# Methodology

> How Catamaran Index collects, checks and dates its charter price data, and what the numbers do and do not mean.

URL: https://catamaranindex.com/methodology/
Last updated: 2026-10-28
Author: Catamaran Index editorial team

## What we publish

- **Monthly average weekly catamaran prices** (our only monthly series, so far) per destination, taken from the public destination pages of the broker 12 Knots, which state their own methodology: "Monthly average prices are calculated from all qualifying weekly charter price records" for N unique boats, "using departure dates in the current and following calendar years". All pages read "Updated October 2026" when we checked on 27 Oct 2026.
- **Annual averages for catamarans and sailboats (monohulls)** in Croatia and Greece from Mali brodari, who report an analysis of yacht-rent.com data ([Mali brodari](https://malibrodari.hr/en/croatia-has-more-charter-boats-than-greece-but-earns-less/), checked 27 Oct 2026).
- **Cost lines** (skipper, fuel, port fees, extras, deposit, APA, tips) from dated public guides, cited where they are used.
- **Licence rules** from the RYA, Anchor and The Moorings, quoted, with conflicts shown rather than resolved.
- **The Globe Sailor's budget tables** (catamaran and sailing yacht, 11 areas, prices recorded September 2026, boats under 5 years old with 4 cabins / 8 people) ([The Globe Sailor](https://www.theglobesailor.com/blog/what-it-really-costs-to-charter-a-yacht), checked 28 Oct 2026). The tables don't state a period for every column: we read skipper as per day and port fee as per night (both from the article text) and fuel as per week, and we never call the "Boat" column a weekly price.
- **Definitions** (yacht charter, bareboat, gulet, skipper) quoted from Wikipedia, with the article's last-edited date.

## Rules we follow

1. **No invented numbers.** Every figure links to a public source and a "checked on" date. If we cannot verify a figure, we show a qualitative statement or nothing.
2. **We don't copy partner listing prices.** Booking platforms' terms may restrict reuse of their prices, so we don't scrape or republish them.
3. **Our arithmetic is labelled.** Ranges (min–max of monthly averages), ratios, worked examples and the derived figures below are our calculations on sourced inputs, marked "our arithmetic" or "our label" where they appear:
   - **Season labels** on the month and boat-type pages rank a destination's 12 monthly averages: its 3 cheapest months are "low", its 3 priciest "peak", the rest "shoulder".
   - **"vs its cheapest month"** compares a month with the same destination's lowest monthly average.
   - **All-in estimates** add The Globe Sailor's fuel, 6 marina nights, mandatory extras and food at €20 per person per day for 8 people to the monthly charter average. **Per-person** figures divide by 8 (by 7 on skippered pages, assuming the skipper takes a berth).
   - **Skippered weeks** add 7 days of the destination's listed skipper rate to the charter average.
4. **Euros as published.** We don't convert currencies, to avoid adding an unsourced exchange rate.

## Limitations

- We have **no verified public price averages for motor yachts, gulets or crewed/luxury charters**, and no verified weather source for the Mediterranean or Thailand, so we show none and write "not verified yet". We show sourced cost structure (APA, gratuity, skipper) instead.
- 12 Knots' averages mix bareboat and crewed listings and all boat sizes, and they are **asking prices** before discounts and extras. A small fleet (e.g. Belize, 18 boats in the sample) makes averages volatile.
- One platform's inventory is not the whole market.
- Licence rules change and charter companies can be stricter than the law.

## Data download

All price figures are in a dated CSV: [/data/prices-2026-10.csv](https://catamaranindex.com/data/prices-2026-10.csv). Each row includes the source URL and the date checked.

## Updates

We re-check sources monthly and publish a new dated CSV each time. Spotted an error? [Tell us](https://catamaranindex.com/contact/).

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