Helmsman Linear Units

Mmi – One thousandth of an iral.
Thumb = One Tenth the length of a Human Foot (see below).
Iral = derived from ancient measurements of an “average” human foot.
C’lenyt = 5,500 irals.

Helmsman Units of Mass

Stoneweight = 1/2000 of a Millston.
Milston = Mass of approximately one Standard Mill Stone (see Imperial Museum, Avalon).

Helmsman Surface Directions

Lightward = Facing planetary rotation.
Nightward = Opposite direction from planetary rotation.
Boreal = Left-hand planetary pole, facing Lightward.
Austral = Right-hand planetary pole, facing Lightward.