Hacking A Fuel Sensor Into A Portable Tank, Literally

Regular readers of Hackaday will know that the projects we feature are generally of the high-tech variety. Microcontrollers, 3D printed parts, embedded Linux, lots of wires, that sort of thing. But that’s not to say we don’t appreciate the somewhat more visceral builds out there; after all, hacking is about creative problem solving and thinking outside the box, and none of that is limited to how complex the fix actually is.

Take for example this quick hack that [R. Preston McAfee] recently sent our way. Looking for a way to check how much fuel was left in his outboard motor’s small portable gas tank without crawling back to look at it, he decided to rig it up with a sending unit. While they’re technically designed for larger tanks which are permanently installed into a boat’s hull, he reasoned there was nothing about the float sensor that would keep it from working in his case so long as it could be safely mounted.

To that end, [Preston] started by cutting a 38 mm (1.5″) hole in the thickest part of the tank, and sanded the area around the opening to smooth things out. He then measured the depth of the tank at that point, and ordered an appropriately sized float sensor. He drilled out the holes for the five mounting bolts, and inserted them through the larger whole so their heads would be inside the tank. By holding the exposed threads with a pair of vice grips he was able to crank the nuts down on each bolt to form a tight seal to the gasket, though it should be noted that the resulting damage to the threads will likely make it difficult to remove the nuts in the future.

Admittedly this is a pretty simple fix, but it’s well thought-out and we appreciate the effort [Preston] put in to documenting the whole process. We’ve certainly covered more elaborate ways of seeing what’s left in the tank, but just because a solution is flashier doesn’t mean it’s necessarily any better.

Old Boat Becomes Toasty Floating Sauna

A sauna is a great place to feel warm and toasty and refreshed, but few of us have one at home. [Linus Strothmann] decided to build his own, using an old boat as the perfect base for his steamy build.

Finding the right boat was the first challenge; the vessel should be big enough to fully house the intended number of occupants, and be able to withstand sitting outside in the weather year-round. If it’s to be used in a place where it gets icy in winter, it’s best to go with a steel-hulled vessel.  [Linus] found a steel-hulled boat just under 8 m in length for less than 1000 Euros, and set to work on his project.

The boat was stripped out, and given high-quality glass windows capable of resisting the steam and high temperatures inside. A stove was installed for producing steam, and the boat-sauna was designed with multiple entries and exits for safety reasons. Insulation was also fitted to help keep heat in.

The result is a floating sauna that is an absolute pleasure to use in the winter months. Floating out on the lake, one can take in a steam, have a quick dip in the icy water, and then return to warm back up inside. [Linus] hopes to soon fit a small motor in order to allow the vessel to head out to the middle of the lake for an even better view during a steam session.

It’s not the first mobile sauna we’ve seen; a trailer-based design graced these pages last year. If you’re working on your own hot and steamy build, though, do share your work with us promptly!

Trying And (Mostly) Failing To 3D Print A Hydrofoil

[Sam Barker] had a boring dingy that he wanted to spice up a bit, so he resolved to 3D print a hydrofoil wing for it so that it could fly across the water. (Video, embedded below.)

With a large wing designed and sliced into several pieces, and a total print time of 200 hours, [Sam] was ready to glue the foil wing together when he realized his scale was way off and the wings were far too large for his boat. With some hacking, [Sam] was able to use a single wing across the bottom of the ship. [Tom Stanton] came over to help with fiberglassing, and they were ready for a test.

As you might have guessed from the title, the test wasn’t particularly successful. Swapping the engine on the boat for a more potent motor gave the lift he needed in the front, but without a back foil, it was a wheelie rather than what [Sam] hoped for. Back at home, they printed a second wing and went back for a second test. The boat would start to lift out the water, but the shaft of the engine lifted out of the water, sending him back down. Unfortunately, a downpour cut the test short.

Not to be defeated entirely, [Sam] connected it to a much larger boat once the weather cleared and pulled his dingy along behind. To [Sam’s] credit, they did get some solid foiling, and the ship did lift out of the water until the wings sheared off from the stress. All in all, an entertaining story of engineering while racing against the weather.

