CIGRE TB 623/853 COMPLIANT • SWBP & MBR VERIFICATION • CATERPILLAR & TURNTABLE RPM

Subsea Cable Minimum Bend Radius & Spooling Tension Calculator

Compute static and dynamic Minimum Bend Radius (MBR), Sidewall Bearing Pressure (SWBP ≤ 5.0 kN/m), capstan drag force, and variable-diameter carousel RPM during cable lay and transload spooling.

Cable & Spooling Parameters

CIGRE TB 623
mm (e.g. 525kV HVDC)
kN (Caterpillar)

Sidewall Bearing Pressure (SWBP) Verification

WITHIN SPEC ≤ 5.0 kN/m
Calculated SWBP (T / R)
4.11 kN/m
Max Allowable Limit
5.00 kN/m
Safety Margin
+17.8%

Compliant with CIGRE TB 623. Lead sheath, semiconductive screen, and metallic armor are shielded from compressive crushing.

Static Storage MBR (15 × Do)
2.13 m
Minimum static radius on carousel core or storage drum.
Req Carousel Core: ≥ 4.26 m
Dynamic Tension MBR (25 × Do)
3.55 m
Under spooling/pulling tension over deck chutes & sheaves.
Actual Chute Radius: 4.50 m (PASS)

Payload Mass & Spooling Telemetry

Total Cable Mass
3,288 t
Spooling Duration
66.7 hrs
Core Layer RPM
0.51 RPM
Outer Layer RPM
0.15 RPM
Turntable Drive Modulation: Variable frequency hydraulic or VFD sync Ratio 3.47 : 1

Mobilizing Subsea Cable Turntables or CLV Spooling?

Exspeedite TMS models continuous tension logs, quayside SPMT bridge stress, and CIGRE compliance checklists.

Export Engineering Report
01

CIGRE TB 623 / 853 Standards

Submarine power cables require strict adherence to international CIGRE recommendations. Dynamic bending under tension can cause buckling of metallic radial water barriers (lead or corrugated aluminium sheaths) if the MBR threshold or SWBP limit is exceeded during loading or transpooling.

02

Sidewall Bearing Pressure (SWBP)

Calculated as line pulling tension divided by chute or quadrant radius: SWBP = T / R. The industry standard ceiling is 5.0 kN/m for extruded XLPE subsea high voltage cables. Excessive SWBP crushes internal optical fiber elements and causes permanent dielectric distortion.

03

Synchronized RPM Modulation

As cable coils layer outward from the inner core hub (e.g. 7.5m dia) to the outer carousel wall (e.g. 26.0m dia), carousel RPM must automatically decelerate by a factor of 3× to 4× to maintain constant linear linear speed (m/min) and avoid slack bights or sudden tension spikes.

ENTERPRISE SUBSEA FREIGHT & RIGGING AUDIT

Get Official CIGRE Spooling & Heavy Haul Audit

Receive a certified engineering calculation report including SPMT wheel line axle load distributions and quayside load-out protocols.