake: the front part through which water flows to the propeller;
  • straightening apparatus: thanks to this element, the rotational movement of the water flow twisted by a screw is transformed into a rectilinear one;
  • nozzle apparatus: the final part of the “pipe” from which water is thrown out.

Another important element of the water cannon is the reversible steering device, thanks to which the boat can change the direction of movement and also reverse.

Water jet engine design diagram

Screws (also called impellers or impellers) come in several types:

  • Axial: the simplest to manufacture, but they provide the lowest efficiency and, due to the pronounced cavitation effect, can only operate at low speeds.
  • Axial-diagonal: have higher efficiency and are designed for medium-speed engines;
  • Diagonal and screw: the most modern and extremely difficult to manufacture varieties, they are characterized by the highest efficiency and are capable of working with high-speed engines.

Among all the components of a water cannon, propellers are in first place in terms of manufacturing complexity. For this purpose, the method of precision casting followed by grinding is used.

You should not purchase a water cannon with an impeller whose blades are welded to the hub and do not form a single whole with it: such propellers often have an imbalance, which leads to their destruction at high speeds.

Gearbox and its influence on operation

The use of a gearbox for a boat motor allows you to change the direction of axial rotation. The gearbox changes the shaft rotation speed several times, which has a positive effect on the operating life of the engine. When equipping a gearbox with a boat motor, you should stick to the golden mean and not install a device with a large gear ratio. Failure to comply with this rule leads to excessive fuel consumption, low boat speed and engine overheating. The most reliable way to install a gearbox with the optimal gear ratio for a given engine is to test several different devices. If during operation there is no feeling of excessive load, which manifests itself in the impossibility of quickly accelerating to high speeds and the speed of the craft is quite high, then this gear ratio can be considered optimal for a given engine.

An average gear ratio that will work well with many internal combustion engines used as a boat motor is 1/5.

Electric motors can be used as propulsion for boats without a gearbox. The traction force of such devices is sufficient to operate stably in the mode of direct transmission of torque to the propeller. An excellent engineering solution is to use an electric motor underwater. With this arrangement, the screw is fixed directly to the motor shaft.

How to make a boat motor with your own hands from a trimmer?

To assemble a motor from a trimmer to a boat, the manufacturer will need to prepare the following equipment and materials:

  • household brush cutter;
  • clamp. If it is not there, then you can use any other mount to securely fix the motor on the boat;
  • a sheet of duralumin, the thickness of which should not be less than 2 mm;
  • welding machine;
  • set of fasteners;
  • set of screwdrivers and wrenches.

To assemble a homemade propeller, the manufacturer will need drawings. They must indicate the exact dimensions of the blades and the method of fixing them on the axis.


It must be remembered that the lower the power of the drive used and the weight of the boat, the smaller the blades should be. For example, for a boat weighing no more than 120 kg, a propeller with 10x3 cm blades is suitable.

After preparing the equipment and carefully studying the drawings, you can begin assembling the homemade product.

The work algorithm should look like this:

  1. First of all, the manufacturer will need to modify the bent shaft. First you need to remove the factory nut, which is placed in a reel of pre-wound fishing line. The nut itself is shaped like a small 2-centimeter tube with an internal thread. If necessary, it can be divided into 2 small full nuts. When dismantling fasteners, you must be extremely careful not to lose them. If this happens, then it will no longer be possible to find another suitable fastener;
  2. After removing the nut, you will need to remove the plastic cover located on the gas button. There are no roller bearings at the end of the stock curved rod. They are replaced by an ordinary bronze bushing, which is often called a plain bearing. It must be carefully removed. Before this, you will need to unscrew the nut, and also remove the stern tube and metal shafts from the tube;
  3. Then you need to move on to knocking out the plastic protector located on the flexible shaft. In the future, the steel pipe can be thrown away, since it will not be possible to level it with improvised means. It can be replaced with a duralumin tube of the same diameter. You will need to install a bronze bushing into it, which will need to be moved along the canvas using a hammer. Next, you need to take a plastic protector pre-cut to the diameter and install it on the pipe;
  4. The next step is to make the screw. To do this, you need to cut out the duralumin blades and sharpen their edges. After this, each blade will need to be bent upward by 1 cm so that the screw pitch is at least 10 cm. You can secure the finished device using a nut;
  5. Next, you need to install a bicycle speed switch on the outboard motor from the brush cutter, which will replace the standard plastic cover. After this, you will need to install a muffler that will divert engine exhaust away from the boat driver;
  6. To secure the outboard motor from a lawn mower, you need to use two sheets of plywood. After this, it remains to clamp the shaft using 4 screws. When transporting the outboard motor from the trimmer, the shaft can be removed.

