Expert System - Sailing Ships by McGoo Software

Based on the responses you have made:

The vessel is probably a Barque

Conclusion Notes:

This sailing ship has 3 or more masts with square sails on just the first 2 masts.

Expert System Rule:

IF the number of masts on the vessel is 3 or more
AND there are square sails on first 2 masts
THEN the vessel is probably a Barque.

Calculated Certainty Factor: 0.63 = probably