Researchers in Singapore are testing a sailing probe that is dropped from the air, lands on the water and then continues on its own, like a small ghost ship. Unlike floating research vessels, such as those deployed by sailors like Boris Herrmann and Arved Fuchs, it is capable of propelling itself under sail. The craft, aptly named “Albatross”, differs from existing sailing drones in that it is dropped from the air and is designed for short-term use. So far, the concept has only been tested in sheltered waters.
This ‘ghost ship’ comes from the sky
Anyone travelling on the Baltic Sea, the North Atlantic or the major ocean routes today must not only expect to encounter cargo ships, fishing vessels, pleasure craft, flotsam and lost equipment. Autonomous research vessels are also increasingly criss-crossing these waters: drift buoys, Argo floats, underwater robots and small sailing drones.
Just how suddenly such a device can appear was demonstrated in the summer of 2024 by a two-metre-long Sailbuoy north of the Kriegers Flak wind farm. It was sailing autonomously between waypoints, but had neither AIS nor position lights nor a radar reflector. A YACHT reader spotted it on its way to Sweden.
Now there is another, even more unusual variant: a sail-powered probe that falls directly from the air onto the water.
Landing like a maple seed
The platform is called “Albatross” – short for Airborne Lander with a Buoyant, Auto-Rotating, Sailing Sensor. It was developed by researchers at the Singapore University of Technology and Design. The principle is as follows: the probe is dropped from a manned or unmanned aircraft. Its two rigid wing-like sails cause the fuselage to enter autorotation, much like a maple seed. This significantly slows its descent.
In tests, a small prototype was dropped from a height of 150 metres by a drone. After a brief phase of free fall, the rotation stabilised, slowing the descent and cushioning the impact on the water. The device then righted itself in less than a second, as its centre of gravity lies low in the keel. This is designed to enable the platform to return to an upright position even after capsizing.
From a missile to a sailing boat
On the water, the wings become sails. “Albatross” can navigate to pre-set waypoints using GPS and a compass. Just three small servomotors are needed to control the sail position and heading: one for the front wing sail, one for a control surface on the main sail, and one for the rudder.
The rudder is particularly unusual: not only can it steer, but it can also beat from side to side like a fish’s tail fin. In light winds, it provides limited additional thrust and helps the probe to turn or cross the wind. During sea trials, the larger test version reached speeds of up to 0.82 m/s, or just under 1.6 knots. During an autonomous voyage lasting around three hours, it also recorded environmental data. Anyone wishing to see how it works can find it at the Development team footage of launch and sailing trials.
No substitute for drifting measuring buoys
“Albatross” is not intended to replace existing measuring buoys. Such drifters are designed to drift with the wind and currents and transmit data over long periods; Argo floats create profiles of water masses by repeatedly rising and sinking. Their strength lies in long-term observation, not in navigating precisely to a waypoint.
Sailing ships take these measuring instruments to areas of the sea that research vessels rarely reach: Boris Herrmann deployed a drift buoy during the 2024/25 Vendée Globe and continuously recorded surface water data using his OceanPack. Also Arved Fuchs uses the ‘Dagmar Aaen’ as a measurement platform. In the North Atlantic His crew are also testing a drift buoy with a wooden body, which measures air pressure and water temperature and is designed to leave less harmful rubbish in the sea.
This new development from Singapore fills a different niche: it could be deployed to a specific area in a relatively targeted manner, navigate on the surface there and then – at least in theory – be retrieved again. This would be an advantage for time-critical observations.
In the long term, the researchers envisage potential applications in the event of oil spills, algal blooms, following extreme weather events, or during other time-critical measurement campaigns in remote areas. Instead of first sending a ship to the affected region, a manned or unmanned aircraft could rapidly deploy the platform. It would then continue to operate using wind power.
No road users yet on the open sea
‘Albatross’ is not yet a production-ready sailing drone for the world’s oceans. Trials to date have taken place in sheltered waters near Singapore. The developers themselves point out that the small prototypes are not yet built to withstand large waves, strong currents, rough seas and long missions on the open sea.
It also remains to be seen how the vessel would be made visible during subsequent operation. AIS, radar reflectors, navigation lights, collision prevention and the legal classification of small autonomous vessels are issues that need to be clarified for such systems before they can operate regularly in busy waters. The example of the Saildrone shows that sometimes they just suddenly appear.
In your view, what markings should small autonomous research vessels carry so that sailors can spot them in good time? Join the discussion.
Ursula Meer
Redakteurin Panorama und Reise