I found that I’ve been censoring myself when it comes to measuring quantities in storytelling. It’s part of growing up, I thought, it’s inappropriate to talk about buttloads of
shit in polite conversation. Not only was I wrong about what a buttload actually was, but I found that I’ve been throwing the terms around with no regard to their actual quantity. Were there boatloads or buttloads of people in line at the supermarket, or was there merely a shitload?

For arbitrary’s sake, I’ll be comparing these sizes in gallons of whiskey (not including the jug), which is less dense than water, and weighs about 7.7 lbs per gallon. I know this is problematic, what if you want to describe how many legos you used to own in terms of butt/boat/shitloads? What about abstract concepts like boatloads of fun? you’ll need to convert them yourself. This is just a mild attempt at understanding size differences.

Buttload: “A ‘butt‘ is a traditional unit of volume used for wines and other alcoholic beverages. A butt is generally defined to be two hogsheads, but the size of hogsheads varies according to the contents. In the United States a hogshead is typically 63 gallons and a butt is 126 gallons.”

I used to think buttload was just a mishearing of boatload, but nope, it is a butt distinct unit, from Middle English bote. From now on, I’ll probably start measuring things in hogsheads.

Boatload: “the cargo that a vessel carries or is capable of carrying.”
Thanks to the indefinite response from the dictionary, I guess it will depend on how big of a boat we are talking about (can be modified, huge boatload, tiny boatload). As an example, we’ll use one of the largest cargo ships, The Colombo Express.
The Colombo Express holds 8,749 Twenty-foot equivalent units (TEU), and while TEUs are hardly standardized, “the maximum gross mass for a 20-foot (6.1 m) dry cargo container is 24,000 kilograms (53,000 lb).[4] Subtracting the tare mass of the container itself, the maximum amount of cargo per TEU is reduced to approximately 21,600 kilograms (48,000 lb),” according to a Page That Cannot Be Found. Thrilling, that’s good enough for me. Math.
21,600 kg * 8,749 TEUs = 188,978,400 kg = 416,626 ,056 lbs
so,  416,626,056lbs / 7.7lbs = 54,107,280 gallons.

Shitload: After reading through a thread discussing a formula for calculating average poop size, minus the fiber and bacterial content, I’m siding with user “Dave” and agreeing that the avg poop is probably around .5 lbs, but since it varies daily with diet and health, and is messy, highly intricate and hard (or soft) to calculate, I’ll elect to use an interval of .5 ≤ x ≤ 2 lbs, so .065 ≤ x ≤ .260 gallons.