Posted by Scott Andrews on September 20, 1998 at 00:18:15 in spider-wj084.proxy.aol.com:
In Reply to: Forecastle Steam Valves posted by Bob Read on September 19, 1998 at 13:45:39:
Bob,
Those two extra wheels are the on-deck
controls which operate the braking mechanisms
of the anchor windlasses. On page 123 of Bob
ballard's book (fold out mosaic) the two hand
wheels atop their gear boxes can be seen
along with the shafting (pipe-like structures)
which connects them to the windlass brakes.
In the same book on page 97 in the upper left
corner of the large photo of the wreck, you will
see the universal joint of the shaft on the port
windlass. On the handwheel shaft, inside the
gear box, is a worm gear which turns a spur gear
on the shaft going to the windlass. This shaft
tightens a brake band around a drum keyed to
the windlass shaft underneath the large bed
plate of the windlass gear. The brake is used to
let go the anchor and as part of the gear to hold
it in place when weighed (the hoop-like objects
at the end of the chain rails in the photo just
above this one would also be cranked down
with the short handwheels seen next to them
when at sea, clamping down on the anchor
chains, and as an additional measure, chain
nippers (the small chains that pass through the
anchor chains in that photo) would also be put
in place. The same type of brake mechanism
is still used on windlasses and winches today.
For those of you familiar with antique autos,
this type of brake looks and works similar to the
external contracting type brakes used on autos
built from about the turn of the century on into
the mid-20's, prior to the adoption of the internal
expanding type we still use on drum brakes.
Regards,
Scott