Either keep the two-page option and make it easier to access for new players, or just add an extra column. You could even include an option to toggle between the two in the settings.
I’ve always liked how villagers have two clear paths — one for eco buildings and one for military buildings. Why not do the same for the dock? One branch could be for eco ships like fishing ships, transport ships, trade cogs, fishing lines, and gillnets; the other for military ships and their upgrades.