DNV-ST-0378 Padeye Design: A Complete Guide for Offshore Engineers

Padeyes are among the most safety-critical items on any offshore module, container, or piece of equipment. A lifting lug that fails during a crane pick over the side of a vessel doesn't just lose equipment — it risks lives and triggers regulatory investigations. Yet padeye drawings routinely arrive at yards with missing weld symbols, no material certificates, and no NDT callout.

This guide covers padeye design to DNV-ST-0378 Appendix E — the applicable standard when you're designing a lifting point that will be used in a DNV-classed offshore lift. It covers all five utilisation checks, how to select your DAF, pin hole tolerancing, weld requirements, and the eight things every compliant padeye drawing must include.

1. Scope: When does DNV-ST-0378 apply?

DNV-ST-0378 ("Offshore and platform lifting appliances") governs the design, fabrication, and certification of lifting appliances used in offshore operations. It applies when equipment is lifted on or off offshore installations or vessels in DNV-classed operations.

Appendix E covers padeye design specifically — including SWL marking §E.2, dynamic amplification factor §3.4, pin hole tolerances, weld requirements, and material certificate requirements EN 10204 §3.1.

Standard	Covers	Applies to
DNV-ST-0378 App. E	Padeye/lifting lug design on equipment	Equipment being lifted
NORSOK R-002	Lifting equipment system (cranes, slings, rigging)	The crane and sling system making the lift
EN 13852-1	Offshore cranes — general purpose	Crane itself

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In practice: Both DNV-ST-0378 and NORSOK R-002 apply simultaneously on an NCS lift. The padeye on the topside module uses DNV-ST-0378 App. E for design. The crane and sling system is governed by NORSOK R-002. They refer to each other and must be consistent — especially on DAF selection.

2. Appendix E structure — the five checks

Appendix E of DNV-ST-0378 defines five utilisation checks that must all pass (≤ 1.0) for a padeye to be considered structurally adequate:

#	Check	Clause	Limit
1	Pin hole bearing stress	§E.4.2	≤ 0.9 × f_y
2	Cheek plate weld throat	§E.4.3	Minimum throat per weld class
3	Main plate shear-out area	§E.4.4	Gross shear area check
4	Combined stress at hole edge	§E.4.5	Von Mises ≤ f_y
5	Sling angle factor	§E.3	Applied to all load calcs

All five utilisation ratios must be ≤ 1.0. If any one fails, the padeye must be redesigned — typically by increasing plate thickness, enlarging the cheek plates, or increasing weld size.

3. Design load: SWL × DAF × sling angle factor

The design load applied to a padeye is not simply the Safe Working Load (SWL). It must account for dynamic effects and sling geometry:

F_design = SWL × DAF × K_sling where K_sling = 1/cos(θ), θ = sling angle from vertical

Example: A padeye rated SWL = 10t, DAF = 1.15, two-leg sling at 60° included angle (θ = 30° from vertical):

K_sling = 1/cos(30°) = 1.155 F_design = 10t × 9.81 × 1.15 × 1.155 = 130.2 kN per padeye

The sling angle significantly amplifies the load on each padeye. A four-leg sling at a shallow angle can double the load on each lifting point compared to a vertical lift. Always confirm the sling geometry is defined before finalising padeye sizing.

4. DAF selection guide

The Dynamic Amplification Factor (DAF) accounts for crane acceleration, wave-induced vessel motion, and impact during the lift. The DAF must be stated on the lift plan and traceable to the padeye design.

DAF	Scenario	Reference
1.05	Crane on fixed platform, calm conditions, shore lift	DNV-ST-0378 §3.4
1.10	Moderate offshore lift, stable crane vessel	§3.4
1.15	Standard NCS offshore lift, moderate sea state	NORSOK R-002
1.25	Heavy lift or lift from floating barge	§3.4
1.35	Splash zone lifts, high sea states, no dynamic analysis	§3.4

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Common mistake: Using DAF = 1.05 for an offshore crane lift. This is only appropriate for fixed-platform or onshore lifts. For standard NCS offshore work, 1.15 is the minimum without a dynamic analysis. Using a lower DAF without justification is a CRITICAL design deficiency.

5. The five utilisation checks in detail

Check 1 — Pin hole bearing stress §E.4.2

The pin bears against the hole wall in the main plate (and cheek plates if present). The bearing stress must not exceed 0.9 × the material yield strength f_y:

σ_bearing = F_design / (d_pin × t_total) ≤ 0.9 × f_y t_total = main plate + both cheek plates; d_pin = shackle pin diameter

Check 2 — Cheek plate weld throat §E.4.3

When cheek plates are used, the fillet weld between the cheek plate and main plate must be sized to transfer the cheek plate load. The minimum weld throat a_min depends on the weld classification per DNV-ST-0378 Table E-1. Full penetration is required when cheek plate thickness exceeds the limit in §E.4.3.

The weld symbol must appear on the drawing per ISO 2553 — both the throat size and weld process. A missing weld symbol on a cheek plate is one of the most common CRITICAL drawing findings.

Check 3 — Main plate shear-out §E.4.4

The gross shear area through the plate on both sides of the pin hole must resist the design load without yielding:

A_shear = 2 × (R_outer − r_hole) × t_main τ_max = F_design / A_shear ≤ f_y / √3

Check 4 — Combined stress at hole edge §E.4.5

The hole edge stress state is biaxial — hoop stress from the pin bearing, plus bending if the load is not perfectly in-plane. DNV-ST-0378 requires a von Mises check at the critical point on the hole periphery:

σ_vM = √(σ_x² − σ_xσ_y + σ_y² + 3τ_xy²) ≤ f_y

This check often governs for padeyes with small outer radius-to-hole-radius ratios. The Leide padeye calculator runs all five checks automatically with clause citations.

