Original Reddit post

My interest spawned accidentally after I used the Earhart story as a class subject for some of my older students. After reading about the possibility she could have survived on the island I had a load of questions that couldn’t be answered simply, all involved big tables of data and I’m useless at visualising data in my head. And when I could find a site that did what I wanted I decided to make it. The research phase was about 2 months once I opened the can of worms. I needed to find verified data on

• The actual island
• Reconstructed tide times
• Wind and surf
• The Lockheed Electra
• Any survey heights
• Radio ‘reports’ heard The plan was to put everything in so you can see what didn’t happen as opposed to trying to push a narrative. The more I researched, the more I needed to research more. I ended up buying the og drawings of the plane so I could get the measurements I needed. The key part I discovered was finding a place she could land that would mean she was able to make any of those radio calls because she could not have kept transmitting for days without running an engine, and the propeller needs clearance above the water to do that That was the main goal. To be able to place her anywhere on the reef and see if those calls could be possible. The other thing we need to explain is why the plane is not there now. So the plane would have to be somewhere the tide is deep enough at it’s highest tide in that week to float her off the reef and into the depths below. This tool can show you what’s not possible, under a couple of different assumptions:
• The empty fuel tanks were sealed and the only source of buoyancy
• The plane was completely sealed and bouyant. If the plane can’t float even when when it’s perfectly sealed (unlikely) we can determine it most likely can’t float in any other situation, amongst other theories. What it does ( Claude wrote this bit)
• A 3D model of the island you can walk around on your phone. Nikumaroro’s reef, lagoon and beach, built from 19 surveyed reef heights and published coordinates, with the 1937 tide running across it. Touch-first: drag, pinch, tap. No app, no login, nothing collected.
• The tide of July 1937, hour by hour. The water level comes from a fitted 1937 tide curve, checked against a published 2006 table and two independent sources. You can scrub through the whole week or press play and watch it rise and fall.
• Put her on the reef. Drop a Lockheed Electra on any spot and see how deep the water gets at her wheels through the week. The model answers in three ways only: could have, can’t have, or not enough data. It never says “this is what happened.”
• 139 reported radio signals, tested one at a time. Every post-loss radio report in the record, with its time window, gets checked against the water at the plane. If the water was over the limit when a signal was heard, the model says that signal can’t have come from a plane parked there.
• A physics engine that rules things out, not in. Tail lift, when the propellers would touch the reef, whether a sealed airframe could float. All of it derived from the aircraft’s licence weights and tank drawings, and it stops and says “unresolved” when the inputs run out.
• Fly the route yourself. A separate flight map: pick whose fuel estimate you trust, drag her track, and the radio log judges whether your route fits the record. A route that fits hands its landing time straight to the island.
• Betty’s notebook, line by line. A 15-year-old in Florida wrote down a voice she thought was Earhart. Her fragments, both sides of the argument, and a button that tests her timing against the island’s water.
• The expedition, now. A dated news card on the front page: a team is on the island as I write this, scanning the exact spot the model marks. The card says only what has been announced and nothing more.
• Every number can say where it came from. Three labels everywhere: verified, derived, illustrative. Guesses are drawn as dashed lines and chips, never as geology.
• Case for / case against on every contested point. Same size, same weight. Settled facts are not given fake doubt and open questions are not given fake answers.
• Built for English learners (B1 to C1) and anyone curious. Plain sentences, the grammar of evidence (must have, might have, can’t have), and a tap-to-find-out layer that is still being written.
• One self-contained HTML file per page. The island is a single 2.5 MB file with the fonts and data embedded. The only outside request is three.js from a CDN. Works offline once loaded. What I found interesting was looking for spots where both radio signals that sounded most credible to me, and bouyancy water depth could happen simultaneously. There are a load of radio signals reported, and a couple of them seem rather plausible. Being able to look for that sweet spot was the main purpose. ###The Tools I used Claude: Opus 5.5 medium, Fable 5.1 for orchestrating. Coding I used Opus 5, 5.5 medium, high, ultracode, Fable 5.1 and GPT astra I started with Fable as it had just come out and it wrote the overall spec which inevitably was deviated from after time. Opus 5, 4.6 was coding it. That was for the initial flight map and island. Afterwards I used Opus 5.5 as it was far less token heavy, and when I saw that it hardly made a dent compared to fable, and that’s what when me on to make a mistake. The biggest error I made was getting Opus 5.5 on ultracode to build a replica of the plane. The most important part that the entire model had to be correct around was the distance between the propeller tip and the reef so we could work out when it would be impossible to transmit. Researching was a pain and then ultracode took about 4 days to knock it out. It just kept checking and checking using you to annoy 5 or 6 agents. I kept an eye on my usage limits and using the 14% rule, I still manned to stay inside my weekly budget. My own reasoning was that at least it would be bang on. Dimensionally it’s got exactly what it needs but could do with some cosmetics, but using that extra thinking wasn’t necessary. I had been using a basic island in testing and tried Astra to remodel it on medium, which it did in less than an hour, and I realised I could have saved a shit load of time if I’d got it to do the plane as well, and it may have looked a bit better as well. I did that on the plus plan but I was lucky and had 3 resets saved up (since I had such a positive experience with Astra but it’s a bit more expense, I upgraded to the 100 plan on GPT and there’s no 5 HR limit which is brilliant, and I may get it to redo a couple of things aesthetically). The big problem now is as there’s so much bloody data, it means there’s lots of things you need to look at and putting them on both mobile and desktop was tricky and may not even be the best just yet. I intend on scaling it back for use for teachers but I did get a bit carried away trying to find my own answers which led to more things being added. I think there’s enough here to make a pretty solid judgment on what happened, purely from my own perspective. I absolutely love puzzles when you have lots of data but it’s all over the place and hard to visualise mentally if even with just images, needing to see it interact really helps me. I love that we can now do all this. It’s awesome. Anyway, thanks for reading, if you did. submitted by /u/ThePromptfather

Originally posted by u/ThePromptfather on r/ClaudeCode