The radial line on a radar set inscribed on a transparent disk which can be rotated manually about an axis coincident with the center of the PPI. It is used for bearing determination. Also called MECHANICAL BEARING CURSOR.

Related Terms

RESTRICTOR

A device for producing a deliberate pressure drop or resistance in a line by reducing the cross-sectional flow area.

TRAILBOARD

A decorative board at the bow of a vessel, sometimes bearing the vessel's name.

BALL BEARING

An anti-friction rolling type bearing containing rolling elements in the form of balls.

JOURNAL BEARING

A sliding type of bearing having either rotating or oscillatory motion and in conjunction with which a journal operates. In a full or sleeve type journal bearing, the bearing surface is 360° in extent. In a partial bearing, the bearing surface is less than 360° in extent, i.e., 150°, 120°, etc.

BEARING

A support or guide by means of which a moving part such as a shaft or axle is positioned with respect to the other parts of a mechanism.

GRID RHUMB LINE

A line making the same oblique angle with all grid meridians. Grid parallels and meridians may be considered special cases of the grid rhumb line.

HORIZON SYSTEM OF COORDINATES

A set of celestial coordinates based on the celestial horizon as the primary great circle; usually altitude and azimuth or azimuth angle.

HAND LEAD

A light sounding lead (7 to 14 pounds), usually having a line of not more than 25 fathoms

GROUND LOG

A device for determining the course and speed over the ground in shallow water consisting of a lead or weight attached to a line. The lead is thrown overboard and allowed to rest on the bottom. The course over ground is indicated by the direction the line tends and the speed by the amount of line paid out in a unit of time.

False brinelling

False brinelling of needle roller bearings is actually a fretting corrosion of the surface since the rollers are the I.D. of the bearing. Although its appearance is similar to that of brinelling, false brinelling is characterized by attrition of the steel, and the load on the bearing is less than that required to produce the resulting impression. It is the result of a combination of mechanical and chemical action that is not completely understood, and occurs when a small relative motion or vibration is accompanied by some loading, in the presence of oxygen.

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