This is BM 1867,0101.1099.
I believe Pobjoy’s write up on this coin and most of the social war coins. 
The BM catalogue calls the scepter tied with a fillet the mast. This is just wrong. That is not what masts on ships on coins or gems look like.
addendum, later same day: This is the same description given in HN Italy 416–mast and sail–still wrong, but at least I know where BM is getting it, must check but probably also in Campana…
Filleted Scepter is clearly right reading BUT this is problematic to me because of it being iconographically unprecedented until later. That scepter tied with a fillet is a hallmark of the famous fleet coinage of Antony and also appears on the coins of Sextus Pompeius.
Also the hand shake with the prow in the background is an iconography of the civil war period (RRC 469, 470/1a).
Now all these parallels could have a common Hellenistic precursor, but if they do, I don’t know what it is (and that bothers me). I think it unlikely the later Roman Civil War types would copy Social War types.
It just makes me a little worried about the issue and its legitimacy, but there are a number of specimens which a good deal of variation…..
Liv Mariah Yarrow 