Modern ships of war by Sir Edward J. Reed and Edward Simpson

7. A vessel has been in time of war destroyed by a submarine boat.

The latter, it is true, was also sunk, but it was for reasons that are no longer in force. As yet no perfectly successful boat of this type has been tried in any naval war, but there is no question that they will be used at the very first opportunity. Compared with a surface boat, the submarine has the following advantages: