Getting here from "MAIN DECK"

WWII  LIBERTY  SHIP  -   S. S.  Jeremiah O'Brien 

"When you order a hard over rudder, a good helmsman will take it to 35 degrees.  The other 90% will put it into the stops at 36 or 37 degrees and risk jamming it for no effective gain in turning effort.

The normal navy rudder orders are (example) right standard rudder (15 degrees), right full rudder (30 degrees), hard right (35 degrees).

The merchant marine way is to give direct orders: right 10 degrees rudder, right 30 degrees rudder, hard right.

I found that using right 10 and right 20 were better than the 15 degree increments.  When I had a tanker alongside and I was maneuvering on station (consoling), when we finished, I would order right 10 degrees and it would open the bow gently away but hold the stern exactly at the distance we had been working (140').  I would start my swing away, then ring up a full bell and away we'd go.  Using a 20 degree rudder as you approach a dock gives the bow a good swing, fast and bleeds speed off from water resistance.  It really shows when you are playing with just a few feet of distance.  That is captain experience talking, not ensign or jg speak.  They haven't been through the fire yet." Capt. Patrick Moloney

Click image for LARGER VIEW


You can see the degree markings on the "QUADRANT GEAR" above.  [ a 1/4 circle frame fixed to the head of a ship’s rudder ]
"A" - Steam Exhaust line – it’s lagged "F" - Rudder Angle indicator input
"B" - Pinion Gear, turns quadrant.  The big gear under it is turned
          by a worm gear on steering engine crankshaft. Note below
"G" - Manual centering tackle. If power is lost you can
          move the rudder with ropes and pulleys.
Note below
"C" - 20 degree mark, then 30, 33 and
          last by the red is 40 deg.
"H" - Red devil blower stowed out of the way. 
          Left there last time the compartment was painted.
"D" - Support for Tiller "7" - Step Ladder, temporary stowed.
"E" - Wood crush block View: DESCRIPTION by Historic Naval Ship Association
"B" The bearing to right supports the weight of the quadrant.
"G" The big block & tackle is for in case the steering engine is completely shot, you can rig it to the quadrant and
 up through soft patches in the main  deck and haul the rudder to midship using the warping winch behind #5 hatch. 
You can't steer with it, just pull the rudder to towing position.
Capt. Patrick Moloney

  Looking FORWARD

"A" - ENTRY HATCH to small arms magazine. 
         The door to the right is 5” ammo magazine
"G" - top pinion gear attached to larger bull gear under it.
Turned by a  worm gear on the steering engine crank shaft
"B"Steam Exhaust line "H"input to telemotor controlled from the bridge (hydraulic)
"C"Steam Supply to steering engine "J" -  Beige piping is hydraulics for TELEMOTOR.  the grey line is the
grounding wire to the top of the rudder post 
"D" - Steering Control valve "L"SHOCK absorber................................................................
"E"Steam Engine shrouding "M"red pin is the key holding the rudder post to
           the quadrant (gear)
"F" -  Rods from engine to worm gear. ........................... "N"rudder stock pin for hoisting rudder internally

 Looking to STERN

"A" - LADDER to the fantail. Emergency escape and use to pass lines up

"E" - Spare rudder shock absorber

"B" - Manual Tackle for centering rudder if steering engine OOC's

"F" - Pipe stanchion (structural support)

"C" - Spare mooring lines

"G" - Afterpeak tank vent line

"D" - Grounding wire for rudder to hull (probably from degaussing syst)