Shallowest Major Atlantic–Pacific Connections: Panama Canal, Gibraltar, Malacca

Critical Choke Points With Depth Limits

Three major waterways link the Atlantic and Pacific (or its marginal seas). Their shallowest controlling depths dictate maximum ship size:

1. Panama Canal (Atlantic ↔ Pacific Direct)

• Length: 77 km (48 mi)
• Minimum depth: 12.8 m (42 ft) (original locks); 18.3 m (60 ft) (Neopanamax locks, 2016).
• Limiting dimensions (Neopanamax): 366 m LOA × 49 m beam × 15.2 m draft.
• Significance: Only direct ocean-to-ocean canal; 6% of world trade.

2. Strait of Gibraltar (Atlantic ↔ Mediterranean → Suez → Indian Ocean → Pacific)

• Minimum depth: ~300 m (984 ft) at Camarinal Sill (main sill); much deeper elsewhere.
• Not a depth constraint for any surface ship (max draft ~25 m). Limits submarines (stealth depth) and internal wave dynamics.
• Strategic choke: 14 km wide; 100,000+ transits/year.

3. Strait of Malacca (Indian Ocean ↔ Pacific / South China Sea)

• Minimum depth: 25 m (82 ft) in the Phillips Channel (narrowest, shallowest section near Singapore).
• Malaccamax limits: 400 m LOA × 60 m beam × 20.5 m draft (300,000 DWT tankers).
• Busiest strait: ~90,000 vessels/year; 25% of world trade.

Comparison

Panama Canal is the shallowest engineered connection; Malacca is the shallowest natural strait on the primary Asia–Europe–Americas route.