The biggest boat in terms of length in the world is the Knock Nevis at 458.45 meters. It is owned by Fred Olsen Production and is currently being used as a Floating Storage and Offloading Unit (FSO). The Knock Nevis is permanently moored at the Qatar al Shaheen Oil Field in the Persian Gulf as a temporary storage unit for oil drilled offshore to be later transferred to moving tankers. It was originally built in 1979 and changed owners several times before ending up in its current location in 2004. In its previous life, the Knock Nevis served as a container ship that was so big, that it couldn’t safely navigate through the English Channel, let alone man made channels like the Suez Canal.

The Qatar al Shaheen Oil Field sits on the largest deposit of natural gas in the world; the North Gas Field, shared jointly between Iran and Qatar. The Qatari side of the oil field is being investigated for structural integrity due to heavy extraction, and aside plans that have already been approved, extraction is being put on hiatus. If too much natural gas is removed at once, the gas field’s future production potential could be limited due to a drop in pressure.

A variation of an FSO is a PFSO; a Production, Floating Storage and Offloading Unit. This vessel has the further capability of processing the raw production fluid from oil wells before depositing the product into storage containers. There are several large PFSO’s in operation, and they, like the Knock Nevis are usually converted from former container ships.