marine propulsion

5 Articles

China’s Nuclear-Powered Containership: A Fluke Or The Future Of Shipping?

December 26, 2023 by 73 Comments

Since China State Shipbuilding Corporation (CSSC) unveiled its KUN-24AP containership at the Marintec China Expo in Shanghai in early December of 2023, the internet has been abuzz about it. Not just because it’s the world’s largest container ship at a massive 24,000 TEU, but primarily because of the power source that will power this behemoth: a molten salt reactor of Chinese design that is said to use a thorium fuel cycle. Not only would this provide the immense amount of electrical power needed to propel the ship, it would eliminate harmful emissions and allow the ship to travel much faster than other containerships.

Meanwhile the Norwegian classification society, DNV, has already issued an approval-in-principle to CSSC Jiangnan Shipbuilding shipyard, which would be a clear sign that we may see the first of this kind of ship being launched. Although the shipping industry is currently struggling with falling demand and too many conventionally-powered ships that it had built when demand surged in 2020, this kind of new container ship might be just the game changer it needs to meet today’s economic reality.

That said, although a lot about the KUN-24AP is not public information, we can glean some information about the molten salt reactor design that will be used, along with how this fits into the whole picture of nuclear marine propulsion.

Continue reading “China’s Nuclear-Powered Containership: A Fluke Or The Future Of Shipping?” →

A pinwheel sits in an aquarium to simulate an offshore wind turbine. Bubbles come up from the "seabed" to encircle it to demonstrate a bubble curtain with an image of a sound waveform overlaid with the video to show the sound confined to the area within the bubble curtain.

Keeping The Noise Down Under The Sea

May 23, 2023 by 13 Comments

Since sound is the primary sense used by most ocean life, disruptions to the natural noise levels in the ocean from human activities can be particularly problematic for marine life. [DW Planet A] has a video describing some of the ways we can mitigate these disruptions to our friends under the sea.

Being noisy neighbors isn’t just a problem for whales but for everything down to the plankton at the base of the food web. Underwater construction like offshore wind installations get flak for being noisy, but technologies like bubble curtains can reduce noise output by up to 90% to the surrounding waters while still getting those nice low carbon energy benefits that prevent further ocean acidification and warming. Continue reading “Keeping The Noise Down Under The Sea” →

Simple Propulsion For The Lazy Paddle Boarder

August 1, 2022 by 14 Comments

One of the downsides to healthy outdoor activities is all the exercise. Who would want to do that if you can build something to do the hard work for you? That seems to be the theme of [Bitluni]’s latest build, a simple (and hacky) propulsion system for a stand-up paddleboard.

After acquiring an inflatable stand-up paddleboard and trying it out a few times, [Bitluni] decided to skip the “stand up” and “paddle” parts. He designed and printed a very simple propeller, which he intended to power with a brushless motor and speed controller. In the process of drilling out the prop to fit the shaft, he realized he was overcomplicating things. So he decided to just use his battery-powered drill instead. For the shaft tube, he modified an old crutch by drilling a hole in the handle for the shaft and adding a duct with a bearing on the other end. He also attached a carabiner to the handle to fix it to the paddleboard.

A test at a lake showed that the propulsion system performed relatively well for a proof of concept but had some flaws. To submerge it properly, [Bitluni] had to sit on the rear of the paddleboard facing backward. If it was too close to the surface, it would suck air and lose thrust, or spray him and his drill with water. Of course, there is also the real risk of drowning his drill in the process.

Projects don’t need to be complex to be enjoyable, and you can often learn more by quickly creating a proof of concept instead of taking forever to come up with the “perfect” design.

If you want to see some more advanced water-borne projects, check out the waterjet-powered electric surfboards built by [RCLifeOn] and [Andrew W].

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Open Source Autopilot For Cheap Trolling Motors

September 24, 2021 by 14 Comments

Quiet electric trolling motors are great for gliding into your favorite fishing spot but require constant correction if wind and water currents are at play. As an alternative to expensive commercial GPS-guided trolling motors, [AlexAsplund] created Vanchor, an open source system for adding autopilot to a cheap trolling motor.

To autonomously control an off-the-shelf trolling motor, [Alex] designed a 3D printed steering unit powered by a stepper motor to attach to the original transom mount over the motor’s vertical shaft. A collar screwed to the shaft locks the motor into the steering unit when the motor is lowered. The main controller is a Raspberry Pi, which hosts a WiFi hotspot and web server for control and configuration using a smartphone. Using navigation data from an e-compass sensor and a marine GPS chart plotter, it can hold position, travel in a specified direction, or follow a defined route. [Alex] is also planning to add the option of using a GPS module instead of a commercial plotter.

For an estimated total of $300, including the motor, this seems like a viable alternative to commercial systems. Of course, it might be possible to add even more features by integrating the open source ArduRover autopilot, as we’ve seen [rctestflight] do on multiple autonomous vessels. You can also build your own open source chart plotter using OpenCPN, which rivals commercial offerings.

Ask Hackaday: What Are Magnetic Gears (Good For)?

August 15, 2016 by 51 Comments

Magnetic gears are surprisingly unknown and used only in a few niche applications. Yet, their popularity is on the rise, and they are one of the slickest solutions for transmitting mechanical energy, converting rotational torque and RPM. Sooner or later, you’re bound to stumble upon them somewhere, so let’s check them out to see what they are and what they are good for.

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