1945 U.S. Navy Parallel Motion Protractor With Wooden Case. Comes with everything seen in the images. The wooden case is approx 23 5/8" x 13" x 4 1/2" and it weighs 18.5lbs. By the B.K. Elliot Company. The protractor is in a good, vintage condition with signs of wear. The wooden case also has some heavy wear. Please see the images as they are part of the description. Parallel Motion Protractor (PMP) is a valuable tool for plotting direction quickly and accurately. When in restricted waters and plotting fixes every 3 minutes, you will greatly appreciate this instrument. The PMP is usually anchored to the top of the chart table. The PMP is designed to keep the moveable compass rose oriented to the longitude and latitude of any chart. An arm is attached to the moveable compass rose which can be rotated to whatever bearing you require and then moved to the object on the chart that the bearing was taken to, so a LOP can be drawn.