Load chart practice
Work through 10 original problems on two invented hydraulic telescopic-boom style charts. Practice selecting a cell, subtracting deductions and checking a payload against net capacity.
Method checked against OSHA 29 CFR 1926.1417 on 17 Oct 2026. A calculation aid for study and estimating, not a substitute for the listed equipment's documentation or the AHJ.
Practice a 10-problem set
The same seed recreates the same questions (generator v1). Each set uses both charts. Answers and progress stay in this page until you reload or start a set.
Active seed: 20261017 · Answered 0 of 10 · Correct 0
Problem 1 of 10 · Practice A
All conditions in Practice A apply. Loaded radius: 40 ft. Main-boom length: 100 ft.
What is the gross chart capacity (lb)? Do not subtract deductions for this question.
Practice A: hydraulic telescopic main boom
PRACTICE CHART: invented for training. Not any manufacturer's chart and not an exam chart.
Lift area: 360° on fully extended outriggers. Fictional standard counterweight installed; crane level on firm support; stationary main-boom lifts only. No on-tire or pick-and-carry ratings.
| Radius (ft) | 40 ft boom | 60 ft boom | 80 ft boom | 100 ft boom |
|---|---|---|---|---|
| 10 | 36,000S | 32,000S | 28,000S | 24,000S |
| 20 | 36,000S | 32,000S | 28,000S | 24,000S |
| 30 | 24,000T | 24,000T | 24,000T | 24,000S |
| 40 | — | 18,000T | 18,000T | 18,000T |
| 50 | — | 14,400T | 14,400T | 14,400T |
Bold stepped line: S = synthetic structural limit above the line; T = synthetic stability limit below it. Both are limits. This line is not a safe/unsafe divider.
- For these practice charts only: keep an exact row/column; between entries, use the next longer radius and next longer boom. Do not interpolate or extrapolate.
- A dash means no rating. Do not substitute another cell. Practice range: radius 10–50 ft, main boom 40–100 ft; radius must not exceed boom length minus 10 ft.
- Use the stated lift area and setup. Practice B has no over-front or over-side rating. An erected jib is unloaded here; these are not jib-tip ratings.
- Subtract one active hoist attachment, one jib allowance and the specified rigging. No other suspended gear is present in these problems; do not subtract the same item twice.
Invented deductions (lb): hook block 600; headache ball 200; jib removed 0 / stowed 800 / erected 1,800; rigging as given in each problem.
View the other practice chart
Practice B: hydraulic telescopic main boom
PRACTICE CHART: invented for training. Not any manufacturer's chart and not an exam chart.
Lift area: over rear only on fully extended outriggers. Fictional standard counterweight installed; crane level on firm support; stationary main-boom lifts only. No on-tire or pick-and-carry ratings.
| Radius (ft) | 40 ft boom | 60 ft boom | 80 ft boom | 100 ft boom |
|---|---|---|---|---|
| 10 | 30,000S | 26,000S | 22,000S | 18,000S |
| 20 | 27,000T | 26,000S | 22,000S | 18,000S |
| 30 | 18,000T | 18,000T | 18,000T | 18,000S |
| 40 | — | 13,500T | 13,500T | 13,500T |
| 50 | — | 10,800T | 10,800T | 10,800T |
Bold stepped line: S = synthetic structural limit above the line; T = synthetic stability limit below it. Both are limits. This line is not a safe/unsafe divider.
- For these practice charts only: keep an exact row/column; between entries, use the next longer radius and next longer boom. Do not interpolate or extrapolate.
- A dash means no rating. Do not substitute another cell. Practice range: radius 10–50 ft, main boom 40–100 ft; radius must not exceed boom length minus 10 ft.
- Use the stated lift area and setup. Practice B has no over-front or over-side rating. An erected jib is unloaded here; these are not jib-tip ratings.
- Subtract one active hoist attachment, one jib allowance and the specified rigging. No other suspended gear is present in these problems; do not subtract the same item twice.
Invented deductions (lb): hook block 500; headache ball 150; jib removed 0 / stowed 700 / erected 1,600; rigging as given in each problem.
Read the configuration before the numbers
Start with the correct equipment, boom, attachments, support setup and lift area. Follow the chart's own instructions for intermediate dimensions and deductions; our ceiling rule is only a rule for these invented charts. A capacity comparison alone does not check ground support, rigging limits, line pull, weather or the lift path.
OSHA requires applicable manufacturer procedures to be followed, load charts and procedures to be available to the operator, and rated capacity not to be exceeded. Our practice rounding rules, bold line and synthetic numbers are not OSHA ratings or procedures. Always use your crane's own chart and procedures.
Source: Occupational Safety and Health Administration (OSHA), 29 CFR 1926.1417 — Operation, sections (a), (c)(1), (o) and (r). Checked 17 Oct 2026. This public general source supports the manufacturer-procedure guidance; it does not supply our invented chart data.
Formulas and a worked example
Net payload capacity = gross chart capacity − total applicable deductions. Payload is within this arithmetic limit when payload ≤ net capacity. Percent of net capacity = payload ÷ net capacity × 100. This is different from total suspended load ÷ gross capacity; every percentage question here explicitly uses net payload capacity.
Example: Practice A, radius 25 ft and main boom 70 ft. These practice notes select the 30 ft row and 80 ft column: gross capacity 24,000 lb. With a 600 lb hook block, 800 lb stowed jib allowance and 200 lb rigging, deductions total 1,600 lb. Net capacity = 24,000 − 1,600 = 22,400 lb. A 16,800 lb payload is within that limit and uses 16,800 ÷ 22,400 × 100 = 75.0% of net capacity.
Where the practice numbers come from
Source: Boom Angle editorial team, Synthetic practice-chart specification v1, 17 Oct 2026 (original teaching model, not published crane reference data). No manufacturer chart, NCCCO chart or real or recalled exam item is reproduced.
At listed radius R (ft) and main-boom length L (ft): S = B − 200 × (L − 40); T = M ÷ R; gross capacity (lb) = 100 × floor(min(S, T) ÷ 100). Practice A uses B = 36,000 lb and M = 720,000 lb·ft; Practice B uses B = 30,000 lb and M = 540,000 lb·ft. S ≤ T is labelled structural; otherwise stability. The bold line follows that change in each column. Cells with R > L − 10 are blank.
These constants, the geometry cutoff and all deduction allowances are invented. The formula simply creates round, decreasing teaching values; it is not an engineering method for determining a crane's actual capacity. The net-capacity and percentage equations above are arithmetic definitions used by these exercises.