Methodology

This page explains how Boat Economics builds a calculation, not just that its numbers are estimates. The rules below govern every engine on this site before it is allowed to go live.

The order we trust an assumption in

Every number an engine uses, a slip fee, a fuel price, a maintenance reserve, a resale curve, follows the same priority order. A number you type in from your own quote or your own boat's history always wins. Below that, a manufacturer's own documentation governs anything mechanical, like tow ratings or engine hour intervals. Below that, an official U.S. government or Coast Guard figure. Below that, a dated, scoped number from a real industry association or provider price list. Only at the bottom of that list does an editorial estimate appear, and only when it is clearly labeled as a range rather than a fact. No engine invents a number outside this order.

Why we don't publish one national average and stop there

Slip fees in Florida and slip fees in Michigan are not the same number, and a single blended national average would flatter one reader and mislead another. Where a cost is genuinely local, storage, insurance, fuel, service labor, an engine is built to accept your own quote first and fall back to a sourced, dated range only when you don't have one. A range is shown as a range, with the source and the date attached, never dressed up as a precise figure.

What a calculation actually walks through

An engine's job is not to produce one number and stop. It states the decision being made in plain language, asks for a small set of inputs first, computes the literal answer, breaks that answer into the economics behind it, explains what the result means for the decision, and, where the underlying math supports it, solves for the specific change, more use days, a lower price, a different storage mode, that would change the outcome. Every formula is a pure, version-tracked function with its own tests: a hand-checkable example, a realistic case, an edge case, and a case that checks the formula behaves correctly when an input is missing or invalid.

What stays out of scope on purpose

Boat Economics does not simulate or certify towing safety, structural capacity, or seaworthiness. Tools that touch tow ratings, payload, or trailer weight perform conservative, deterministic arithmetic against numbers you provide from a manufacturer's plate or manual, and they say so plainly. They are advisory math, not a substitute for that documentation, and they will never claim otherwise. Likewise, no engine gives individualized financial, legal, or tax advice; it shows modeled outcomes under stated assumptions.

My Boat Plan and your data

My Boat Plan lets you save reusable details, your boat, your typical use, your storage setup, locally in your own browser so you don't retype them into every engine. It is optional, it never blocks a calculation, and no raw financial or usage figure you enter is ever sent to analytics or stored on a server. Details are in Privacy.

Review and correction

Sourced defaults are dated and reviewed on a set schedule; a user-entered quote always overrides a stale default rather than being silently replaced by it. If you find a formula or a sourced figure that looks wrong, tell us at help@boateconomics.com.