After the homemade nozzle is ready, it will need to be run in. To do this, you need to prepare a fuel mixture of fresh gasoline and motor oil in a ratio of 40:1. After this, you will need to pour the prepared mixture into the standard tank of the boat engine, start it, and let it burn out 1 full tank of fuel at idle speed. After running in, the homemade boat motor from the trimmer will be completely ready for work.

Creation of an electric motor

As mentioned earlier, you need to start making an electric motor with your own hands by creating a lifting mechanism for the impeller. It will allow you to lift this element above the water. To create it, you need to weld a metal tube to pre-prepared clamps.

You must first attach a base to this tube (a frame shaped like a pyramid, with its smaller base pointing in the direction of the water). A frame is attached to a large base, and another tube is welded to the lower edge. A bearing is installed on the frame. The shaft must be passed through it and the tube welded at the bottom.

You can use a tube or wire as a shaft. However, the first option is more successful:

  • firstly, bearings can be attached to the tube (at both ends), which will reduce the friction force;
  • secondly, it is desirable that this shaft be thin but strong. In the case of wire, you will have to use a large diameter product.

After all actions are completed, you can move on to the next stage. The next step is to install the gearbox and propellers.

Gearbox/propeller

It is recommended to attach gearboxes to the sides of the shaft. It is advisable to first create them yourself, focusing on the parameters of the electric motor. However, this process can take a very long time. Therefore, you can buy a device or use gearboxes installed on an angle grinder.


Depending on the specific engine, one or two gearboxes may be needed. When choosing a device, you need to focus on one basic rule - it is desirable that the transmitting number be small. It is optimal if the gearbox is capable of reducing the speed by 5 times. This will ensure the normal running of the boat.

The lower gearbox is necessary for horizontal mounting of the screw. If you use a gearbox from a tool such as an angle grinder, it will be enough to clamp it in a drill chuck. Elements of other devices can also be used as a propeller. If there is none, you can make a homemade screw. To do this you need:

  1. Cut a square (the length of one side is thirty centimeters).
  2. Drill a hole in its center.
  3. Make slits diagonally (the distance between the slits should be at least five centimeters).
  4. The resulting blades must be given a rounded appearance. It is important that the size of the blades is the same, otherwise third-party vibrations may occur.

What can a boat motor be made from?

The motor can be made in various ways, the main thing is to choose a suitable base and additional parts. An engine from a trimmer or walk-behind tractor, as well as a screwdriver, can be used as a base. A boat motor made from a chainsaw has the best characteristics.

From the trimmer

The trimmer boat motor saves fuel and has a transparent tank. The propeller (homemade propeller) is made of duralumin. The propeller blades are bent up to 10 mm, the edges are carefully sharpened. It is put on in place of the trimmer head. To prevent the propeller blades from damaging the boat during operation, use a ring attachment. The motor shaft and propeller are connected by adapters. The starter is removed from the lawnmower. The motor from the trimmer is made according to a drawing prepared in advance.

From a screwdriver

If you use a cordless screwdriver, you will get a good homemade engine. For manufacturing, it is better to choose a device with a voltage of 12 V. The process of making an electric motor for a boat with your own hands using a screwdriver:

  1. The propeller must have a lifting mechanism, so it is attached to the engine transom and secured with frames and plates.
  2. Clamps are equipped with rings. A tube with a shaft is laid through them. The shaft is made of steel wire or rod.
  3. Bearings are pressed inside the tube. They will provide the steel shaft with easy sliding.
  4. To reduce the speed of the electric motor, install a gearbox from an angle grinder. The upper part of the shaft is clamped in the screwdriver chuck.
  5. The propeller is made of stainless steel, the thickness of the sheet is 2.5-3 mm.

From a walk-behind tractor

From a walk-behind tractor starter you can make a motor for an engine. To assemble a four-stroke model, a simple fuel system is used, but the water pump must be of high quality. The sternwood is removed from the old boat engine. The fuel pump is installed above the carburetor so that it does not come into contact with the rocker arm, and secured with clamps. The crankshaft is mounted above the top gear. A water pump is installed under the deadwood. If you install springs, the lower rod will work freely.

You will find many other interesting homemade products from scrap materials here.

Refinement of lawn mowers

The boat motor from the trimmer requires a little modification to get a workhorse for the watercraft. The advantage of gasoline trimmers is their low price and maintainability. Homemade motors for boats based on gas trimmers have a built-in tank, shaft and gearbox. You can look for a special conversion kit, which will contain a stainless steel propeller and drive, as well as a set of adapters for the trimmer shaft. Often there are kits with a clamp for installation on the transom, so there will be no problems with fastening to the boat. If you follow the included instructions, you can convert a boat motor from a lawn mower in 20-30 minutes.

More skills will be required from the angler if he decides to radically change the design of the trimmer. In this case, there is huge scope for imagination and ingenuity. One option involves making a vertical leg.

