OCEN 201 Introduction to Ocean & Coastal Engineering Mooring System Jun Zhang Jun-zhang@tamu.edu

Buoy & Mooring System Buoy types and uses Reading assignment (pp 195-198, old edition: pp166-168) Buoys are floating or submerged objects. They can be cylindrical, spherical, disc, cone, or toroid in shape. They are usually moored to anchors at the seafloor through steel chains, cables or synthetic ropes. They are used for measurements, mooring and transport oil and gas

Forced on Buoys Using Morrison Equation for computing the forces Examples (Catenary Anchor Leg Mooring (CALM) ) Moored subsurface buoy (p198, old edition p170) Static Cable Analysis (p198-200, old edition: p171-173) Drag coefficient for 2-D and 3-D body shape (empirical coefficient) (p199 old edition: p172)

Typical Mooring Lines Steel Mooring Lines: Chain-Cable-Chain Polyester Mooring Lines: Steel Chain-Polyester rope-Steel Chain (Taut or Semi taut)

Integration of Mooring Lines Depth 914 m 1,829 m 3,048 m type Steel semi taut Polyester taut pattern 14 point taut-leg omni-directional spread Platform section (K4) 76.2 m x 0.133 m K4 Studless chain 91.44 m x 0.133 m 91.44 m x 0.133m Riser/middle section 975 m x 0.137 m Sheathed Wire 2,377 m x 0.21 m Polyester 4,054 m x 0.23 m Polyester Ground section (K4) 350.5 m x 0.133 m K4 Studless chain 121.9 m x 0.133 m 121.9 m x0.133 m Fairlead 91.44 m ABL Pretension 3,025 kN 2,357 kN 2,891 kN

y y’ x’ S’ x TH Fictitious length --- S’ T0 Mud line

T+dT dsW T

How to apply the formulas Determining the fictitious length, etc.

2. Formulas starting from the touch-down point

Ex. 6.1 at pp202 and pp204 (old edition at pp175)