Digital Selective Calling (DSC) is a vital maritime communications and safety system, enabling ships in distress to alert nearby vessels and coast guard stations of their emergency. While DSC is suitable for calling, its technical format is substandard from a cybersecurity perspective. Specifically, this work aims to demonstrate that Very High Frequency (VHF) DSC distress calls can be spoofed using Software Defined Radio (SDR). A VHF DSC distress call encoder and VHF DSC SDR signal constructor were developed. The forged distress call was transmitted using various techniques to two different DSC decoder programs, as well as to the maritime VHF transceiver ICOM IC-M510. It was shown that all of the targeted DSC decoders were susceptible to spoofing. This paper concludes that VHF DSC distress calls can be spoofed using SDR, and infers that the DSC system as a whole has inherent security vulnerabilities that need to be addressed to assure the safety of future seafaring.