What Is the Hudson Formula Breakwater Armor Rock Weight Calculator?
Rubble mound breakwaters protect harbors and coastlines by dissipating ocean wave kinetic energy through rough permeable rock armor layers.
The Hudson formula (USACE Shore Protection Manual / Coastal Engineering Manual) determines the minimum stable individual armor stone mass against dislodgement under design storm waves.
This calculator solves Hudson’s equation for breaking or non-breaking wave conditions, yielding rock weight, median dimension (Dn50), double-layer thickness, and unit density.
How Does the Hudson Formula Breakwater Armor Rock Weight Calculator Work?
The calculation evaluates user-provided measurements using recognized domain equations, converts between measurement units, and adjusts for real-world efficiency factors.
Hudson Formula Breakwater Armor Rock Weight Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
USACE Hudson equation balancing armor stone gravitational submerged weight against hydrodynamic wave drag and lift forces.
How to Use the Hudson Formula Breakwater Armor Rock Weight Calculator
- Enter your primary measurements in the input fields above.
- Select your preferred units (e.g. metric or imperial) if applicable.
- Review or adjust operational assumptions such as field efficiency.
- Click Calculate to instantly generate the full results breakdown and visual chart.
- Use the Reset button at any time to clear the form and test a new scenario.
Step-by-Step Example Calculation
Harbor Trunk Breakwater (H = 2.5 m, 1:2 Slope)
Input Values:
Understanding Your Result
Your calculated result represents the realistic operational capacity or baseline output under the specified conditions. Comparing theoretical and effective outputs reveals the direct impact of turns, overlap, and practical downtime.
Factors That Affect the Result
Field terrain, operator experience, equipment maintenance, overlap margin, and weather conditions can significantly influence real-world output.
When Should You Use This Calculator?
Use this calculator whenever you need quick, verified estimates for job planning, budgeting, equipment sizing, or project timelines.
Assumptions & Limitations
- Hudson Formula: W = (γ_r · H³) / [K_D · (S_r - 1)³ · cot(θ)].
- Nominal rock diameter Dn50 = (W / ρ_r)^(1/3).
- Standard double-layer armor thickness r ≈ 2.0 · Dn50 with packing density based on ~37% layer porosity.
Frequently Asked Questions
Calculation Accuracy & Reference Note
This calculator implements verified, deterministic mathematical equations based on published standards. Results should be treated as professional engineering estimates; always verify critical operations with local equipment manuals and site inspections.