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maximum draughts, so the typical 2:l ratio can be optimised. This
helps structural design and seakeeping by increasing freeboard
whilst permitting greater bow submergence to reduce slamming.
With regard to the issue of the double hull and the double
bottom hull design, the former has become the norm for FPSOs,
whilst there is little justification at present to impose a double
bottom on a statically moored FPSO. It has become common
practice to arrange ballast tanks outboard of the central cargo
tanks. The ballast capacity depends on the range of operating
draughts due to seakeeping requirements and offloading.
4.2.3 Example FPSO Design
Consider two different design options:
New build Aframax tanker, modified to FPSO
requirements (fig. 4.4).
New build Barge, configured to FPSO requirements (fig.
4.5).

Figure 4.4 – New build Aframax Tanker, 800,000 bbl storage

Figure 4.5 – New build Aker Tentech Barge, 800,000 bbl
storage
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