Is life compared to a boat? How do the men overload their 'boat of life'? How does it affect their nature in the long run?

Life is not so much compared with a boat but used as a symbol for how life should be lived. Check out the direct quote below.

“Let your boat of life be light, packed with only what you need - a homely home and simple pleasures, one or two friends, worth the name, someone to love and someone to love you, a cat, a dog, and a pipe or two, enough to eat and enough to wear, and a little more than enough to drink; for thirst is a dangerous thing. ”