I was almost certain, but I looked it up in MW, anyway - and there it was.

http://www.merriam-webster.com/dictionary/hatchman

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Note added at 1 hr (2014-09-11 21:54:51 GMT)
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And here:
http://tinyurl.com/n4vxkq2

And here:
In submission, the Maritime Union of Australia (MUA)11 advised that a hatchman overseeing work in the hold may have prevented the accident through an early alert to the team leader.12 The MUA considers that a hatchman was required and the lack of one was a critical weakness because the focus of the hatchman is the wellbeing of the workers in the hold.
Source:http://tinyurl.com/l344m8c

Nautical terminology:
Union Purchase: Two ships derricks linked together by a Union Plate,sometimes known as a "monkeys Face". One derrick is positioned directly over the cargo hold/hatch and secured by guys and preventers, and the other derrick is positioned over the side also secured by guys and preventers. The runners (lifting wire) of each derrick are then shackled to the Union plate. The union plate is a triangled plate with three holes,finally the cargo hook is then shackled in the third hole, so now the two derricks are joined together acting as one lifting unit . Now the ship is able to load or unload cargo with the aid of a winch driver for each derrick and a Hatchman. The Hatchman giving hand signals for the winch drivers to hoist or lower. When the lift is in sight, the two winchmen can swing the load over the hatch or ships side by their own driving skills.


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Note added at 1 hr (2014-09-11 22:00:32 GMT)
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And another:
http://www.longshoreshippingnews.com/2010/10/unions-express-...