The need for pressuring the wealthy for more. In 242 BC, after some 20 years of warfare, Hannibal's father (one Hamilcar Barca) was the General from Carthage who finally was pinned down by Roman forces on a road above Drepana, near Trapani. Send for help. But in the meantime, Rome mustered a fleet to cut them off. The place of confrontation was the Egadi Islands, a few miles off the coast there. There were hundreds of ships and thousands of men, say accounts of the Greek hstorian Polybius. That could be exaggerated, but makes the point: this was important.
Rome's ships, under the commander Lutatius, included the "quinquiremines" -- fast ramming ships, with oarsmen, trained troops, and fast because they carried no extra stores. Carthage had heavy-laden ships and inexperienced -- there for an emergency only, hastily mustered. The weather was bad, but Lutatius gambled that his best chance lay in attacking while Carthage was disadvantaged. Perhaps Lutatius struck by ambush at sea.
And the Roman ships were fitted with rams: triple-stacked blades, shaped like an arrow head rather than a blunt ram, two feet wide, that rode just under the waterline, to splinter planks on enemy vessels and cripple them, while preserving the integrity of the Roman ship.
The town of Trapani launches ferries today to the islands, and undersea explorers continue to bring up barnacled rams, helmets, pottery storage amphorae for carrying oils and wine. Without the rams, this could be seen as just another site of many ship sinkings; the rams mean war. The damage from impact seen on them shows the violence of that impact.
How to pay for them? One practice: the Romans "pressed Rome's 200 richest families to sponsor warships." See Archeology Magazine, January-February 2012, The Weapon that Changed History, Evidence of Rome's Decisive Victory over Carthage is Discovered in the Waters off Sicily, by Andrew Curry, at http://www.archaeology.org/1201/features/sicily_rome_carthage_navy_rams.html
Triremes, quadriremes, quinqueremes, penteconters, the Roman victory over Carthage was not only a victory of design and training, unencumbered by vast stores on board; but also the tactic re-emerging today. Is this Rome's percent? Who can research that? The 200 richest tapped for funds. Galleys needed rams. Where else to go.
When you need to tap the richest to accomplish important societal goals, do it. Rome found the money in the coffers of Rome's richest to pay for it.