In "The Seafarer," I do not get the sense that fate drives the seaman as much as the call of his heart and his mind, so I would suggest that his heart and mind are stronger than fate.

If one is uncertain that one can separate heart and mind, consider the anonymous author's words:

But there isn't a man on earth so proud,
So born in greatness, so bold with his youth,
Grown so grave, or so graced by God,
That he feels no fear as the sails unfurl,
Wondering what Fate has willed and will do. (39-43)

It appears that the narrator is influenced both by pagan sentiments and Christian beliefs in that he refers to God and to Fate. It is not uncommon in what little Anglo-Saxon poetry survives (as seen with, for example, Beowulf), to see references to a mixture of the belief systems of two separate cultures as they were in the process of being blended together. "God" and "Fate" are both capitalized, signifying the importance of both, but "Fate" is also personified as a sentient force.

In the passage above, the speaker embraces the importance of God's power (God has shown him such "grace") while also fearing the influence Fate will play in his life.

At the same time, he experiences a fierce desire to pursue a life at sea even though it is a lonely and harsh existence that those living on solid ground cannot appreciate. He is inexorably drawn to the freedom and beauty of the ocean:

And yet my heart wanders away,
My soul roams with the sea, the wales'
Home, wandering to the wildest corners
Of the world, returning ravenous with desire,
Flying solitary, screaming, exciting me
To the open ocean, breaking oaths
On the curve of a wave. (58-64)

Are not the lives of people today much the same as this man who lived so many, many years ago? Even in modern times, life presents us with paradoxes we so often attempt to understand. For instance, the seaman bewails and even hates his harsh existence on the sea, but, at the same time, he finds purpose and an inability to stay away ("ravenous with desire," line 61). He believes that God watches over him, but the sailor also fears the capricious control of Fate. In light of all that he faces (he even recognizes the powers around him that he is certain he cannot control) the seafarer still follows his heart and mind, choosing to give in to the sea's siren call.

Personally, I do not believe in fate. I recognize the choices each person makes in his or her life that govern the paths that person will take, and therefore, the kind of life he or she will lead. I do not struggle with fate, but have faith in God. Even in light of this distinction, I believe that all people make decisions that shape their experiences in the world. For me, I am convinced that neither predestination nor fate controls me. Instead my choices affect the life I lead; I create the road by my decisions. Personally, I believe that man's heart and mind are stronger than fate, and I feel the seafarer also believes this. 

Remember that in this poem, the author was hanging in the balance between paganism (and the belief in Fate) and Christianity (where Fate doesn't exist, only the master plan of God).

The speaker of the poem is saying that Fate is stronger than any man's mind since he could have chosen the pleasurable and easy life on land, but went with his deepest desires instead.  He returns to the sea, where he will most likely be hungry, cold, and exhausted much of the time, but happier than he would be on land since he loves the life on the sea.  You see, it is his fate to be at sea...not to live a life of luxury and comfort on land.

This question relates to an 'age-old' philosophical question - can we change the future? are you confined by your destiny? can you change your fate?

Remember that this poem was 'adapted' for a Christian audience from the original Pagan version. The line of the poem "fate is stronger/... than any man's mind? " tells the reader that God (or gods) are omnipotent, solely determining your unchangeable fate.

The Seafarer may be a exemplum - that is, a piece of writing written for the purpose of 'lecturing' the audience on particular point - here focused on the Anglo-Saxon belief that Fate controls mortal lives. And then reinforcing that the Christian God is also all-powerful.

Indeed "Fate" appears as a character in the poem - as if Fate just decides to give sickness, war or death to people in a haphazard fashion. 

In order to answer the question "do you agree", you will need to look at your own beliefs and faith. Do random events control the flow of your life, or a God (or gods), or are you in control of your life plan? 

Chances are your answer will include a mixture of 'yes/no' points. For example: if you work hard you'll get better grades, but some people are naturally better at some school subjects. Or, if you're hit by a car, is that the fault of 'God' or just bad luck?