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Displacement 110,884 mt
Hull Particulars: (800,000 bbl Storage Tentech Barge)
Loa 200.60 m
Breadth 42.00 m
Draught 19.50m
4.2.4 Turret Design and Selection
There is a wide range of FPSO turret designs available on
the market to suit new build and/or tanker conversion with
basically four main experienced designers providing the FPSO
turret and the buoy systems worldwide:
1. SBM/Imodco (www.singlebuoy.com)
2. Bluewater (www.bluewater-offshore.com)
3. Sofec (www.fmcsofec.com)
4. APL (www.apl.com)
These main contractors offer a range of services from a
straightforward turret delivery to a more comprehensive role with
total FPSO delivery and operation. There are several other
companies offering related turret designs on a niche basis.
Designs
When designing turret mooring systems for ship-shaped
vessels, one of the most important vessel design factors affecting
the mooring line tensions is the location of the turret. The farther
forward the turret is located away from the mid-ship, the easier it
becomes for the vessel to weathervane into an equilibrium heading
under non-collinear environments.
However, the farther away the turret is placed, the more the
vertical motions at the fairleads due to the vessel pitch will
increase, which could have an adverse effect on the mooring line
tensions in the line dynamic mooring analysis.
If the turret position is moved from a bow position to a
position one-third the vessel length back from the bow, the intact
minimum mooring line tension safety factor can improve by 15 to
18%.
In addition to considering the optimum position of the
turret with respect to mooring line tension, it is equally important
to evaluate the impact of the turret incursion into the vessel hull,
and cost the impact. The following items can have a major design
and cost impact on the vessel development:
 Loss of cargo tank volume

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