Brewer’s comfort ratio, you need to run the following formula: Comfort ratio = D ÷ (.65 x (.7 LWL + .3 LOA) x Beam↑1.33), where
displacement is expressed in pounds, and length is expressed in feet.
You can use the following guidelines to interpret comfort ratio results: numbers below 20 indicate a lightweight
racing boat; 20 to 30 indicates a coastal cruiser; 30 to 40 indicates a moderate
bluewater cruising boat; 50 to 60 indicates a heavy
bluewater boat; and over 60 indicates an extremely heavy bluewater boat. If evaluating a larger boat, say 45 feet or longer, expect your results to be skewed a bit higher on this scale; if the boat is quite small, say 25 feet or less, they will be skewed slightly downwards.