In the year 1519, Ferdinand Magellan and his crew set sail on a landmark journey. With generous funding from King Charles I and the latest in navigational technology, Magellan's expedition departed westward from Spain, towards the legendary “Spice Islands” of the Far East. In the process of discovering a new route to the islands (Indonesia), Magellan and his crew accomplished an even grander milestone, all despite heavy casualties comparable to those seen in naval battle, casualties including Magellan himself. After three years, four ships, and 232 lives lost, the Victoria finally returned to Sanlúcar de Barrameda, the expedition's port of origin, without its captain, after circumnavigating the globe for the first time in human history.
Of course, Magellan had decades of sailing experience, which is why we're aiming first at a more modest target: a journey from San Francisco to San Diego. This closer, more easily-accessible port allows us to construct a boat using fewer materials and relying less on costly, heavy-duty, marine-grade components
Today's inexpensive construction materials and abundant electronics offer us the opportunity to match the achievements of Old World explorers, for far less of the cost. We aim to prove the viability of low-cost, low-volume sea transportation, making the oceans more accessible to low-budget scientific and business endeavors—not to mention how cool circumnavigating the globe would be in and of itself.
Nautical humorists affectionately hold the substantial cost of boating close to their hearts. They refer to boats as “holes in the water you throw money into” and use the acronym BOAT, meaning “bust out another thousand,” to mask the unfortunate business of boat payments and repair. But today, with access to inexpensive materials and vast knowledge, we can significantly reduce the cost of ocean transport.
Other robotic boats on Kickstarter have asked for up to $80,000, but we believe that we can be successful with a minimum of $2,000.
The rover relies on the innovative use of three principle resources:
1. Plastic piping and other plumbing hardware
2. Electric motors and drive systems
3. Arduino communications and motor management
Each of these resources is inexpensive and ubiquitous—everything off-the-shelf, no custom castings or machined parts. Using the materials described by the above list, we have painstakingly designed a robust, capable frame that will be able to navigate to pre-programmed waypoints. This first vessel will have no additional function besides autonomous travel, proving the ability of a low-cost, self-guided Sea Rover to navigate and withstand the rigors of the ocean.
Consistent with our guiding mantra, “more bang for the buck,” we are using PVC and ABS plastics to construct a simple, rugged frame. This material choice makes the design process flexible and assembly a breeze—especially since so many plumbing parts are available at the local home improvement store.
We decided on a pontoon design for its simplicity and stability. On top of two large pontoons rests the frame for our electronics and other hardware—simple and robust. Below the pontoons a keel filled with concrete and corrugated plastic sheeting keep the boat upright and traveling in a straight line.
As a precaution against unforeseen accidents, where the hull could crack or be otherwise punctured, we also filled the hull with a high-volume, low-density foam. Hopefully, this measure will prevent any kind of catastrophic failure. We want to assure that the rover will stay afloat regardless of any adverse conditions.
When we began the project, we planned to rely on a combination of wind turbines and solar panels to power the boat; such a system would provide consistent power supply in all weather conditions and at all times of day. However, through early experimentation, we found that making an efficient wind turbine from scratch is not a viable option. The high power output of wind turbines relative to their costs has led us to conclude that purchasing a wind turbine is the best choice. We will, in addition, continue to use a solar panel to power the navigation computer, satellite tracking, rudder controls, and government-mandated navigation lights. This split power system will also help diminish the vessel's dependence on expensive, heavy, fickle batteries.
We evaluated low-cost, brushless hobby motors as a means of propulsion. Unfortunately, the effects of corrosive saltwater and the limited lifespan of brushless hobby motors deterred us from using such a system. We looked instead at trolling motors—electric motors designed for marine applications that are more expensive, but much more reliable. With our current fundraising goal, we plan to use freshwater trolling motors and apply our own saltwater-resistant coating. If we pass our fundraising goal, we will be able to afford the pre-coated, saltwater trolling motors as a better option. The electricity driving these motors will come exclusively from wind power.
To guide the Sea Rover, we turned to Arduino—an open-source prototyping platform that is both easy to program and troubleshoot. By giving it a data-logging Arduino shield and a GPS module, we will provide the Sea Rover with a self-contained navigation system, costing less than $100. Three of the team members have previous computer science experience, allowing the boat's software to be coded specifically to the needs of the boat. We will post the final code in an update once finished.
Into The Future
We believe that personal sea rovers need not be impractical or expensive. Someday, marine biologists may regularly use robots as long-term mobile laboratories—coffee table-sized vessels floating from point to point in the ocean, collecting data and performing research. Rovers will have an application transporting goods to offshore oil platforms, ships, or the currently proposed offshore cities that will be built in the coming decades. Although safety and legal restrictions will likely prevent land and air transport from becoming autonomous in the near future, efficient, unmanned ocean vessels certainly present an exciting vision for the future.
Risks and challenges
Nearly every obstacle facing the Sea Rover stems from its immersion in the Pacific brine. The most daunting problem is corrosion—from salt and ultraviolet rays (sunlight). Other issues include California's kelp forests, collisions with other craft, and electronic failure.
We're combating corrosion by using ABS and PVC plastics, which are chemically excellent in cold saltwater and are fairly resistant to UV radiation. We still plan to coat the hull in UV-absorbing paint and saltwater resistant chemicals.
To avoid kelp, we have two fundamentals: avoiding kelp, and getting out of kelp. The former involves using deepwater channels where kelp struggles to grow and the latter involves installing a sloped bow to allow the boat to cut over forests. The propellors and rudders are protected by the keel.
To avoid other boats, we're installing a Coast Guard regulation navigation light with a visibility rating of two nautical miles.
To avoid electronic failure, we're sealing all electronics in the communication tower and filling the tower with moisture-absorbing silica beads. We also have multiple test trials planned to debug software and perfect navigation abilities.
- (30 days)