Article 4 of the IBF Framework Agreement, containing the NSWC, reads
Neither seafarers nor anyone else on board whether in permanent or temporary employment by the Company shall carry out cargo handling services in a port, at a terminal or on board of a vessel, where dock workers, who are members of an ITF affiliated union, are providing the cargo handling services. Where there are not sufficient numbers of qualified dock workers available, the ship's crew may carry out the work provided that there is prior agreement of the ITF Dockers Union or ITF Unions concerned; and provided that the individual seafarers volunteer to carry out such duties; and those seafarers are qualified and adequately compensated for that work. For the purpose of this clause “cargo handling services” may include but is not limited to: loading, unloading, lashing, unlashing, checking and receiving.
Read the complete article here.