Building a Boat for Mij Little Son

About: Hello:.. I am Erik van der Lelie, Born at 27-03-1964, in Huissen, nearby Arnhem. I have one Son, and now I live in Arnhem, in The Netherlands The card (foto in mij profile) I built as a prototype for a pro...

I am building a boat for mij son, it's a challence for me to do so, I wanted to know if I could do it, I also prommissed mij son this, so, I have to do so,
About the boat, it's electrical powered bij 6 :12 volts batteries, 35 Ah. The power is regulated bij two switches, I built mijself, becouse of the relatively high current, the DC-motor consumes, and becouse of the relyabillity of the switches. The motor asks for 35 Amps continiusly, if schwitched to 24 volts. By schwitching the batterys from parrallel to serial, I can chose to go half, and full power.(I did'nt chose for an electronical regulation, becouse of the losts of energy it comes with, Transistors and Hexfets always get hot, I could schwitch a lot of them in paralel, and regulate with a pulse width regulator, but I don't like the sound of that type of regulator, The motor would function as a speaker to the frequenty of the pulsing power) The motor is built to work on 36 volts in principal, but for safety reasons, I chose not to use that option. With a polarity reverse schwitch, I can also breake, if nessessery , or go backwards, You must excuse me, if i dont type the words correctly, but I am a Dutchman, and Englisch is not mij strongest side, so. But I trye. The boat is built from wood, Concrete- multiplex, and one-dimensional bendable tripex. Most of the rond cilindrical parts for the clutch and the motor I built mijself on mij hobbyclub. and at home. Also the stearingwheel that I welded and it was the first time for me to weld copper. the seats are made from wood, foam, and leather, that I took from a leather sofa, that people had thrown away. The roof I made also on mij sewingmachine, That I learned how to do from mij mother, bij watching her in mij childhood.

I hope you enjoy watching the foto's and videos, And I also wish you all lots of succes in inventing and building your own objects.
I built also a testing installation, to test if a steal cable with a diametre of 3 mm, could be used as a stearingcable inside a 12 mm copper tube, that I already have buildt inside the boat, It runned for two days an had made 240,000 cycles trough a little piece of copper tube, with an angle in it of approximately 90 derees. And loaded with a force, about 50 Newton produced by a strong elastical cord.
I lubricated with ballbearing grease. The wear out was minimal, after 240,000 cycles, so I was sattiscfied, (Afer all it's mij son, and all about safety, and reliability) I kept the seats as low as possible, and the batteries will be placed under the front seats. in order to keep the gravitypoint as deep as possible. This for stability.
To get a higher rendement I deliberately used this model boat, becouse it lifts it self on to the water, so you don't create waves to your sides, That would be a lost of energy, I calculated that the boat with 4 people inside, and batteries included would go about 14, or 15 cm uner the water line level with its bottom , and it would take about 1600 kg to go under, that's good enough for me. In totality it would take 1800 kg, but I already incalculated the weight of the boat itself. motor and batteries included. The window, roof and back part of the boat are removable, to save space, and to get it out of mij livingroom. On it's side it's 66 cm in height, and mij door is 78 cm wide.
In the fotos you also see the test with motor and axes and propellor at full power, (36volts) The motor was not placed in the boat yet.

To wire up the motor I used 7x 1.5 square mm copper wire, I stripped from it's insulation, In total 100 meter. Next I had 14 meter of 10.5 sqare mm Copper wire, as I twisted them together. Then I measured and cutted the cables to length, Then i insulated the new cables with flexible, pvc aquarium airtube. Then I welded copper plates, I made from 15 mm copper tube, to the ends of the cable. First I flattened the little pieces of copper tube a little bit, then, I putted in the copper cable, and flattened the copper tube completely with a flat hammer. I welded the cable in the copper tube using a butane burner, With lead-tin (?) weldingstuff, Then I drilled a hole into the copper plates on the ends of the cable. I marked the ends of the cable with pvc tape (On the pvc airtube), so i could connect the cables in a later stadium correctly. I made 6 cables: 2 for the motor, and 4 for the batteries. There is also a big battery for the accesoiries, such as lights, the radio, and the CB-transmitter, I am going to build in the boat. There is also a a 12 volts connection for a car lightener, so I can connect other accesoiries that use 12 volts. In the pictures you see a test-cable, I made to see what it would look like, Here it is painted 3x whith green paint to insulate it,

It was worth all the work, becouse 10.5 square mm cable to buy is very expensive. (80 Euro), and now it costed me about 30 Euro.

