Math For the Boat

How to make your Goat Float

The Facts:


Weight of water: a gallon of water weighs approximately 8.33 pounds


One gallon liquid US in volume(amount of space) converted to cubic inches equals precisely to 231.00 cu in – in3



Phil’s goat weighs 200lbs.

  1. How much water will we need to displace?


We know a gallon of water weighs 8.33lbs

What is the Goat’s weight in gallons?

200lbs/ 8.33lbs = 24.09 gal

How much volume (in space Cu/in) does 24.09 gal displace?

We know that 1 Gal. equals precisely 231.00 cu/in – in3 (that is how much space it takes up!)

If we multiply the #of gallons (we got for the goats weight) by the volume of one gallon we find the volume of water the will be displaced.

24.09 gal x 231 cu/in = 5566.26 inches

Answer: In order for the goat to float we must displace 5566.26 cubic inches of water.


  1. We need to figure out how big our boat will be so it is stable (not too tippy) and strong enough(structrure) to support our weight with out collapsing the boat.

I know my paper for the boat is 38” (inches) wide. I will make the walls of the boat 6” tall (because that seems to be about right based on how much a canoe and kayak sink in the water).

If I subtract 12” (total of two 6” walls) from 38” I get 26” for the bottom of the boat.

This is the one number I know in the Volume formula (LxWxH=Volume).   To get started I take my total volume from above 5566 cu/in. and set my height at 1.

L x 26 (wide) x 1 (high)=5566 cu/in

Answer: The length is 214 inches (5566/26=214) but keep reading…..

That will make a really long boat and I want a boat closer to 100 inches. So ajust the Height until the Length is closer to 100.


Goat Floats!