Rocket Gibraltar (1988) on Netflix

Plot summary

Levi Rockwell is a widowed, retired Hollywood screenwriter who lives on a Long Island estate, and he calls the whole family home to mark his 77th birthday. His four children, Rolo, Rose, Ruby and Aggie, arrive with families of their own. Levi gets on best with his youngest grandchild, Blue, who notices a scale model of a Viking ship in the house. Blue and his older cousins talk over what to give their grandfather, and on a bike ride they spot an abandoned boat sitting in the grass. They choose to fix it up as his gift while the grown-ups stay absorbed in their own worries.