Manufacturer: National Oilwell
Model: 80B
Type: Mechanical Drawworks
Application: Workover & light drilling rigs
The National 80B Drawworks is a compact, rugged mechanical drawworks designed for light to medium duty hoisting. It is well known for its simple design, reliability, and ease of maintenance, making it popular on workover rigs, shallow drilling rigs, and service rigs.
Drum Diameter: ~24 in
Drum Length: ~36 in
Drum Type: Single drum, grooved
Main Shaft Diameter: ~6 in
Frame: Cast steel construction
Rated Input Power:
300–400 HP (varies by gearing and brake configuration)
Drive Type:
Chain drive or compound drive
Clutches:
Air-operated friction clutches
Fast Line Pull: ~30,000 – 40,000 lb
Maximum Hook Load: ~150,000 – 200,000 lb (depending on line size & reeving)
Drilling Line Size:
⅞ in – 1 in wire rope (typical)
Primary Brake: Mechanical band brake
Auxiliary Brake:
Hydromatic brake (optional / common upgrade)
Emergency Brake: Manual band brake
Number of Speeds: 3–4 forward speeds + reverse
Gear Type: Spur / helical gears
Lubrication: Splash lubrication