Summary

UPDATE: 6/23/15

I redesigned the pennyboat. It is essentially a new design. It uses less than half of the previous boat's material and holds much more weight before sinking. Below are some stats on all my tests based on the Slic3r settings I used and http://gcode.ws/

I still need to design the sail and upper mast, but that is still in-process.

pennyboat_mini2 (80% Fill)
Est Filament used: 64.66grams
Est Penny mass: 2.5grams
Max Load: 57 pennies (142.5grams)
Percentage Load/Weight: 220.384%

pennyboat_mini (80% Fill)
Est Filament used: 155.07grams
Est Penny mass: 2.5grams
Max Load: 45 pennies (122.5grams)
Percentage Load/Weight: 78.997%

testboat1_mini (20% Fill)
Est Filament used: 4.34grams
Est Penny mass: 2.5grams
Max Load: 1 penny (2.5grams)
Percentage Load/Weight: 57.604%

testboat1_mini (50% Fill)
Est Filament used: 5.31grams
Est Penny mass: 2.5grams
Max Load: 1 penny (2.5grams)
Percentage Load/Weight: 47.081%