Page 98 - 4274

 Loss of longitudinal strength
 Introduction of additional stiffening steel to dissipate turret
loads
 Diameter of the turret structure derived architecturally from the
space requirements for the risers, the moorings and the turret
equipment.
 Size of the turret bearing required to efficiently transmit
mooring loads between the turret shaft and the FPSO hull.
When considering the total impact of the turret on the hull,
the bow turret has proven more cost effective in both benign and
harsh environments. The bow turret can be configured in two
ways:
1. Integral bow turret (built within tanker bow) (fig. 4.6)
2. Cantilevered bow turret (fig. 4.7)
A fully weathervaning vessel has opex advantages over a
controlled heading/limited rotation vessel, but the inherent
requirements of a swivel joint for each flow path imposes practical
limitations on the number of flow paths that can be provided for a
fully weathervaning vessel.
Whilst all turret systems are disconnectable, the term is
only used for turrets having the facility for quick connection and
quick disconnection (QCDC). Most of the turret systems that have
been designed for fairly benign weather and shallow water are
disconnected when a typhoon is expected.

98