XRP Boat Mod

Update

The XRP Boat Mod is my very first XRP mod of many that did follow by now. So I decided it deserves a bit of TLC and improved it with everything I learned on my journey.

The original files and instructions are available as zip archive in case you need spare parts. For everyone else I would recommend to go with v1.1. 

Changes in v1.1

• Integrated a spacer into the water wheel to reduce friction with the mount
• Shaft refinement of the water wheel
• Improved the Safety Ring System
• Completely reworked the axis, improved mesh, reduced length
• Merged the transmission disc with the shaft for easier printing
• Length of the Bottle Holder slightly increased
• Angle of the Bottle Holder slightly decreased
• Rounded corners of the Bottle Holder
• Rounded corners of the Wheel Mount
• Rounded corners of the Rescue Arm
• Wheel Mount has been made slimmer
• Updated tolerance test

General:

Probably needless to say, but water and electronics are no friends! Be careful, protect your sensors with enclosures like my XRP Rain Guard, plastic bags, etc from water, spills and splash. All rail mounts have slots for zip ties, so you can attach everything safely to the frame and don't lose parts.

Additional Equipment Needed:

• 2x Empty Bottles
• 2x Rubber Bands
• Some Zip Ties (max. width 4.5mm)

Optional:

• A freezer
• Some string
• XRP Rain Guard or XRP Rainguard v2 from my other models to add some splash protection
• If you don't already own a XRP

Print list:

• 4x Bottle Holders
• 2x Water Wheel Mounts
• 2x Water Wheels
• 2x Axis with Transmission Disc
• 2x Safety Rings

Optional Prints:

• 1x Safety Ring Tool
• 1x Caster Remover Tool
• 1x Rescue Arm
• 1x Tolerance Test
• 2x Wheels from the officially provided XRP files
• 1x Name Tag Pole
• 1x Name Tag Flag (add your name in your slicer)
• 1x XRP Rain Cover
  • 2x Rain Cover Hinges

Print Settings:

I didn't use any special settings for printing. I included some files so you can test your printers tolerances ahead to see if everything fits well together for you. The models in the stl files do have my recommended print orientation and it's the way I did print them regarding print quality, layer strength and required support. Sometimes you need to make a compromis, like with the shaft, the strength is not optimal for this part, but sufficient for the forces it has to take. You might only need to handle it a bit more careful, but it will not affect the performance in this build. 

If you want to fine tune it you can use modifier blocks to slow down sensitive areas like the safety ring slot or any other overhang as well as use variable layer height to increase details. 

Also I would print the axis with a relatively high infill density like 40% or increase teh wall count. The axis are mainly walls anyway..

You might need to adjust the seam gap, or x-y hole compensation. You want a good tight fit for the water wheels where the axis needs to be able to spin freely inside the water wheel mount. A to big seam on both prints might cause some friction. My prefered method is seam scarf joint or you might prefer to use a random seam position rather than aligning them for parts where you want low friction. But don't worry too much but I prefer fine tuning over sanding and drilling.

Instruction:

Prepare the Bottles

Pick the right bottles, I would recommend something between 1.5L and 2L. If possible with a quite straight body. Don't forget that the water wheels need to be in contact with the water and the drive shouldn't touch the bottles. How deep it will sit in the water can also be adjusted by adding liquid into the bottles. Otherwise the bottle holders are universally designed to fit all sort of bottles. Be sure they're firmly closed.

Optional: The bottles can also be painted. Either paint them from the outside with e.g. a spraycan or just fill in some paint and swirl it around. But don't use spray cans on the inside, they will not work reasonably due to a bottle being a closed container. Also check if your paint is compatible with the bottle materials first. For e.g. PET bottles this shouldn't be a problem. 

Optional: Open the empty bottle and put it into the freezer for about 10 minutes. After the time has passed, open the freezer and close the bottle tightly with the lid. Air is more dense when cold. As soon as the bottle warms up the air will expand and give it a nice full touch. This is mainly for better optic, it will have little impact on performance.

Bottle Holders

Mount all bottle holders to the side rail system. There's no orientation. I would recommend to put them to the very edge of the XRP. But a good contact with your bottle is priority, so this might be different for you. Once the bottle holders are mounted put them on your bottles and fix them with some zip ties so the bottle holders got a firm grip. Keep in mind those rails are mainly intended to hold like a 10g sensor.

Drivetrain

There's also a picture that might help you visualizing what you got to do. Once you have to put the axis thru the mount from the left and once from the right, so you got 2 mirrored versions! Put the axis thru the water wheel mounts and the water wheel on the other side. Use the safety rings along with the safety tool to ensure everything stays in position. Mount the water wheel mounts on the rear rail, aim for a good alignment between the wheels of the XRP and the transmission disk. The safety rings can also easily be removed with the other side of the safety ring tool if needed.

Connect the drivetrain

Fully read this paragraph before continuing!

Either remove the o-rings from your wheels or print another set of wheels from the officially provided files. Now connect the rubber band with the transmission disk and the wheels that are mounted to the motors. In order for a working transmission you need a tight fit. You can ensure it's tight by just spinning either the wheels at your motor or the water wheel. But disconnect your motors wiring first! Spinning your motor will cause reverse voltage that might cause damage to connected hardware!

I did use ordinary office rubber bands and they worked flawless. They have been 8cm (like as a ring, if you would cut them they'd be 16cm long).

Optional

Rescue Arm

If you want to play it safe and not get afloat on a lake you can add the rescue arm anywhere on the rail with a string attached so you could pull it back. this might be good for the first test ride. An empty battery, some programming issues or a stream might end the ride otherwise rather fast. In that case you could manually pull it out of a lake. It can also be used as an anchor.

Rain Cover

Optionally mount the rain cover clips on the rear side of your rails, connect them with the hinges of your rain cover. Now you can open and close the lid as desired. But also be aware of water from the bottom side. Also the print orientation for the clips on the rain cover are not ideal, so they will be fragile, handle them with care.

Name Tag

Use the caster remover tool to remove the caster, put in your name tag pole and your name tag flag. The flag can be modified in your slicer. E.g. right mouse button and either add them as part text or as negative text. Add your name, once you placed it and you're happy, select both parts, right mouse button and select mesh boolean.

Recommended - Zip down all parts

If you don't want to lose parts or play submarine, all the provided XPR attachments do have holes for zip ties so you can connect everything safely to the frame. There might be quite some tension on the drive, you could hit a rock etc. Don't forget that the rails are mainly designed for like 10g sensors and not for parts that have to withstand quite some force.

We're done.

Have fun exploring the next lake or river, share some images of your builds and ride. :)