If you want to become a full crew member, you must get a certificate after training. Ordinary crew members must take the basic safety and raft training examination (four certificates), and can apply for other certificates such as crew certificate and service book only after passing the examination. If you are a crew member on duty, such as a mechanic or a sailor on duty, you must also take the corresponding level of duty certificate training exam. Officers also need other training, such as advanced fire fighting, skilled first aid, medical treatment, radar, security and so on. Tankers, chemicals and passenger ships all have special certificates.