State Compliance Guide
Every motorized vessel operated on Oklahoma public waters must display its OK-prefixed registration number on both sides of the forward half of the hull, along with the current state validation decal. Oklahoma enforces specific rules on letter height, font style, color contrast, separator spacing, and exactly where the validation decal sits relative to the number. The summary below covers the requirements most commonly missed during inspections.
Letters and numbers must be at least 3 inches tall, in plain block font with structural stroke width of at least 0.5 inches. Script, italic, shadowed, and outlined fonts are not acceptable. Stroke width should be heavy enough that the sequence reads cleanly from at least 100 feet away in daylight.
The number must be a color that sharply contrasts with the hull. Light hulls (white, cream, light gray) require dark letters; dark hulls require light letters. Reflective vinyl is permitted as long as the underlying contrast holds during the day.
Space or hyphen must separate the OK prefix, the digit group, and the suffix letters. Example: OK 1234 AB or OK-1234-AB. Running the characters together is a violation.
Aft (behind) and directly in line with the text block. The decal must be on both sides of the forward half of the hull and clearly visible from the side of the vessel.
Numbers go on both sides of the forward half of the vessel, above the waterline, in an unobstructed location, reading left to right. Anything that covers or partially obscures the sequence — rub rails, fenders, accessories — can cause an inspection failure.
At least 3 inches tall, measured from the top to the bottom of the character, in plain block font with structural stroke width of at least 0.5 inches.
No. Oklahoma requires plain, vertical block characters. Script, italic, shadowed, and outlined fonts are not compliant.
Aft (behind) and directly in line with the text block, on both sides of the forward half of the hull.
Space or hyphen. OK 1234 AB and OK-1234-AB are both acceptable; OK1234AB is not.
Specific font geometry rules enforce a thick 0.5-inch structural line thickness metric.
Our online designer enforces the 3-inch height, plain block font, and contrast rules automatically — so what you preview is what passes inspection.
Source: Reference · Always verify current requirements with your state boating authority before relying on this guide for compliance.
