I'm reading Polybius' history, and he describes the Romans' initial attempts to build a navy as being troubled because they had no craftsmen familiar with quinquereme design.
They apparently solve this problem by using a beached Carthaginian design, but Polybius mentions that in their initial expedition to Sicily they "borrowed quinqueremes and triremes from Tarentum and Locri, and even from Elea and Neapolis; and having thus collected a fleet, boldly sent their men across upon it."
Why wouldn't the romans just copy these ships?
Were there any differences between the punic and the italian/greek quinqueremes that would lead the romans to prefer using the punic design?
Or is this whole section just mildly nonsensical? Or possibly just a poorly thought out parable about the crafty romans and their adaptability/gumption?
Short answer: we don't really know.
Longer answer: it is pretty clear that Polybios has in mind to emphasize the Roman lack of experience on the sea and to contrast this inexperience with Carthaginian naval mastery. Having said that, it is not implausible that the Romans did not have many "official" naval assets prior to this conflict. Syracuse was a new ally at this time, and this Greek city was the birthplace of the powerful penteres (quinqueremes). If we take it at face value, the story in Polybios of the Romans copying the Punic design does seem to suggest that the Carthaginian vessel had some kind of superiority. I personally would not be surprised -- in the 9th and 8th centuries, the Phoenicians were sailing from the Levant to the Straits of Gibraltar and beyond, down the Atlantic African coast and up the Spanish coast from their enclave at Cadiz. They had the best long-haul ship technology in the whole Med., and it would follow that their ancestors in Carthage would possess similar know-how. We don't have any really great examples of Punic warships from this time period. The Marsala Wreck and its sister come to mind, but it isn't clear that those were actually warships, and anyway they are too small to go up against Syracusan penteres anyway. There had to be much bigger Punic ships out there.
A really recent source for all things Roman maritime is C. Steinby, The Roman Republican Navy: from the 6th century to 167 BC (Helsinki 2007). I haven't looked at it myself but I know he draws on a lot of recent wreck evidence (which can be a little hard to find sometimes).