[SCAEUOLA libro tertio regularum. ] §50.5.3.prHis, qui naues marinas fabricauerunt et ad annonam populi Romani praefuerint non minores quinquaginta milium modiorum aut plures singulas non minores decem milium modiorum, donec hae naues nauigant aut aliae in earum locum, muneris publici uacatio praestatur ob nauem.
[By SCAEVOLA, in the third book of Rules.] To those who have built seagoing ships of not less than fifty thousand modii, or several ships of not less than ten thousand modii each, and have employed them for the grain supply of the Roman people, an exemption from public duties is granted on account of the ship, as long as these ships or others in their place are sailing.
senatores autem hanc uacationem habere non possunt, quod nec habere illis nauem ex lege Iulia repetundarum licet.
Senators, however, cannot have this exemption, because they are not even allowed to own a ship under the Julian law on extortion.