Vessel Squat & Propeller Wash Calculator – Port Design & Erosion Risk

Vessel Squat & Propeller Wash Calculator

Squat estimation (Ankudinov/ICORELS) · Propeller jet velocity (Hamill/PIANC) · 2D profile · Erosion risk

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📐 1. Vessel Squat & Propeller Wash – Why It Matters

When a vessel moves through a confined channel, it sinks deeper due to hydrodynamic effects – this is squat. Excessive squat can lead to grounding. Additionally, the propeller generates a high‑velocity jet that can erode the seabed and damage quay walls. This calculator uses widely accepted methods from PIANC, USACE, DNV-GL.

Ankudinov squat: δ = C_b × V² / (100 × (h – T))
ICORELS squat (inland vessels): δ = K × V² / g
Propeller jet velocity (Hamill): V_jet = V_ship × (P/A)^0.5 ... simplified empirical formula.

🚀 2. Live Squat & Jet Calculator

Vessel Speed (V) knots

Block coefficient (C_b)

Water depth (h) m

Vessel draft (T) m

Propeller power (P) kW

Propeller diameter (D_p) m

Method

Batch CSV Upload

✅ CSV: speed, Cb, depth, draft, power, propDia

Get PDF Report via Email

CSV Template

📊 2D Squat Profile & Propeller Jet Plume

📊 Squat Comparison & Erosion Risk

📈 Squat Trend & History

📂 3. How to Use the Calculator

Enter vessel parameters: speed (knots), block coefficient, draft, water depth.
Enter propeller data: power (kW) and diameter (m).
Select squat method: Ankudinov for open water, ICORELS for confined channels.
Compute: Click "Compute" – squat and jet velocity appear, along with erosion risk.
2D visualisation: Shows vessel profile, water level, squat, and propeller jet plume.
Batch CSV: Upload multiple designs for bulk analysis.
PDF Report: Download a report with the canvas image.
History: All calculations saved locally; export or clear anytime.

📈 4. Real‑World Example

Container vessel in Chittagong port channel
Speed = 10 kn, Cb = 0.7, depth = 12 m, draft = 5 m, power = 3000 kW, prop dia = 3.5 m.
Squat (Ankudinov) ≈ 0.29 m, jet velocity ≈ 5.5 m/s → moderate erosion risk. Reduce speed to 8 kn to lower squat.

❓ Frequently Asked Questions

❓ What is the acceptable squat limit?

General rule: squat should not exceed 10% of draft. For critical channels, use dynamic under‑keel clearance (UKC) analysis – see our UKC calculator.

❓ How to reduce propeller erosion?

Reduce vessel speed, use larger propeller diameter, or install erosion protection mats – see our riprap sizing tool.

❓ Which method should I use?

Ankudinov is preferred for open sea; ICORELS for rivers and confined channels. PIANC guidelines provide further details.

🌐 Industry Standards & References

PIANC – International Navigation Association | USACE – Navigation Manuals | DNV-GL – Ship Design Guidelines | ICORELS – Inland Waterways

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