 In <unk> Shetland came under nominal Scottish control , although the Norse ' <unk> of Norway ' kept their Papa <unk> estates until the 17th century . In the 16th century merchants from <unk> and Hamburg were operating a summer trading booth to buy fish from the local fleet . By the 18th century , two Scottish <unk> , Thomas <unk> of <unk> , and Arthur <unk> of <unk> , owned the island . They maintained a prosperous <unk> ( Old Norse : ' deep sea ' ) fishing industry , undertaken in the summer months using six @-@ <unk> boats known as <unk> . 
