Nautilus International is a trade union and professional organisation representing more than 22,000 maritime professionals in ... the UK, Netherlands and Switzerland. Nautilus members work at sea and ashore. Sometimes we are referred to as the ‘Merchant Navy union’, but this doesn’t tell the whole story. Members include shipmasters, officers, cadets, ratings, yacht crew, VTS officers, harbourmasters, river boatmen, nautical college lecturers, maritime lawyers and even ship-based medical personnel. read more