GPS has been used to navigate commercial vessels of all sorts since its inception, but the possibility of hackers exploiting vulnerabilities in satellite transmissions to jam them or even spoof data could render such navigation equipment unusable, and ship manufacturers and other related companies are responding to the threat by working toward developing alternatives to GPS for naval navigation. The frontrunner in the race to dominate this new navigation field is an Earth-based radio wave technology called eLoran, with navigation technologies based on it being developed in South Korea and the United States, while others like Russia and the UK are looking into similar alternative technologies to facilitate ship navigation.
There have already been confirmed cases of malevolent satellite interference causing boats' navigation systems to go haywire, and the potential for a disaster is already there. One example includes a number of South Korean vessels that had to return to their ports because of satellite jamming that reportedly came from North Korea, though North Korea never claimed responsibility for the incident. GPS disruptions have also been reported by the U.S. Coast Guard in the past. The widespread disruptions are likely enabled by the fact that GPS is relatively easy to disrupt - commonly available jamming hardware, or even a homemade kit can interrupt GPS signals, since they come from satellites in space all the way to individual devices on Earth. With how much of a risk modern hacks pose and how dependent ships are on their navigation systems, even the "father of GPS" Brad Parkinson supports eLoran and similar solutions as back-ups.
The stakes on replacing GPS for ship navigation are extremely high. Barges routinely carry millions of dollars or more in merchandise, and about 90 percent of international trade happens by sea. Such gigantic barges are hard enough to navigate with reliable systems, but should a vessel at sea lose GPS navigation, it could end up running out of fuel while floating aimlessly, which could result in it sinking, or even colliding with another boat. Loss of both material goods and life in such a scenario could be extremely high, given the sheer size of barges and how many staff are usually on board of such vessels, with major pollution from leaked fuel being another potential problem in these cases.