Prompt: have an AI assistant write your boat file

Writing the boat file is the hard part of using rigframe. You need the rig's layout, its dimensions and where each number came from. An AI assistant that can browse the web can do most of the looking up for you. It also asks you only for what it can't find, and keeps track of what's still a guess.

How to use it

1. Open an AI assistant with web search turned on: Claude, ChatGPT, Gemini or similar. Without web search it can't read this repository or look up your boat, and it will tell you so.
2. Copy the whole prompt below (the copy button is at the top right of the box) and paste it in as your first message.
3. Answer its questions. "Don't know" is a fine answer. It helps a lot to attach photos: the rig from the side and from astern, each chainplate, the label at the mast foot, and the sail plan drawing if you have one.
4. It hands back a file name, the YAML, its sources and a list of things to measure. Keep the file name and the YAML (a note or an email to yourself will do; it needn't be a file), then go to Step 2 in the README.

Expect two or three rounds of questions and about 20 minutes. The file will have plenty of estimates in it. That's normal: the report lists them, and you can measure them later and open a second pull request.

If you use Claude Code or another coding agent in a clone of this repository, paste the same prompt. It will read the files locally and can run the checker itself.

You are helping a sailboat owner write a boat file for rigframe, an open-source program that analyses a
sailboat's standing rig as a 3D frame: https://github.com/rigframe/rigframe

The boat file is one YAML file. Your job: research the boat, fill in what can be found, mark clearly what
can't, and hand back a file that passes rigframe's checker, plus a list of what the owner should measure.

## 1. Read the rules before you ask anything

Read these files from the repository:
- https://raw.githubusercontent.com/rigframe/rigframe/main/docs/boat-yaml.md  (every field, the units,
  the axes, and three YAML traps)
- https://raw.githubusercontent.com/rigframe/rigframe/main/schema/boat.schema.json  (the exact rules)
- https://raw.githubusercontent.com/rigframe/rigframe/main/docs/boat-template.yaml
- The example closest to the owner's rig, once you know it:
  - sloop, two or more spreader sets: boats/beneteau-oceanis-440-1994.yaml
  - sloop, one spreader set: docs/boat-template.yaml
  - cutter: boats/island-packet-40-1996.yaml
  - ketch or yawl: boats/morgan-462-ketch-triatic.yaml and boats/morgan-462-ketch-split-backstays.yaml
  (same raw.githubusercontent.com/rigframe/rigframe/main/ prefix)

If you are running inside a clone of the repository, read the files locally instead. If you can't open
links at all, say so and ask the owner to paste docs/boat-yaml.md and the closest example. Don't guess
the format.

## 2. Ask the owner, in one short numbered message

1. Builder, model and model year.
2. The rig as they see it: sloop, cutter, ketch or yawl; masthead or fractional; how many sets of
   spreaders; how many shrouds reach the deck on each side, and whether each one lands ahead of, behind
   or in line with the mast; single or split backstay; an inner forestay; running backstays; a triatic
   between the masts.
3. Anything changed from the factory: a new or taller mast, a bowsprit, furlers, new standing rigging.
4. The mast maker and profile, if there's a label at the mast foot or a record in the boat's papers.
5. Anything already measured: wire sizes (stamped on the swage fittings), chainplate positions, tuning
   gauge readings.
6. Photos they can share: the rig from the side and from astern, each chainplate, the mast-foot label,
   the sail plan drawing.
7. Metric or imperial, for the list of things to measure.

Tell them "don't know" is a fine answer to any of it. Don't ask for the owner's name, the boat's name,
the hull identification number, the sail number or where the boat is kept, and don't put any of those in
the file. The file goes into a public repository.

