The pirate ship acts as a balance. On each side, there are three posts, spaced at equal intervals, from which the participant can hang weights. A weight on post 2 has twice the effect of one on post 1, and a weight on post 3 has 3 times the effect. Participants can choose from brass rings marked with weights ranging from 1 to 10. The goal is for the two sides of the ship to balance.

For example, if the participant places a 2 and a 3 on post 1 on the left, and a 5 on post 1 on the right, the ship will balance. A 6 on post 1 on the left will balance a 2 on post 3 on the right. Encourage the participants to explore the balance and understand the multiplication and addition principles at work.

In addition to the marked weights, there are special pieces shaped like Pirate X and Lady Y. Each Pirate X weighs a different amount, but the pirates all look the same and the weights are not marked. The same is true for the Lady Y pieces. Challenge the participants to determine the weight of a Pirate X or Lady Y.

As an extra challenge for more advanced visitors, let them find two ways of balancing a Pirate X and a Lady Y together so that they can solve for both weights simultaneously. Make sure participants understand that they need to move at least one of the two unknown pieces for the second weighing, in order to have enough information to solve for the two weights.