This is what I found
http://www.geocities.com/capitolhill/9226/navy.html
'The former Royal Insignia of Savoy Kings was replaced, since November 9, 1947, by this one that represents the four ancient Italian maritime republics Venice, Genoa, Amalfi and Pisa it is surmounted by the "Corona Rostrata" the Republican Crown with rostrums. The insignia is put in the middle of the national flag and it differs from the one of the Italian merchant Navy because it has the Corona Rostrata and the S.Marco lion has the book closed, a sword in the hand and the tail raised up. '
And here are the flags
http://en.wikipedia.org/wiki/Image:C...n_of_Italy.svg
http://en.wikipedia.org/wiki/Image:N...n_of_Italy.svg