Wave Height Safety Calculator

How It Works

Significant wave height is the average of the highest one-third of waves — what experienced mariners estimate by eye. Maximum wave height can be nearly 2x significant height. Wave height depends on wind speed, fetch (distance wind blows over water), and duration. Short, steep waves (short period) are more dangerous than long-period swells. General rule: stay in port when waves exceed 1/3 your boat length. Pontoon boats are most vulnerable; sailboats handle waves best due to ballast and deeper draft.