Orphan et all,

Stolen from F18 rules:
C.3 CREW
C.3.1 MEMBERSHIP
a) Crews are not permitted to enter a Formula 18 event unless they are current members of their NCA.
b) In countries where there is no NCA, the crew shall be member of the IF18CA.
C.3.2 LIMITATIONS
(a) The crew shall consist of 2 persons.
(b) The crew shall use the sails (as defined in G.2.3) in accordance with the following weight categories:
(1) Crew between 115 kg and 130 kg shall sail with the small jib and small spinnaker and then shall carry extra weight equal to half the difference between their actual weight and 130 kg.
(2) Crew between 130 kg and 140 kg shall sail with the small jib and the small spinnaker and shall not carry extra weight.
(3) Crew in between 140 kg and 150 kg may use the large jib and the large spinnaker and then shall carry extra weight equal to half the difference between their actual weight and 150 kg. International Formula 18 Class Rules 2010 9
(4) Crew weighing 150 kg and over may use the large jib and the large spinnaker without carrying any extra weight.
C.3.3 WEIGHTS
(a) The minimum combined crew weight is 115 kg
(b) They are four categories of crew weight:
(1) from 115 kg to less than 130 kg
(2) from 130 kg to 140 kg
(3) from 140 kg to 150 kg
(4) above 150 kg
(c) Crew corrector weights shall be of metal and securely fastened on the port side, either to the outside of the front crossbeam or to the strut, , and shall be removable for checking.