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"fiddley"
definition, perhaps from "The Oxford Companion to Ships and the Sea"
fiddley, a raised deck grating fixed over the hatches above the engine rooms of steam- or early diesel-powered vessels to let the hot air and fumes escape. Fresh air would enter the engine room through the ventilators and force the hot air out through the fiddleys. In rough weather they were made watertight by tarpaulins spread over them and secured by battens.
