Definitions #
The vertical distance between the waterline and the bottom of the hull (keel), indicating how deep a ship sits in the water.
Technical The ship's vertical immersion, measured in meters or feet, typically ahead (forward draft) and aft (stern draft), which determines under-keel clearance and max permissible cargo load in a given berth or fairway.
Etymology #
From Old English dragan (to draw or pull), related to 'drawing' water; in that sense, the depth to which something is pulled down into the water.
Collocations #
- air draft 水面以上高度（从水线到船舶最高点），用于桥梁或架空管线限制
- draft survey 水尺检量，通过读取船舶吃水估算装载货物重量
- maximum draft 最大吃水深度，表明船舶允许的最大载重吃水
Real Business Examples #
- The vessel failed to berth at the Port of Shanghai because its draft exceeded the channel depth during low tide.
- According to the draft survey, the cargo loaded was 8,500 metric tons.
Register & Variants #
- Register: formal
- BrE/AmE: 'Draft' 为美式，英式传统拼法为 'draught'，行业海事环境均通用
Synonyms & Antonyms #
- Synonyms: draught, immersion depth
Common Errors #
- Confusing draft with depth of the waterway. Draft is a ship's requirement; water depth determines safe clearance. For safe navigation, the draft must be less than the available navigable depth plus under-keel clearance.
- Using air draft interchangeably with draft when checking bridge clearance. Draft is below waterline; air draft is above. For bridge or cable restrictions, use the air draft calculation, not the draft.
Confusable Terms #
- under-keel clearance (UKC) vs Draft
- UKC is the gap between the keel and the seabed/channel bottom, whereas draft is the vertical depth of the hull submerged.
Frequently Asked Questions
What is a safe draft margin for a container ship entering a port??
Usually ports specify a required UKC—often 1-2 meters or 10% of draft—but this depends on local regulations, wave conditions, and vessel type.
How is draft measured when a ship is loaded at terminal??
By reading the draft marks (Plimsoll marks not needed; draft marks at bow, amidships, and stern) on both port and starboard sides, then applying a correction for water density.
Published: 2026-09-25 Category: Shipping