Our template value of 36 indicates that comfort is a high priority on cruisers. Large values resist rolling forces. A heavy rig can greatly increase I, with little impact on displacement. The roll period is based on the moment of inertia. Simply stated, a sailboat's roll period, in seconds, is inversely proportional to its stability.
Unstable boats have long periods, stable boats have short periods.
Then count the number of full cycles in one minute, and divide into 60. The general rule of thumb is that boats with periods less than 4 seconds are stiff and periods greater than 8 seconds are tender. The template value of 4.05 is near the stiff end of the range, indicating good static stability. This is another empirical term relating period and beam to stability. Values less than 1.0 are considered stiff.