43. Each float referred to in Byelaw 42 shall have clearly and legibly painted or otherwise fixed thereon in figures of not less than 12 centimetres in height such number as the Board may allocate to the licence-holder (or such number as the Board may allocate to the net or row of nets of which the float shall be a mark) and at all times when the net or row of nets is in use such number shall be clearly legible.