J. Adam Fenster / University of Rochester
Multiple unsinkable metal tubes interconnected in the shape of a raft could be the basis for the ships, buoys and floating platforms of the future.
A team of engineers created metal tubes that don’t sink, even when riddled with holes, bringing us closer to one day having truly unsinkable ships.
More than 100 years after the catastrophe of the mythical, allegedly “unsinkable” ship, the idea of unsinkable ships continues to drive engineering research.
A team of scientists at the University of Rochester has now taken a significant step toward that goal, with a method that makes common metal tubes effectively unsinkable.
These tubes stay afloat water regardless of the time they remain submerged or the physical damage they suffer.
The investigation was led by Chunlei Guoprofessor of optics and physics and senior researcher at the University of Rochester, and featured in a published Tuesday in the magazine Advanced Functional Materials.
The team approach involves Carefully engrave the inner surface of aluminum tubes to create microscopic and nanometer-scale cavities. This textured surface becomes super-hydrophobicwhich means that strongly repels water and stays dry.
When one of the treated tubes is submerged, the repellent interior of water traps a stable pocket of air inside. This layer of air prevents water from filling the tube and causing it to sink.
The process replicates strategies found in natureas with the bell spider (Argyroneta aquatica), which transports air bubbles underwater, or from fire ants (Solenopsis invicta), which connect with each other to form floating rafts using their water resistant bodies.
“A very important factor was that we added a divider to the middle of the tube so that, even if you push it vertically into the water, the air bubble remains trapped inside and the tube maintains its ability to float”, explains Guo.
Guo’s team had demonstrated floating devices for the first time super-hydrophobic in 2019, using two water-repellent discs sealed together to create buoyancy.
Although effective, this previous conception had limitations. At extreme angles, the disks could lose the ability to stay afloat. The new tube-based design is simpler and much more stable, especially in turbulent conditions similar to those found in the open sea.
“We tested them in really harsh environments for weeks at a time and we did not find any degradation in its buoyancy“, says Guo. “It is possible to make large holes in them, and we have shown that even if we severely damage the tubes with as many holes as possible, they continue to float“.
The team also showed that multiple tubes can be connected to form rafts, paving the way for applications such as ships, buoys and floating platforms.
The laboratory tests included tubes of different lengths, which reached almost half a meter. According to Guo, the concept can be expanded to support the heaviest loads used in the real world.
The team also explored how rafts built from these superhydrophobic tubes could capture energy from ocean waves. This approach points to a potential new way of generating electricity renewable — while using durable floating structures.
