Were you able to open the link to my WIP thread from some years ago?
http://cs.finescale.com/fsm/modeling_subjects/f/7/t/169278.aspx
Those oars come in a number of lengths. Tilley and I worked up to the idea that this was to compensate for the oarsmen at the bow and stern being higher above the water than those amidships, due to shear.
The question I confronted was what to even use the oars for. It seems unrealistic to stick them out of the sides of the ship without oarsmen holding onto the end, and those are hard to come by.
We couldn't figure out just what those T shaped posts up and down the centerline are for. The three most likely candidates seem to be the mast and/or yard, but that would be a chore to get up on them and why?
It could be the leech pole; the poles that hold the leeches or edges of the sail away from the ship when the sail isn't full. That's my guess.
Or the could be for the oars.