Please note that Mommsen uses the AUC chronology (Ab Urbe Condita), i.e. from the founding of the City of Rome. You can use this reference table to have the B.C. dates
From: The History of Rome, by Theodor Mommsen
Translated with the sanction of the author by William Purdie Dickson
Defeat of the Roman Fleet before Drepana - Annililation of the Roman Transport Fleet
But the new consul Publius Claudius considered the task of maintaining the investment of Lilybaeum too trifling: he preferred to change once more the plan of operations, and with his numerous newly-manned vessels suddenly to surprise the Carthaginian fleet which was waiting in the neighbouring harbour of Drepana. With the whole blockading squadron, which had taken on board volunteers from the legions, he started about midnight, and sailing in good order with his right wing by the shore, and his left in the open sea, he safely reached the harbour of Drepana at sunrise.
Here the Phoenician admiral Atarbas was in command. Although surprised, he did not lose his presence of mind or allow himself to be shut up in the harbour, but as the Roman ships entered the harbour, which opens to the south in the form of a sickle, on the one side, he withdrew his vessels from it by the opposite side which was still free, and stationed them in line on the outside.
No other course remained to the Roman admiral but to recall as speedily as possible the foremost vessels from the harbour, and to make his arrangements for battle in like manner in front of it; but in consequence of this retrograde movement he lost the free choice of his position, and was obliged to accept battle in a line, which on the one hand was outflanked by that of the enemy to the extent of five ships --for there was not time fully to deploy the vessels as they issued from the harbour--and on the other hand was crowded so close on the shore that his vessels could neither retreat, nor sail behind the line so as to come to each other's aid.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/3-02-war-rome-carthage-sicily.asp?pg=42