ASTM F906-85(2003)

1.1 This specification specifies shape, size, spacing, and shading of letters and numerals to be used aboard ship.

1.2 Characters are of Five Types:

1.2.1 Type 1 – Plain letters and numerals (16 units).

1.2.2 Type 2 – Block letters and numerals (12 units).

1.2.3 Type 3 – Type 2 characters with shading (shading – 1 unit).

1.2.4 Type 4 – Block letters (10 units) and numerals (12 units).

1.2.5 Type 5 – Type 4 characters with shading (shading – 1 unit).

1.3 This specification does not give location or size of various shipboard markings incorporating letters and numerals.