Check 5 — Sling angle factor §E.3

As described in Section 3 above, the sling angle amplifies the design load. The factor K_sling = 1/cos(θ) must be applied to the SWL×DAF product before any of the four structural checks above. A common error is applying the sling factor only to some checks — it must propagate through all of them.

6. Pin hole tolerancing (ISO 2768)

DNV-ST-0378 requires the pin clearance to be controlled. The shackle bore clearance must be ≤ 6% of the shackle pin diameter (i.e., the pin must fill at least 94% of the bore). Alternatively, the drawing must specify the hole tolerance explicitly.

Approach	Note
ISO 2768-m (medium)	Default general tolerance — acceptable for most padeyes
ISO 2768-f (fine)	Use when tight pin fit is critical (e.g. large pin diameters)
Explicit tolerance callout	Always preferred for the pin hole — e.g. ⌀60 ^+0.5₀

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Best practice: Call out the pin hole diameter and tolerance explicitly on the drawing, even if ISO 2768-m applies generally. A note like "Pin hole ⌀60 H11 per ISO 2768" is unambiguous and eliminates common fabrication queries. Relying on a general tolerance note for the most critical dimension on a lifting lug is a MAJOR finding risk.

7. Weld requirements and NDT

The padeye-to-parent-structure weld is the most safety-critical weld on the assembly. DNV-ST-0378 requires:

Full penetration weld between padeye main plate and parent structure — verify the weld symbol shows full penetration (butt weld symbol or explicit note "CJP" / "full pen")
Weld size and process specified — ISO 2553 or AWS A2.4 symbols with throat/leg size
NDT requirement noted — UT or MT on all padeye-to-structure welds per DNV-ST-0378. This must appear on the drawing, not just in the project specification
PWHT requirement — required when wall thickness and material grade trigger it (check DNV-ST-0378 Table for thresholds)

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Missing NDT callout is a CRITICAL finding. DNV-ST-0378 mandates NDT on load-bearing padeye welds. If the drawing doesn't specify UT or MT, the fabricator has no obligation to perform it — and the weld may not be inspected before a lift. This is non-negotiable for any DNV-classed operation.

8. Material selection and EN 10204 §3.1

DNV-ST-0378 App. E §E.2 requires EN 10204 Type 3.1 (or 3.2) material certificates for padeye plates and cheek plates. A Type 2.2 test report is not sufficient.

Certificate Type	Content	Accepted for padeyes?
EN 10204 Type 2.1	Declaration of conformance only	❌ No
EN 10204 Type 2.2	Test report — non-specific tests	❌ No
EN 10204 Type 3.1	Specific inspection cert, manufacturer authorised inspector	✅ Yes (minimum)
EN 10204 Type 3.2	Specific cert, independent third-party inspector	✅ Yes

Grade selection: S355 is the standard structural grade for offshore padeyes. S450 is used where weight is critical. For through-thickness loading (where the design load is applied perpendicular to the plate face — Z-direction), specify through-thickness properties: S355NL-Z35 or equivalent. Missing Z-direction specification on a plate under through-thickness load is a CRITICAL finding.

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On the drawing: The material spec must explicitly reference EN 10204 §3.1. A note stating "Material: S355" without the certificate type reference does not satisfy DNV-ST-0378 and will fail a drawing compliance review. Write: "S355NL to EN 10025-3, EN 10204 Type 3.1 certificate required."

9. Drawing compliance checklist

A compliant padeye drawing per DNV-ST-0378 App. E must include all of the following. Missing any of items 1–6 typically results in CRITICAL or MAJOR findings:

SWL — clearly stated in tonnes or kN, positioned prominently on the drawing
Pin hole diameter with tolerance — explicit callout, not relying on general tolerance only
Material specification — grade, standard reference, and EN 10204 §3.1 certificate requirement
Weld throat and symbol — complete weld symbol per ISO 2553 or AWS A2.4, including throat size and process
Full penetration note — explicit CJP or full penetration callout on padeye-to-structure weld
NDT requirements — UT or MT, scope and acceptance criteria reference (e.g. ASME V + DNV-ST-0378)
Cheek plate dimensions — if applicable: thickness, material, weld detail
Surface treatment — corrosion protection class per NORSOK M-501 or project spec
Title block — drawing number, revision, scale, approval signature

10. Common CRITICAL findings in padeye drawing reviews

Finding	Severity	Clause
Missing EN 10204 §3.1 certificate reference on material note	CRITICAL	§E.2
No NDT requirement specified on drawing	CRITICAL	§E.4.1
No weld symbol on cheek plate-to-main plate connection	CRITICAL	§E.4.3
Through-thickness loading without Z-direction property specified	CRITICAL	§E.2
SWL not stated on drawing	CRITICAL	§E.2
Pin hole with no tolerance callout	MAJOR	§E.4.2
DAF = 1.05 used for offshore crane lift without justification	MAJOR	§3.4
Full penetration not specified on padeye-to-structure weld	MAJOR	§E.4.1

Run all five checks automatically

The Leide padeye calculator runs all five DNV-ST-0378 Appendix E utilisation checks — enter your geometry and loads, get clause-cited results instantly. The AI Drawing Checker flags missing weld symbols, incorrect material certs, and NDT omissions on your actual drawings.

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