Maritime cyber threats are on the rise, yet sailing ships lack typical IT support. When cyber incidents occur at sea, ships are isolated. To address this, a novel concept is introduced: the "digitally invisible ship." This proposal eliminates inbound open ports, thwarting malicious scans and reducing intrusion risks. Crucially, it requires no additional hardware or heavy software, seamlessly integrating with existing maritime systems. This innovation promises to revolutionize maritime cybersecurity, offering a robust defense against evolving threats.