I = Height of headstay termination above the sheer line.
J = Distance between the headstay termination at the deck and the front of the mast at the sheer line.
P = Distance between black bands on the mast, or the maximum luff length of the main.
E = Distance between black bands on the boom, or the maximum foot length of the main.
PY & EY are similar to P & E, but indicate mizzen dimensions.