Free Off the Mangrove Coast (Ss) (2000) by Louis L'amour

"When you get it out of the desk," he said, "just tie her on the line and give us a signal."
    But there was something about the way he said it that was wrong. As I started into the water, he leaned over suddenly and stroked his hand down my side. I thought he wanted something and turned my faceplate toward him, but he just stood there so I started down into the water.
    When I was on the deck of the freighter, I started along toward the superstructure and then saw something floating by my face. I stepped back to look and saw it was a gutted fish. An instant, I stood there staring, and then a dark shadow swung above me and I turned, stumbled, and fell just as the same huge shark of a few days before whipped by, jaws agape.
    On my feet, I stumbled toward the companionway, and half fell through the opening just as the shark twisted around and came back for another try.
    And then I knew why Limey Johnson had been fishing, and what he had rubbed on my arm as I went into the water. He had rubbed the blood and guts of the fish on my suit and then had dumped it into the water after me to attract the shark.
    Sheltered by the companionway, I rubbed a hand at my sleeve as far around as I could reach, trying to rub off some of the blood.
    Forcing myself to composure, I waited, thinking out the situation.
    Within the cabin to the right, I had already noticed the door of the desk compartment that held the cash box stood open to the water. That meant the money was already on our boat; it meant that the bumping I'd heard along the side had been the box as it was hoisted aboard.
    And letting me go down again, rubbing the blood and corruption on my sleeve had been a deliberate attempt at murder.
    Chug-chug-chug ... monotonously, reassuringly, the steady sound of the pump reached me. Smoke was still on the job, and I was still safe, yet how long could I remain so under the circumstances?
    If they had attempted to kill me they would certainly attempt to kill Smoke, and he could not properly defend himself, even strong as he was, while he had to keep at least one hand on the pump. Outside, the shark circled, just beyond the door frame.
    Working my way back into the passage, I fumbled in the cabin, looking for some sort of weapon. There was a fire ax on the bulkhead outside, but it was much too a clumsy for use against so agile a foe, even if I could strike hard enough underwater. There was nothing ... suddenly I saw on the wall, crossed with an African spear of some sort, a whaler's harpoon!
    Getting it down, I started back for the door, carefully freeing my lines from any obstructions. Chug... chug... chug...
    The pump slowed, almost stopped, then picked up slowly again, and then something floated in the water, falling slowly, turning over as I watched, something that looked like an autumn leaf, drifting slowly down, only much larger.
    Something with mouth agape, eyes wide, blood trailing a darkening streamer in the green water ... it was Long Jack, who had seen the last of Sydney ... Long Jack, floating slowly down, his belly slashed and an arm cut across the biceps by a razor-edged knife.
    An instant I saw him, and then there was a gigantic swirl in the water, the shark turning, doubling back over, and hurling himself at the body with unbelievable ferocity. It was my only chance; I stepped out of the door and signaled to go up.
    There was no response, only the chug-chug-chug of the pump. Closing my valve only a little, I started to rise, but desperately as I tried, I could not turn myself to watch the shark. Expecting at any moment that he would see me and attack, I drifted slowly up.
    Suddenly the ladder hung just above me although the hull was still a dark shadow. I caught the lower step and pulled myself slowly up until I could get my clumsy feet on the step. Climbing carefully, waiting from moment to moment, I got to the surface and climbed out.
    Hands fumbled at the helmet. I heard the wrench, and then the helmet was lifted off.
    Smoke