Two Quadrants

Two nearly identical clinometers to measure the maximum inclination of a rolling ship. Both are made of brass, mounted on a wooden backplate with the center of the arc at the top. The scale on the arc runs from 0° to 45° to each side. The outer edge of the arc is toothed, each side in the opposite direction. The two pointers have pallets against the back, which engage in the teeth: this allows them to move only outward along the arc. The pallets can be released by hand to return the pointers to 0°. Due to a small interruption of the pallet edge, the pointers cannot end up in each other's eighth of the arc. The teeth of quadrant A divide the arc into quarter degrees, which on quadrant B are half degrees. The pointers on quadrant A run with small rollers over the protractor. If the ship rolled, each pointer would swing out to the side where the ship leaned and indicate the maximum inclination.