Topic 1. # of LEGs for a TLP ( 3 or 4 )

Aspect 1. Initial Tension

Comparing the initial tension (f) against overturning moment (Mmin) for 3-legged and 4-legged TLPs (Tension Leg Platform).

The initial tension for a 4-legged TLP can be reduced to 53% of that of 3-legged TLP. — comparison of initial tension

( Sample calc. )

● # of required wires corresponding to the maximum overturning moment

For a 3-legged TLP, when each leg consists of 4 wires, 12 wires are required in total.

For a 4-legged TLP, the max. tension can be reduced to 53%, each leg requires 2.12 (= 4 * 0.53) wires. With increasing the design strength per wire by 6%, the 4-legged TLP can be supported with only 8 wires.

Aspect 2. Tendon Length Adjustment for Seabed Uplift and/or Subsidence

(UNDER CONSTRUCTION)

A 4-legged Grip-TLP can balance tendon tension by shifting ballast between grips.