  1. To rotate the shaft 90 degrees relative to the engine, you will need a gearbox from an angle grinder.
  2. The existing trimmer tube must be shortened using a cutting machine. It is better to replace the bushings inside with bearings.
  1. A simple screw can be made from a strip of duralumin 10x30 cm, 2 mm thick. By attaching a stencil with a two-bladed screw to the workpiece, you need to make markings. You can cut the screw using a grinder and a chisel. The edges must be processed with a file. Place the plate on a flat surface and bend both blades to a height of 1 cm.
  1. A hole is drilled in the center to connect to the shaft. To prevent the blade from touching the watercraft's cylinder during rotation, it is better to make a ring attachment. The trimmer-based boat motor is ready, you can go to the pond.

What is an electric motor for a boat?

As the name suggests, unlike a fuel-powered boat motor, an electric motor runs on energy transferred to it from a power source. A rechargeable battery (AB) is used as such a source, so the second name for an electric motor is a rechargeable boat motor. At the same time, manufacturers produce equipment compatible with voltages of 12, 24 and 36 V, respectively, the higher this indicator, the greater the performance of the engine.

The design of electric boat motors is quite simple. The device is equipped with a control panel, tiller, connecting rod, motor, propeller and rotor. In this case, the structure is essentially divided into 2 parts: surface (tiller, control panel) and underwater (engine, propeller, rotor). And they are connected by a rod, the length of which is freely adjustable, which gives great advantages when moving and fishing in shallow water. Such a rod is made of impact-resistant metals, so that it is not afraid of collisions between the vessel and any obstacles.

The electric boat motor starts working immediately after pressing the switch once. Thus, the time required to start fuel units is significantly saved. Typically, an electric motor for boats has 4-5 speeds for forward movement and another 3 gears for reverse. In this case, the speeds are switched manually or in foot mode. This is an important factor, because, for example, fishermen need both free hands and full control of the vessel.

Thus, the design of electric motors gives them a number of advantages over fuel-powered devices. For example, an electric motor for an inflatable boat allows the vessel to move smoothly on bodies of water without scaring away the fish with the noisy operation of the engine. The same applies to plastic boats, rubber boats and other small vessels. In general, watercraft equipped with an outboard electric motor are used for:

  • trolling;
  • boat trips;
  • spinning fishing;
  • moving through bodies of water overgrown with vegetation;
  • steering and maneuverability in shallow water.

Such motors also perform well in terms of power characteristics. However, they are somewhat specific, so we will consider the speed indicators of electric motors separately.

Thrust and speed of a boat with an electric motor

Unlike fuel units, the power of electric motors on a boat is measured not in horsepower and kilowatts, but using a special characteristic - thrust. The term “thrust” refers to the maximum force that a given electric outboard motor is capable of developing during operation. Moreover, the size and rotation speed of the engine propeller, which does the main work, are of decisive importance here.

Thrust is measured based on calculations of the vessel's speed and water or wind resistance and is most often expressed in pounds (to convert to kg, multiply the pound indicator by 0.45). At the same time, the displacement and dimensions of the boat are directly related to the tractive effort. The more massive the craft, the more thrust the motor should have. Moreover, for calculations the max. boat weight, i.e. weight of the vessel + equipment + cargo + passengers.

But then a treacherous question arises for shipowners: if you put a powerful electric motor for a yacht on a small boat, will its speed increase? Unfortunately, savvy fans of high-speed travel will have to be disappointed: an increase in traction is by no means equivalent to an increase in speed. The thing is that a boat with an electric motor is partially submerged and kept afloat by the force of Archimedes. And according to the laws of physics, it is virtually impossible to develop high speed overcoming such dense water resistance. So the vessel will definitely not move above the initial speed of 7-15 km/h (depending on the dimensions).

DIY boat electric motor

At one time, when King Hammurami still lived, he argued that the time spent fishing is not included in the calculation of the total life time. This is also confirmed by many citizens who like to spend part of their free time fishing.

Typically, most anglers own a boat. Many boats, especially modern ones, are equipped with gasoline engines. And a boat without a motor, especially if you have to fish in the waters of a large lake, becomes a burden that requires enormous costs, effort and energy to move. And here you definitely need a motor: gasoline or electric - it doesn’t matter.

Still, special attention should be paid to the electric motor because:

  • electric ones do not require either oil or gasoline to operate, which means there are no exhaust gases, which does not harm the environment;
  • electric motors are smaller in size, lighter in weight and do not take up much space. This is especially true if you have to fish far away, and every kilogram of excess weight is always felt;
  • they are much more economically profitable than their gasoline counterparts;
  • modern designs are assembled using modern parts developed using modern technologies, therefore they have maximum power with minimal weight.

But these statements only apply if the boat owner already has an electric motor and has experienced such benefits to the fullest. But what to do if it is not there? This means you need to do it yourself.

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