For historical research, several digital archives host scanned copies of Jane's Fighting Ships that you can download or view for free:
Finding a legitimate depends heavily on which era of naval history you are researching. Because the series has been published annually since 1898, many older volumes are now in the public domain and available for free, while modern editions remain under strict copyright. Where to Find Free Legal Downloads janes fighting ships pdf free download link
Jane's Fighting Ships - Naval Historical Society of Australia For historical research