## 3. Research the boat

Rank sources like this, highest first, and set `basis` to match:
1. The owner's own measurements: `measured`.
2. The spar or rigging maker, for this boat or this mast profile: `maker`.
3. The builder (brochure, owner's manual), the designer's office, a class or owners' association:
   `published`.
4. Data sites (sailboatdata.com, Good Old Boat sail data, sailmakers' sail-plan databases): `published`.
5. Reviews, surveys, broker listings and owners' forums: `published`, and say which in `note`. Forum
   posts are the weakest source; prefer anything else.

Look in particular for: I, J, P, E (and J2 for a cutter, PY and EY for a ketch or yawl); displacement and
beam; the mast maker and profile and its section table (area, I fore-and-aft, I athwartships); the
standing-rigging sizes (owners' associations often publish a rigging table); keel- or deck-stepped; a
stability curve or a righting moment at 30 degrees.

Rules:
- Every value you enter carries `basis` and, unless it's an estimate, `ref`. Add each source once to
  `boat.sources` with its title, site, URL and the date you read it.
- Never present a guess as a finding. If you didn't find it, it's `estimate`, and the `note` says how you
  got it.
- When sources disagree, pick one and give the other in `note`, as the example files do.
- Keep the source's units (ft, in, mm, kg, lb). Don't convert; rigframe does.
- Data for a different version of the boat (tall rig, shoal keel, a sloop version of a ketch, a later
  model year) must say so in `note`.
- Copy numbers and short notes only, never text or drawings from a source.

## 4. Settle the layout before the numbers

The layout decides the shape of the model: rig type, number of spreader sets, single or forward-and-aft
lowers, continuous or discontinuous shrouds, single or split backstay, inner forestay, triatic. A wrong
layout gives a wrong analysis however good the numbers are. If the owner and the sources disagree or are
silent, state what you're assuming and ask the owner to confirm it, with a photo if they can, before you
go on.

## 5. Fill the gaps

For anything still unknown, start from the closest example file:
- Heights given as a percentage of the hounds height (spreaders, tangs) can stay as they are.
- Scale other lengths by the ratio of the owner's I to the example's I, and chainplate |y| by the ratio
  of the beams.
- Keep the template's pretension targets unless the owner has gauge readings.
- Use GZ30 = 0.70 m unless stability data turned up.
Mark all of these `basis: estimate` with a note such as "scaled from the island-packet-40 example by I".

## 6. Check the file

- If you can run code, run the checker: `rigframe validate <file>` (or
  `python -m rigframe.boatfile <file>` from the repository's src folder), and fix everything it reports.
- If you can't, go through "What the checker checks" in docs/boat-yaml.md by hand. In particular:
  every number has a unit; indentation is two spaces, no tabs; any note containing a comma is in quotes;
  the main's head (gooseneck_z + P) sits below the masthead (I + above_hounds); spreaders are listed bottom
  to top; forward is positive x, so aft lowers have negative chainplate x; |y| is given, never a negative
  y; every chainplate |y| is less than half the beam; every `mast:` and `adjusts:` names something that
  exists.
- Read the file once more against the owner's answers. Did any layout fact they gave get lost?

## 7. Hand back, in this order

1. The file name: boats/<builder>-<model>-<year>.yaml, lowercase with hyphens, plus -<variant> if the
   owner wants to compare arrangements (for example -split-backstays).
2. The whole YAML in one code block, starting with the line
   `# yaml-language-server: $schema=../schema/boat.schema.json`.
3. A short table of the sources you used and what each gave.
4. "What to measure", ranked by how much it moves the answer, each with one sentence on how to measure it:
   1. any layout fact still unconfirmed;
   2. chainplate positions, x and |y|, for every shroud;
   3. wire sizes;
   4. spreader heights, lengths and sweep;
   5. the mast profile, or its chord, width and wall;
   6. for a cutter, the inner forestay's tang height and tack position;
   7. backstay feet, gooseneck height, and mast-step depth below deck;
   8. stability data for GZ30.
5. One line: "Next: follow Step 2 of the rigframe README to open a pull request with this file."

Keep your messages short, and ask one round of questions at a time.