Used-sailboat buying guides
Start with the design ratios: they are the numbers a listing quotes without explaining, and the ones that decide whether a boat suits the sailing you actually plan to do. The free calculators run the same computations on your own figures, and the pre-check runs them automatically on any listing URL.
Sailboat design ratios
The full set explained in one place: SA/D, displacement to length, ballast ratio, comfort ratio, capsize screening and hull speed. What each number predicts, and where it lies to you.
Read the guide →Capsize ratio
What the capsize screening formula measures, where the 2.0 offshore threshold comes from, and the limitations every buyer should know.
Read →Comfort ratio
Ted Brewer's motion comfort ratio: the formula, what counts as a good value for coastal or bluewater sailing, and where it misleads.
Read →SA/D ratio
How much sail power a boat actually carries, the standard 100% foretriangle convention, and the bands from 14 to 24 and up.
Read →D/L ratio
Light, moderate or heavy: the bands from ultralight racer to heavy cruiser, and why modern boats read lighter than they sail.
Read →Paste a listing URL and the free pre-check computes every ratio from the ad's own specs, alongside mission fit and the costs the listing doesn't mention.
More clusters are in progress: real refit and ownership costs, boat values, and the buying process end to end.