We admire [Sam’s] ambition, and if you’re thinking about building a whole hydrofoil, we suggest starting with a smaller RC model and scaling up from there.

Waterjet-Powered Speedboat For Fun And Research

There are a lot of cliches about the perils of boat ownership. “The best two days of a boat owner’s life are the day they buy their boat, and the day they sell it” immediately springs to mind, for example, but there is a loophole to an otherwise bottomless pit of boat ownership: building a small robotic speedboat instead of owning the full-size version. Not only will you save loads of money and frustration, but you can also use your 3D-printed boat as a base for educational and research projects.

The autonomous speedboats have a modular hull design to make them easy to 3D print, and they use a waterjet for propulsion which improves their reliability in shallow waters and reduces the likelihood that they will get tangled on anything or injure an animal or human. The platform is specifically designed to be able to house any of a wide array of sensors to enable people to easily perform automated tasks in bodies of water such as monitoring for pollution, search-and-rescue, and various inspections. A monohull version with a single jet was prototyped first, but eventually a twin-hulled catamaran with two jets was produced which improved the stability and reliability of the platform.

All of the files needed to get started with your own autonomous (or remote-controlled) speedboat are available on the project’s page. The creators are hopeful that this platform suits a wide variety of needs and that a community is created of technology enthusiasts, engineers, and researchers working on autonomous marine robotic platforms. If you’d prefer to ditch the motor, though, we have seen a few autonomous sailboats used for research purposes as well.

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Automate The Freight: Autonomous Ships Look For Their Niche

It is by no means an overstatement to say that life as we know it would grind to a halt without cargo ships. If any doubt remained about that fact, the last year and a half of supply chain woes put that to bed; we all now know just how much of the stuff we need — and sadly, a lot of the stuff we don’t need but still think we do — comes to us by way of one or more ocean crossings, on vessels specialized to carry everything from shipping containers to bulk liquid and solid cargo.

While the large and complex vessels that form the backbone of these globe-spanning supply chains are marvelous engineering achievements, they’re still utterly dependent on their crews to make them run efficiently. So it’s not at all surprising to learn that some shipping lines are working on ways to completely automate their cargo ships, to reduce their exposure to the need for human labor. On paper, it seems like a great idea — unless you’re a seafarer, of course. But is it a realistic scenario? Will shipping companies realize the savings that they apparently hope for by having fleets of unmanned cargo vessels plying the world’s oceans? Is this the right way to automate the freight?

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The World’s First Autonomous Electric Cargo Ship Is Due To Set Sail

Maritime shipping is big business, with gigantic container ships responsible for moving the vast majority of the world’s goods from point A to points B, C and D. Of course, there’s a significant environmental impact from all this activity, something ill befitting the cleaner, cooler world we hope the future will be. Thus, alternatives to the fossil fuel burning ships of old must be found. To that end, Norwegian company Yara International has developed a zero-emission ship by the name of Yara Birkeland, which aims to show the way forward into a world of electric, autonomous sea transport. 

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Homebrew Sounder Maps The Depths In Depth

For those who like to muck around in boats, there’s enough to worry about without wondering if you’re going to run aground. And there’s really no way to know that other than to work from charts that show you exactly what lies beneath. But what does one do for places where no such charts exist? Easy — make your own homebrew water depth logger.

Thankfully, gone are the days when an able seaman would manually deploy the sounding line and call out the depth to the bottom. [Neumi]’s sounding rig uses an off-the-shelf sonar depth sounder, one with NMEA, or National Marine Electronic Association, output. Combined with a GPS module and an Arduino with an SD card, the rig can keep track not only of how much water is below it, but exactly where the measurement point is. The whole thing is rigged up to an inflatable dinghy which lets it slowly ply the confines of a small marina, working in and out of the nooks and crannies. A bit of Python and matplotlib stitches that data together into a bathymetric map of the harbor, with pretty fine detail. The chart also takes the tides into account, as the water level varies quite a bit over the four hours it takes to gather all the data. See it in action in the video after the hop.

There’s something cool about revealing the mysteries of the deep, even if they’re not that deep. Want to go a little deeper? We’ve seen that before too.

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