Cracks start at square corners: make corners round!
Technical instruction sheet: a small ship silhouette is magnified in a red circle to show a crack running from a square corner, with a diagram and formula for how round to make corners. It presents a single engineering fact plainly. The persuasive element is the visual link from one crack to a whole ship; no emotional technique is strongly present.
Propaganda techniques used in this poster
- Date
- 1944
- Period
- Second World War
- Made by
- U.S. Navy Department, Bureau of Ships
- Region
- North America
- Country
- United States
- Medium
- Poster
- Issuer type
- Military
- Regime
- Roosevelt Administration
- Leader
- Franklin D. Roosevelt
- Audience
- Own forces
- Purpose
- Warn or inform
- Themes
- War and the military, Science and technology
- Event
- World War II
- Regime
- Roosevelt administration
- Leader
- Franklin D. Roosevelt
- Source
- Identified Openly sourced: the speaker is who they say they are
- Source
- U.S. National Archives and Records Administration, Record Group 44, World War II Posters, retrieved October 4, 2026
- Rights
- Public domain (U.S. government work)
U.S. Navy Department, Bureau of Ships. National Archives and Records Administration, RG 44, 44-PA-614 (NAID 514092).
Text on the object
CRACKS START AT SQUARE CORNERS MAKE CORNERS ROUND! HOW ROUND? r S W S WHERE r = RADIUS OF CORNER S = DIRECTION OF PRINCIPLE STRESS W = WIDTH (PERPENDICULAR TO STRESS) THEN r SHOULD BE NOT LESS THAN 1/8 W - AND PREFER- ABLY 1/4 W [imprint: NAVY DEPARTMENT, BUREAU OF SHIPS APRIL 1, 1944] [imprint: PRINTING OFFICE 1944-O-581666]
