Concrete Boat Cements Its Way To High Speeds

Steel is scarce. Wood is not an option. And you need a boat now. These wartime circumstances drove innovation in all kinds of crazy directions, and one somewhat less crazy direction — concrete boats. As [Peter Sripol] demonstrates in the video below the break, making an RC concrete boat isn’t hard. Making a fast one on the other hand is. But that didn’t stop him from trying, and we think the effort deserves a look.

Starting with a basic displacement style hull, [Peter] and his cohorts experimented with a simple RC boat that worked, but could only move at slow speeds. They turned things up a notch or two and instead modeled their concrete boat after an RC speedboat hull that they had on hand.

The construction methods left a lot to be desired though, and they even tried various wire meshes as rebar, but they proved too heavy. Eventually though, they got a working hull, and had some fun with it. Rather than try to make the hull watertight with a rudder and propeller, they opted for a ducted fan and an airboat style rudder to make what they call the “world’s fastest concrete boat”.

Whether it’s the fastest or not is unconfirmed, but it is fast and actually gets on step fairly nicely. We applaud the exploration of alternative materials and the experimentation with different build methods. If building things with concrete floats your boat, then be sure to check out this concrete pinhole camera.

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Neat Little Airboat Built From Old Drone Parts

Multirotor drones tend to need quality and well-matched parts in order to stay balanced and in the air. However, crash enough drones and you might find you’ve got plenty of mistmatched bits and pieces lying around. In just this vein, [Jason Suter] decided to raid his junk box and built himself a little FPV airboat using spare parts.

The airboat consists of a 3D printed hull, paired with a separate power module. The power module houses the flight controller, and mounts twin motors on the rear. Fitted with three-blade props, they propel the boat and allow it to be steered with differential thrust instead of a rudder. It’s then fitted with a camera to allow it to be piloted with an FPV headset.

Handling still isn’t perfect, and water on the FPV antenna causes some issues with video transmission. However, it’s a fun project that makes good use of old parts. Of course, if you’re having vibration problems with your own FPV projects, consider building a vibration-absorbing mount. Video after the break.
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Electric Airboat For Getting You Across Thin Ice

Even with all the technological progress civilization has made, weather and seasons still have a major impact on our lives. [John de Hosson] owns a cabin on an island in a Swedish lake, and reaching it involves crossing 500 m of water. In summer this is done with a conventional boat, and in winter they can simply walk across the thick ice, but neither of these is an option on thin ice in the spring or fall. To solve this [John] built an electric airboat, and it looks like a ton of fun in the video after the break

The construction is simple but functional. A 3.3 m flat-bottomed aluminum boat has used a base, and an aluminum frame was bolted on for the motor and propeller. The motor is an 18 kW brushless motor, with a 160 cm/63-inch carbon fiber propeller. Power comes via a 1000 A ESC from a 100V 3.7 kWh Lipo pack mounted in a plastic box. Steering is very similar to a normal airboat, with a pair of air rudders behind the propeller, controlled by a steering lever next to the driver’s seat. The throttle is an RC controller with the receiver wired to the ESC.

Performance is excellent, and it accelerates well on ice and slush, even with two people on board. [John] still plans to make several improvements, with a full safety cage around the propeller being at the top of the list. He is also concerned that it will capsize on the water with the narrow hull, so a wider hull is planned. [John] has already bought a large steering servo to allow full remote control for moving cargo, with the addition of an FPV system. We would also add an emergency kill switch and waterproofing for the electronics to the list of upgrades. It looks as though the battery box is already removable, which is perfect for getting it out of the cold when not in use.

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Foam Airboat Is Cheap RC Fun

Archer fans and residents of Louisiana will already be familiar with the concept of the airboat. Put a powerful engine running an aircraft prop on a flat-bottomed hull, and you’ve got an excellent way to traverse the marshes of the American South. While a fully-fledged airboat might run you the best part of $100,000, this no-frills radio-controlled version is great fun at a much lower price.

The hull is built on a sheet of foam, which is cheap, readily available, and suitably buoyant for the task. It’s then kitted out with a brushless motor to run the prop and a servo to control the rudder. Lace it up with a radio receiver and speed controller and you’re good to go.

The build could readily be completed in well under a couple of hours, and is a great one to tackle with kids due to its mechanical simplicity. There’s room for extra creativity too – you can always substitute a watermelon if you’re feeling peckish. Video after the break. Continue reading “Foam Airboat Is Cheap RC Fun”