Optimoor 

              

Manufacturer: Tension Technology International

Website: http://www.tensiontech.com/software/optimoor.html

 

Data Input:

  • Dimensions of vessel and mooring lines in Vessel Lines Screen

  • Dimensions of berth and ship mooring points in Berth Screen.

  • Mooring arrangement in Mooring Screen with extra features drag-and-drop in graphical interface.

  • Wind, current and tides in General Environment Screen.

  • Special circumstances such as a tug boat, ice bergs, a passing vessel and wind gusts.

  • Catenary effects

  • Different types of wire: steel, kevlar, nylon, polyester, polypropylene, chain, dynamax, VETS.

     

Applications:

 

Any type of vessel that is moored alongside a pier, a sea island or at any offshore ship mooring.
There is a normal and a dynamic version available. Special feature of the dynamic verison are vessel movement after sudden mooring-line failure, wind gusts, sudden change in current after turn in tide, a passing vessel, static thruster requirements for a DP Ship.

In addition the dynamic version can be used for all types of single moorings and turrets because of their freedom of movement and relatively long natural periods. Free drifting can also be modelled, taking into account wind, waves, current and tug boats.

 

Users:

 

U.S. Clients and Projects

  • Allied Signal
  • Conoco, Inc
  • Du Pont
  • Exxon Oil Corporation
  • Mobil Corporation
  • Shell Oil Company (Riser Protection Net)
  • U.S. Navy

International Clients and Projects

  • AMEC Offshore
  • Aramco
  • British Petroleum Company
British Telecommunications

 

Documentation:
  • Ongoing research and development for future program releases

  • Clear and easy to reference manuals.

  • Hotline telephone, fax and e-mail support by experienced engineers.

Computer systems:
  • PC (IBM compatible).

  • Runs in Windows 95, 98 and NT. Does not run under Windows 3.1

  • MS-DOS version available, which runs under Windows 3.1
Postprocessor output:
  • Mooring line and fender loads, vessel movements and change in freeboard.

  • Local current and tidal current forces and moments, wind forces and moments in Environment Screen.

  • Heaviest wind load from least favourable direction, plotted in “Wind Force Rose”

  • Change in mooring loads over time.

  • Line tending feature to show how to alleviate the burden on overloaded mooring-lines
Solution:

 

Normal analysis is quasi-static. Disequilibrium-force, which is defined as the difference between external forces and mooring-line reaction forces, is calculated for assumed position. Position is changed by iteration until satisfactory equilibrium is reached.

When equilibrium is not reached within 1000 iterations, the message “Inadequate Mooring” appears, which can be due to physical problems.

In the dynamic analysis short-term behaviour is dominated by forces that change over a time-scale of seconds and minutes. Forces that change slower than than the natural periods of mooring-oscillations have little dynamic effect and can be calculated accurately enough and much easier through the quasi-static method.

The dynamic disequilibrium-force is calculated in the same way as for the quasi-static situation. However, instead of convergence to an equilibrium, accelerations are calculated. Velocity and position of the vessel are calculated through integration over time over time intervals of 0.1 second. All forces are assumed to be constant in this interval. At each new time-interval, all forces are recalculated.

Results are presented graphically and can be edited in the “plot-window”.

 

Modelling:
  • Quasi-static and dynamic analysis of mooring lines and fender loads, vessel movements and change in freeboard.

  • Special circumstances such as DP-thrusters, winches, ice, tug boats, wind gusts, change in mooring loads over time and low frequency motions.

  • No different soil types, no animations possible and no hydrodynamic interaction between floating bodies

 

Loading:
  • Tide (OCIMF-based)

  • Local current (OCIMF-based)

  • Wind (OCIMF-based)

  • Catenary effects

  • Thruster loads, constant or time-dependent directional

  • Ice, tug boats, wind gusts, line failure
Summary:

OPTIMOOR is a mooring-analysis program based on OCIMF recommendations and procedures. There is a version for vessels alongside a pier near the shore and in addition one for offshore areas. It is possible to simulate quasi-static as well as dynamic situations. The program is meant to plan and analyse a vessel’s mooring arrangement and to train the crew how to handle the moorings and how to react to in different situations.

Wind Force Rose