Design & Analysis

Jack-up Irish Sea Pioneer afloat
Irish Sea Pioneer near Liverpool
Jack-up Irish Sea Pioneer at Night
ISP at night

Design & analysis services together with engineering software have formed the back-bone of our business.  The Irish Sea Pioneer was designed by STA in the 90’s and continues to operate in the Celtic Sea. It is a self-propelled jack-up with design optimized for working with unmanned gas production platforms.  STA has specialized in liftboat and jack-up analysis

Finite element model of jack-up Irish Sea Pioneer
Finite Element model linked with AutoCad model

The hull was built by Bollinger Shipyards in LA and the legs and jacking units were built by LeTourneau in TX.
A modified design with 750t crane is the “Irish Sea Pioneer Mk2” shown below.

Jack-up design with 750-ton crane
ISP Modified to SEWOPS with 750 ton Sheerlegs Crane
Open Ocean Stabilized Live Fire Platform
OOSFLP, Open Ocean Stabilized Live Fire Platform for US Air Force

OOSLFP – Open Ocean Stabilized Live Fire Platform for Missile Testing, for US Air Force.  This is a 5-acre floating concrete structure designed for permanent operations, moored in the Gulf of Mexico, off Florida. STA provided the basic design concept and concrete hull global analysis and optimization for hydrodynamic response to Cat-5 hurricane conditions.  A 24-leg semi-taught polyester mooring system was designed.  Mooring analysis was performed in the time domain using both AQWA and OrcaFlex.  PCCI performed model tests at Escondido.

Mat-supported jack-up, MOPU, Maleo Producer
Maleo Producer, MOPU, Indonesia

MOPU – MALEO PRODUCER – Indonesia.  The Maleo Producer is a converted mat-supported jack-up for gas production.  It is located in a seismically sensitive area and required extensive design and analysis efforts in order to obtain ABS certification.  A significant geotechnical site investigation effort was undertaken, partly from the platform, after jacking up on location.

Mat-supported Jack-up Site Investigation
Detailed site investigation inside and around mat, using Roson equipment from Fugro in 2007
Classic Prandtl slip surfaces and heave of soil inside and around mat-supported jack-up
Classic Prandtl slip surfaces and heave of  soil inside and around mat

A Roson was deployed from the installed platform and modified support framing and rigging was arranged to enable sampling right up to the edge of the mat and inside the mat cut out areas.

Classical geotechnical analysis was supplemented by full scale measurement of ground disturbance.

Non-Linear Time Domain Seismic Analysis of Maleo Foundation (courtesy of Jack Templeton, Sage USA)

A Special Session at the Offshore Technology Conference was dedicated to the Maleo Project in 2008.  Some of the papers were authored and co-authored by Bil Stewart.  This OTC session would not have been possible without the author’s help from many talented and exceptional engineers including, Paul Jacob and Ahmed Nisar from MMI Engineering, Jack Templeton from Sage USA, Alan Young, Don Murff and Dan Spikula from GEMS,Inc, Jean Audibert from Quest Geo-Technics, Steve Neubecker from AdvancedGeomechanics, Vladimir Rapoport, Consultant. The ABS team included Bob Pyke, Consultant, Paul Thenhause from ABS Group, John Stiff and Robert Sheppard fromABS Group, Houston, and Yatendra Rajapaska, ABS, Houston. Special thanks are given to the Maleo Producer OIMs, especially Mike Ward, and to GPS Indonesian Manager, MarkO’Connor, who both helped enormously with the Fugro personnel and equipment onboard during the local site investigation around the mat. Santos is thanked for permission to publish papers in this special OTC session.

PLEM beneath CALM Buoy at US Navy SPM Terminal, Okinawa, Japan.
PLEM beneath CALM Buoy at US Navy SPM Terminal, Okinawa, Japan.

PLEM Design for NAVFAC, Okinawa.  STA provided detailed design and specifications, fabrication and installation assistance.

Simulation of Submarine Hose Installation Beneath CALM Buoy in Okinawa

STA uses in-house software developed largely by Bil Stewart for many design problems in mooring and pipe laying.  Some programs, like STA PILE3, for suction embedded or driven anchor piles, are made commercially available.

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