Just a possibility: maybe make little indentations or alternatively little “bumps” (like how some people model rivets, using tiny drops of PVA glue applied with a toothpick or needle) along the length of the planks, to better emulate the appearance of either a mortise and tenon joint hull or a sewn/lashed hull. It should make the boat look more archaic, which I imagine is the look you’re wanting to go for. Otherwise, as you clearly haven’t gone for a clinkered hull, there might be a risk that the boat will look carvelled, which might be too “high-tech” for you. I know you don’t like crossbows in your Hyborian Age headcanon for similar reasons. A world, modelled after real history, that hasn’t advanced to crossbows presumably hasn’t advanced to carvelling, either.