Kiero - thanks for the input. I know you did a lot of work for your Greek-inspired campaign, and I appreciate having another pair of eyes look this over.
The number of crew comes directly from the article Actium: End of the Roman Republic, by David R. Higgins, in Strategy & Tactics #201. While the numbers you cited for a Greek trieres are correct, a Greek trieres under these rules would be a light aphract trireme, and would have a maximum of 10 marines, 4 fewer than the historical number. The 15 “sailors” are all non-rower, non-soldier crew, which (on a Greek trieres) consisted of the trierarch (captain), kybernetes (helmsman), prorates (lookout), keleustes (bosun), pentekonteros (quartermaster), naupegos (carpenter/shipwright), auletes (piper), and 10 actual sailors, for a total of 17 “sailors”, 2 more than listed on the trireme description. I will admit to having 10 more rowers than the Greek trieres is generally listed with, so under the current rules, a Greek trieres will have 4 more people on board than it should - 10 extra rowers, 4 fewer marines, and 2 fewer sailors. If you have any sources regarding the crewing of larger polyremes, I would appreciate knowing what they are, since I am always looking for more information.
With regards to bireme, trireme, etc, the reme portion comes from Latin remus (“oar”), while the Greek version is eres (“rowing”) - hence a trireme in Latin is a trieres in Greek. The Latin is clearly not literal (i.e. “two-oared” up to “ten-oared”), since a quadrireme would not work, let alone a decireme, if it was literal oars. Three is the maximum number of rows that works. Four doesn’t work at all. Five is right out. Instead, the Greek is more correct in its terminology, and it refers to the number of rowers in each vertical column - a “two-rowing”, a “three-rowing,” etc, up to Ptolemy’s tesserakonteres, the “forty-rowing,” which was a catamaran of two “twenty-rowing” vessels attached to each other, thus being a (twenty plus twenty) “forty-rowing.” The number of levels is irrelevant with regards to the nomenclature of the ship in the Greek, and the Latin is just confusing. As hull length and ship mass grew, the number of rowers needed to move it adequately increased, which is why the “two-rowing” is smaller than the “three-rowing,” etc.
Oarsman quality is currently only tracked indirectly. The single-level modification abstracts the ability to use the a scaloccio rowing style (to anachronistically use a Renaissance Italian term for a method used well before the Renaissance) into a reduced maneuverability and lower cost for rowers, as the ship needs only one trained oarsman per oar. The use of slave rowers would mean lower morale, as with other hirelings, which will affect attempts to reach and maintain top speed.
The Light Hull modification was intended to reflect a thinner hull more than an open hull, but I will think about how to incorporate open hull forms into the rules so that rowers are easier to target.
Speeds are another area where I expect to have revision. The current numbers are from the Actium article, but I am still doing research on this plus other topics (I have around 5,500 pages of various naval archaeology papers on my to-read list at the moment). I also need to make a short road trip to one of my alma maters, since they have copies of “The Shorter Science and Civilization in China: Vol. 5”, “The Archaeology of the Roman Economy”, and “Mechanics of Pre-industrial Technology : Introduction to the Mechanics of Ancient and Traditional Material Culture”, all of which I believe will help me add to the rules. Right now, the maneuverability of the heavy polyreme is its only disadvantage, but that’s subject to change.
On the topic of oar-shearing, I just haven’t gotten there yet. As with rules for sailing vessels, it’s on the to-do list.