Four frontier models raced a sailing sim Claude Code built — Gemini 4 Argon won
A Reddit user built a 3D sailing simulator with Claude Code, then let Gemini 4 Argon, GPT-6 Astra, Claude Opus 5.5 and Qwen3.5-9B race the same course. Argon won — at a fifth of the cost of its nearest rival — but the thread itself is the first to say this was a fun experiment, not a benchmark.
- The race: four models, one course, the same wind, 30× speed; every 5 seconds each model received the full state — 23 numbers covering heading, wind, position and more.
- The result: Gemini 4 Argon won; the thread's summary puts it at about a fifth of GPT-6 Astra's cost. Opus 5.5 struggled; Qwen3.5-9B stalled.
- The builder: Reddit user abhi3188, who says Claude Code wrote 'basically all' of the simulator.
- Traction: about 1,300 upvotes and 128 comments on r/ClaudeAI within eleven hours; the author has since posted follow-up runs with DeepSeek, Kimi and Fable.
The newest frontier-model comparison didn't come from a lab. It came from a sailing simulator one Reddit user built with Claude Code — and a 37-second video of four AI models racing the same course in the same wind. Gemini 4 Argon won. The twist the thread keeps coming back to: the model that built the game, Claude Opus 5.5, was the one that couldn't sail it.
The post, by u/abhi3188 on r/ClaudeAI, gathered about 1,300 upvotes and 128 comments within eleven hours. It is the kind of community experiment that spreads because it is watchable — and because the result is genuinely surprising. It is also, as the thread itself is quick to point out, a single run with loose rules. The honest way to read it is as a demo with a real signal inside, not a leaderboard.
Watch the race: the 37-second video is in the original thread on r/ClaudeAI — here.
I built a sailing sim with Claude Code and made the frontier models race each other in it
by u/abhi3188 in ClaudeAI
The race#
The setup is simple, which is part of the appeal. Claude Code wrote what the author describes as basically all of the simulator: the boat physics, the wind model, the 3D water. Every five seconds, each model receives the full state of its boat — 23 raw numbers covering heading, wind, position and more — and decides what to do next. Four boats, one course, the same wind, fifteen minutes of race clock compressed to 37 seconds at 30× speed.
The finishing order, as the thread's own summary tells it:
| Model | Result |
|---|---|
| Gemini 4 Argon | Won the race — and, per the thread's summary, at about a fifth of GPT-6 Astra's cost |
| GPT-6 Astra | Behind Argon on time and, per the same summary, about five times the cost |
| Claude Opus 5.5 | Struggled badly — despite Claude Code having built the simulator it was racing in |
| Qwen3.5-9B | Stalled early and drifted to the beach |
The Opus result is the one that made the thread. A commenter summed up the reaction: wild that Claude couldn't figure out a game created in Claude Code. The qualification, offered by another commenter and not disputed in the thread, is that the racing Opus instance had no context of having built the game — it started cold, like every other model. Still, the irony landed: the house model lost on its home course.
Why Argon won — the thread's theory#
The leading explanation in the comments is spatial reasoning. One commenter argued that Argon is unusually good at well-defined end-state tasks and that Google specifically trained it to be spatially aware — and suggested the Google Maps connection as the reason. The author replied that the theory made sense and that he hadn't considered it. Another commenter called Argon strange in exactly this way: it breaks on easy UI work but is strong on spatial tasks. A third said the result had them re-evaluating Argon for their own applications.
That is a theory, not a finding — one race cannot support it. But the cost point is the more interesting number if it holds up. A model winning a spatial task outright at a fifth of the price of its nearest rival is the kind of result that changes what people try next, and the thread's reaction suggests it did: several commenters said they were reconsidering Argon on the strength of a 37-second sailing video.
The caveats the thread raised itself#
To the thread's credit, it did its own peer review in the comments — and the caveats are substantial:
- One run. This was a single race, not a benchmark. Nothing here has been repeated, and nobody in the thread claims otherwise.
- Loose rules. The author confirmed he didn't have a clear enough rule for rounding a mark. One commenter questioned whether sailing dead downwind was optimal in the sim — which, if true, would reward a degenerate strategy rather than good sailing.
- Possible sim bugs. Another commenter raised the possibility that a boat had simply dropped anchor — a reminder that a surprising result in a homemade simulator can be a simulator bug, not a model gap.
- Uneven field. A commenter corrected the 'frontier' framing: Qwen3.5-9B is a 9-billion-parameter model, about nine months old — not a peer of the other three.
None of this kills the story; it scopes it. The result is a data point, not a verdict — one race, one course, one wind — and the thread knows it.
What to watch#
The author has already posted follow-up runs with DeepSeek, Kimi and Fable — more boats, more data points, the same caveats. What would make the next round convincing is repetition: the same course sailed several times, a fixed rule for rounding marks, and the wind held constant across runs.
The wider thing to watch is the genre itself. Community-built micro-benchmarks — cheap to run, fun to watch, peer-reviewed in the comments within hours — are becoming a real way frontier models get compared in public. They will never replace rigorous evals, and they shouldn't. But a 37-second video that makes a thousand people rethink a model is a signal worth noticing, even when the leaderboard it implies is only one race deep.
Sources: the original r/ClaudeAI thread by u/abhi3188, here; the race video is embedded above from the same thread. Cover photo: yachts racing at Cowes Week 2010, Editor5807, CC BY 3.0, via Wikimedia Commons. Second photo: a yacht under sail, jounigripen, CC BY 2.0, via Wikimedia Commons. Third image: AI-generated editorial illustration.