A family is in distress on an island.

They must come to shore.

A rowboat can only hold 90 kg.

They can not swim.

 Hints   : Dad weighs 85 kg.
                Mom weighs 65 kg.
                Son weighs 45 kg.
                Daughter weighs 40 kg.
                Dog weighs 8 kg.

Question: How do they get to shore?

See answer