Regularum libri
Ex libro III
Dig. 50,5,3Scaevola libro tertio regularum. His, qui naves marinas fabricaverunt et ad annonam populi Romani praefuerint non minores quinquaginta milium modiorum aut plures singulas non minores decem milium modiorum, donec hae naves navigant aut aliae in earum locum, muneris publici vacatio praestatur ob navem. senatores autem hanc vacationem habere non possunt, quod nec habere illis navem ex lege Iulia repetundarum licet.
Scævola, Rules, Book III. Exemption from public employments is granted to those who have constructed ships destined for the transport of provisions for the Roman people, which have a capacity of not less than fifty thousand measures of grain, or several, each of which has a capacity of not less than ten thousand measures, as long as the said ships are suitable for navigation, or where they provide others in their stead. Senators, however, are not entitled to this exemption. According to the Julian Law on Extortions, they have no right to have ships.