The ISAW rules in the recent reprint of IO include rules for constructing warships (pg 286). The table on that page lists the costs as the Warship's Alpha Strike PV. Seems simple enough, building a Potemkin would cost 564 RP. That makes sense, a single warship and it's upkeep probably has a noticable impact on GDP.
But on the same page it also says that "Warships require a number of turns equal to their RP production cost to finish construction." Does that mean that it would take 564 turns to build a Potemkin? Each ISAW turn is a month so that would be 47 years? I have to be missing something here, right?