| 1 | Derrick Main Legs | Carry the primary compressive and lateral loads of the derrick structure. | Four-leg lattice frame; height commonly selected according to required setback, racking capacity, and mast configuration. | Welded structural alloy steel, typically supplied with documented mill certificates. | Rated hook load, wind loading, fatigue resistance, buckling control, weld quality, and corrosion protection. | API Spec 4F; ISO 13535; applicable structural steel and welding codes. |
| 2 | Mast Sections | Provide a transportable, telescoping, or jackknife support for the crown and hoisting system. | Two- or three-section design; generally assembled with pinned or bolted connections for field erection. | High-strength low-alloy steel or quenched-and-tempered structural steel. | Erection sequence, transport dimensions, connection tolerances, dynamic loads, and wind stability. | API Spec 4F; API RP 54; ISO 13535. |
| 3 | Crown Block Support Frame | Supports the crown block and transfers hoisting loads into the derrick or mast. | Reinforced top frame with load-bearing beams, gussets, inspection platforms, and tie-in points. | Structural carbon or alloy steel with wear-resistant connection hardware. | Concentrated sheave loads, impact factors, alignment, access for maintenance, and platform safety. | API Spec 4F; API Spec 8C for hoisting equipment interfaces. |
| 4 | Crown Block and Sheave Assembly | Redirects and supports the drilling line during raising, lowering, and suspended-load operations. | Multiple grooved sheaves sized for the drilling line diameter and the required line arrangement. | Forged or cast alloy-steel sheaves; steel frame; sealed or lubricated bearings. | Sheave-to-rope diameter ratio, bearing load, groove profile, guarding, braking loads, and inspection access. | API Spec 8C; API RP 9B; applicable wire-rope inspection requirements. |
| 5 | Monkey Board and Racking Platform | Provides an elevated work position for pipe handling and organizes tubulars in the setback area. | Tubular racking capacity commonly specified by pipe size, setback load, and fingerboard arrangement. | Structural steel grating, tubular frames, impact-resistant pipe guides, and safety barriers. | Rated setback load, slip resistance, fall protection, ergonomic access, drainage, and tubular retention. | API Spec 4F; OSHA or equivalent local occupational-safety requirements. |
| 6 | Racking Board and Fingerboard | Separates and stabilizes stands of drill pipe, casing, or other tubulars above the rotary table. | Fixed or adjustable fingers; spacing selected to match tubular outside diameter and stand arrangement. | Structural steel frame with replaceable wear pads or pipe-contact components. | Tubular compatibility, impact resistance, load distribution, corrosion protection, and safe manual handling. | API Spec 4F; site lifting and tubular-handling procedures. |
| 7 | Guy Lines and Mast Bracing | Control lateral movement and improve stability under wind, operational, and erection loads. | Wire-rope or rigid-brace systems arranged according to the mast design and foundation layout. | Galvanized or ungalvanized high-strength wire rope, turnbuckles, shackles, and structural braces. | Pretension, anchor capacity, fatigue, corrosion, termination efficiency, and regular visual inspection. | API Spec 4F; API RP 9B; ASME B30.26 for rigging hardware where applicable. |
| 8 | Mast Raising and Lowering System | Raises, lowers, or erects the mast during rig mobilization and dismantling. | Hydraulic cylinders, drawworks-assisted systems, or hinged erection mechanisms with locking devices. | High-strength steel cylinders, pins, clevises, hydraulic lines, and mechanical locking components. | Controlled movement, hydraulic pressure capacity, emergency retention, pin security, and operator visibility. | API Spec 4F; API RP 54; applicable hydraulic and lifting-equipment requirements. |
| 9 | Base Hinge, Pins, and Mast Footings | Transfer mast reactions to the substructure and permit controlled pivoting during erection. | Heavy-duty pinned joints with replaceable bushings, thrust surfaces, and engineered foundation interfaces. | Forged alloy-steel pins, machined bushings, and reinforced structural-steel base plates. | Shear and bearing stress, pin retention, alignment, lubrication, foundation settlement, and inspection access. | API Spec 4F; structural design codes applicable to the installation location. |
| 10 | Access Platforms, Ladders, and Fall-Protection Systems | Enable inspection, maintenance, and safe movement around the derrick or mast. | Grated walkways, fixed ladders, handrails, toe boards, vertical lifelines, and designated anchor points. | Hot-dip galvanized or coated structural steel; stainless or corrosion-resistant hardware where required. | Working load, slip resistance, ladder angle, guardrail height, dropped-object control, and corrosion environment. | API Spec 4F; ISO 14122; OSHA or equivalent local fall-protection regulations. |