Defeating a Bar Lodos

I've been having trouble completing a certain Braver quest that asks me to solo Coast Exploration with Azanami as my only partner, and do so on Super Hard and get an S ranking. Ok so the problem is that Bar Lodos, the boss, has this one attack that produces a large slow moving plasma ball type thing that decends onto the deck and eventually bursts, killing me without fail each and every time he chooses to do it. When he's low on health and in desperation mode, he can even choose to do it back to back... and I only have one 1/2 Scape to burn.

So, is there a way to avoid being killed by this move? I've tried a great many things but it seems it cannot be destroyed, and its burst range is the entire deck so it cannot be avoided either. 100% damage and a certain death to me whenever he fires it. What am I missing? Please and thank you.

There's a cannon on the back end of the raft. When he shows up to do the move, hit him in the face with the cannon's shot and he'll fall down stunned. Kill him.

On SH, the best time to harpoon him is actually near the beginning of the fight. He will start off by coming right up to the one of the sides of the raft and will then begin to fall behind it while lowering his altitude; if you don't attack him right away and are waiting in the harpoon instead, with your reticle just below his body, you can hook him just as he begins to fall behind the raft and his face passes your reticle:

To actually answer the question, you can break the giant water ball by hitting it with the turrets; you need to be in the turret before he unleashes the attack, preferable one of the two by the harpoon since they will require the least aim adjustment, and concentrate fire on the center of the ball, never letting go of the fire button. It could take a bit of practice to get the timing just right, but once you do, you'll never have to worry about it again.

You want to harpoon him after he does the shower-of-water-balls attack that he does, where he comes from afar, behind the craft. He'll then emerge up close, and when he stops moving, you harpoon him, and DPS him as hard as you can. However, he'll do the giant ball-of-water attack when he recovers. If he does this, RUN TO ONE OF THE TURRETS AND GET TO SHOOTING. If he starts charging, even with the harpoon ready, you won't be able to chain him down, so when you see him charging that attack, run to a turret and start firing. When the ball of water starts moving, FOCUS YOUR FIRE ON IT. It seems to be proportionate based on how many people are there, so if everybody present is shooting the ball with a turret, it will pop, and you won't get wiped.