Ship is related to Sail. Sail is a synonym of Cruise. 
Back is a type of Strengthen. Back is related to Future. Future is a different concept from Past. Past is related to Feed. 
Ship <--RelatedTo--> Sail <--Synonym--> Cruise 
Strengthen <--IsA-- Back <--RelatedTo--> Future <--DistinctFrom--> Past <--RelatedTo--> Feed 