We had to build a boat that could hold the most pennies.  If your boat is longer then it would be better because it has more room to fit the pennies.  My groups boat ended up holding 66 pennies.  We thought it would be ideal if the boat was long and bowl-shaped so that it would fit the most possible pennies.  If I could change anything, I would change our boat from being less bowl-shaped into more of a flat boat so that the weight of the pennies will be more evenly distributed.