Retreat is a type of Withdrawal. Withdrawal is derived from Withdraw. Withdraw is a type of Travel. Boat can be used for Travel. 
you are likely to find Landing in/at/on Ocean. Ocean is related to Island. Island is a type of Book. 
Retreat --IsA--> Withdrawal --DerivedFrom--> Withdraw --IsA--> Travel <--UsedFor-- Boat 
Landing --AtLocation--> Ocean <--RelatedTo--> Island --IsA--> Book 