Converting Entity Relation(ER) Model to Relational Schema?

I have the following ER Model

I am trying to convert this to a relational database schema but I am not sure about several things:

1. PORT_VISIT and PORT are weak entities. How do I figure on which strong entities they are dependent upon ? Usually, this would be easy in a binary relationship but the ternary relationship SHIP_AT_PORT is confusing me.


2. SHIP and PORT are related by N to 1 relationship HOME_PORT. With the relational schema, the usual idea is to put in the entity close to the N (SHIP in this case) as a foreign key the primary key of the 1 entity( PORT). But PORT in this case is a weak entity, so do I use the partial key ?

If anyone can answer these questions and/or show me relational schema, I would be highly appreciative. Thanks !