In the reply somebody alsked me especialy about the drivetrain, so I uploaded some foto's from that to.

The propellor I have made from steal (3 mm), That was quite difficult, because I had to get it perfectly semetrical. And in balance, so it would not vibrate to much. The center of the propellor is made from 60 mm solide steal, The diameter of the axes is 25 mm. The propellor is mounted to the axes with an 8 mm steal bolt, that as an 6-hole in the center, so it disappears completely into the steal center of the propellor.. It also goes in the axes for about 20 mm, In orde to get the propellor as symetrical as possible, I temporarely welded the blades together ans sanded them in shape, using a sanderbelt. Then i cutted them lose, and i had 3 exact the same blades.
The ballbearings, I took from an old washingmachine, People had thrown away.

The ruther i have made from 3 mm steal plate . It is placed around the propellor.

An advantage of this type of stearing is, that when you are laying still in the water, and you want to start , you can stear emediately,
Without having any speed, In this way the stearing is very directly, and you can make sharper cuves if you want to.

The water-channels here have lots of cuves of 90 degees, and are not very wide.

I also did it for safety, It's not so easy to touch the rotating propellor in this way, So there is less chance of injury.

There is also less chance of damaging the propellor, if you hit something in the water.

The stearing now is done bij 8 mm polyester cord in a copper tube, of 12 mm, but i am going to use a 5 mm steal cable, because the polyester rope is to flexible, which makes the stearing to indirectly. The rope also sticks to much inside the curves of the copper tubes, by adhesif forces. I'll lubricate the steal cable (which has a very thin layer of transparant pvc around it) with Teflon-grease. That mostly reduces the friction, and is the less adhesif. (so told by a friend) If that does'nt work properly, I'll remove the thin transparant pvc-layer from the steal cable to reduce the adhesif forces.

I added 2 drawings of the schematics of the paralel serial, and the polarity reverse schwitch, to illustrate, (the paralel serial schematic also has a zero-position, 0 volts = off)

Right now I am building a transportation device so I can walk with the boat to the water nearby.


!!!! ATTENTION !!!! !!!!SAFETY!!!!

Please be carefull, in using high currents, do prevent shortcut, to not create a fire !

Make sure you have the right cables!

And prefer to use a fuse at all times in serial between power and load ! (I used one of 100 Amps)

Pay special attention to insulation between cables!

Use the right schwitches so the contacts can not melt together. (not to light)

Polarity reverse should not be used to reverse polarity of electronical equipment such as radios, computers and other devices wich need to be connected only the proper way. I use it only to reverse the rotation-direction of the DC-motor. Electronical divices can be seriously damaged by reversing polarity.


Friendly greetings: Erik van der Lelie. The Netherlands

And i wish you all lotst of succes in building and inventing your own creations.

You may also watch more of my creations at Youtube, My users-name there is: hendrik6172

P.S. The boat is not quite ready to fully test in the water, there are still few things to work at.



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    17 Discussions


    1 year ago

    Hi Erik,
    I am very interested to know how you place the propeller barrel in order to avoid leaking. Did you place it above water level?

    warm regards from Indonesia!


    5 years ago on Introduction

    Beste Erik,

    Heb je soms plannen van die boot? Ikzelf heb men twee goeie vriendjes van 7 & 8 jaar oud (kleine broer en zus van men vriendin) beloofd een nieuwe boot te maken voor hen. Ze hebben een polyester geval dat verduurd is en nuja... it's a sinking boat :D
    Heb je de motor zelf omgebouwd naar een die bruikbaar is voor een boot? Lijkt me anders wel mooi draaiwerk zo'n passing.

    Alvast erg bedankt!



    5 years ago on Introduction

    That is really cool check out my boat on how to make a coroplast boat


    7 years ago on Introduction

    real nice build, be a real interesting "ible" if there were more pics and instructions, particularly the drivetrain

    1 reply

    Thank you for replying, I am still working on my profile, and uploading fotos, and i placed more fotos today. And you can also view on Youtube, some videos of me, There mij users name is hendrik 6172 .

    Greetings; Erik.


    7 years ago on Introduction

    Cool just saying your english is good (but in engish ij does't exist)
    dutch: i is I ,ij is y laar goed gedaan hoor ;-)

    1 reply

    Thank you, I have'not posted More pictures, but I am new on this site And I must get used to workin with it, You also make nice things, I see. Greetings Erik.