Polynesian sailing and navigation technology probably beats Roman on the open ocean. The Mediterranean is warm, pleasant and calm (boats did and do get wrecked

Polynesian sailing and navigation technology probably beats Roman on the open ocean. The Mediterranean is warm, pleasant and calm (boats did and do get wrecked by storms, but it's a much smaller risk). Distances between landing sites are short. If the wind dies, then it's feasible to row. You can stay in sight of land for travel to most destinations. The Atlantic and Pacific are wild and dangerous.