u/EntertainmentOk7028

I was wiring a browser-side coursework checker and realized this one is easy to miss: Simpson's rule will integrate whatever step you give it.

If the heel step is 10 degrees and you use h = 10 instead of h = 0.1745 rad, every area comes out 57.3 times too large. The GZ curve still looks normal, so the mistake may only show up in the criteria table.

I put the hand-calculation chain and a small cross-checker on the MetaCAD site I'm building: ship stability coursework workflow.

It's for coursework and preliminary checks, not vessel operations. The page shows the substitutions instead of just returning pass/fail.

What other stability-assignment errors have you seen survive a quick visual check?

Put the long-term energy scale and the recent AIS series into one view.

EIA estimates that 20.9 million barrels/day of oil moved through Hormuz in the first half of 2025. That's roughly 26% of world maritime oil trade.

The recent vessel count then falls hard: IMF PortWatch averages 81.2 AIS-counted transits/day from 1 August 2025 to 28 February 2026, and 9.9/day from 1 March to 23 July - down 87.8%.

Big caveat, and it matters here: IEA says AIS in the Strait became especially unreliable after late February because of jamming, spoofing and ships going dark. So this is a collapse in visible AIS traffic, not proof that 88% of physical transits stopped.

Sources: EIA, IMF PortWatch, IEA. I made the graphic; the data is theirs.

Pulled the SCA annual figures and the newer PortWatch AIS series into one view.

Long-term: 11,751 transits in 1950, closed from June 1967 to June 1975, 26,434 in 2023, then 12,758 in 2025.

The odd bit is the last year. Split PortWatch at 28 February 2026 and both sides average 40.7 transits/day, through 26 July. So there isn't a fresh break visible after that date. Suez traffic was already sitting at the much lower post-2023 level.

Important caveat: the annual figures are official SCA counts; the recent comparison is AIS-derived and uses a different method. That's why they're shown as separate panels rather than one continuous series.

Sources: Suez Canal Authority, World Bank archive, IMF PortWatch. I made the graphic; the data is theirs.