Roughly a fifth of the world's seaborne oil passes through a handful of narrow straits — the Strait of Hormuz, Bab-el-Mandeb, the Turkish Straits, the Strait of Malacca. Each has a hard capacity ceiling set by channel width and safe-passage rules, so a partial blockage does not just delay a few ships — it caps how much can physically move per day. This 2D map looks straight down on the channel: drag to pan, scroll/pinch to zoom, and the strip chart below tracks throughput and price over time.
C_eff = C_max · (1 − disruption)
S = min(D, C_eff + R) (R = reroute capacity, only if rerouting is on)
R_max = 0.5 · C_max (a detour can carry at most half the strait's nominal flow)
The price reaction uses a constant price-elasticity-of-demand model. Short-run oil demand is famously inelastic (ε ≈ 0.1) — people and industry can't cut consumption quickly — so even a modest physical shortfall produces an outsized price move:
shortfall f = (D − S) / S
Price index = 100 · (1 + f / ε), ε = 0.1
→ a 20% supply shortfall alone implies a ~300% price index
Transit delay blends the two routes by their share of actual flow — the direct route picks up queueing delay as it nears saturation, the detour adds a fixed number of extra sailing days for the longer distance:
queue_days = 6 · max(0, (D − C_eff) / C_eff)
delay = [S_through·(8 + queue_days) + S_reroute·(8 + 14)] / S
- Strait capacity — the chokepoint's nominal daily throughput before any disruption.
- Disruption severity — how much of that capacity is knocked out (attack, grounding, political closure); the red gate across the channel fills in with severity.
- Global demand — how much oil the world wants moved through this route each day; when it exceeds effective capacity, tankers crawl and the unmet-demand bar at the origin hub climbs.
- Reroute around blockage — sends the overflow on the long detour (the dashed arc around the cape) instead of leaving it unmet; it always costs extra time, never extra capacity beyond R_max.
Real-world relevance: this is the mechanism behind oil-price spikes during Hormuz tension, Red Sea shipping attacks and Suez/Panama disruptions — a small physical capacity cut, filtered through inelastic demand, becomes a large price shock.