2c_Bow_Ideal

Diagram 1 illustrates an ideal shape for an object which needs to move through water easily. It opens a way with little turbulance, the water flows past the sides without break away and exits, again with little turbulance.

Diagram 2 is of a craft with a rounded bow. If it is not particularly fast moving it will cut through the water with minimal turbulance. If it meets a wave the upper section will broach the wave. It is this profile sometimes used for Shuttle Tankers

Diagram 3 is shaped as 2 but instead of 180 degrees is 360 degrees, circular illustrates an ideal shape for an object which needs water from whatever direction to flow easily around it. It opens a way with little turbulance, the water flows around with minimal break away and exits, again with little turbulance.

Section 2a outlines the dominent choice of Hull, the Standard Tanker, Refurbished or new build. Section 2b covers the limitations imposed by the swivel or other device to accomodate the flow lines whilst at the same time rotating about the mooring. Section 2c deals with a facit of these which is the Bow and ships shape. The most common Bow profile has a Bulbouse Nose, (primarily used to enhance Tankers In Trade cruising ability which is for its main design purpose of delivering cargoes of crude) . An FPSO does very little cruising and many FPSO new builds have other profiles, this Section explains these.

Diagram 4 is shaped as 2 but Has the lower section flattened and sloping in such a way that it mounts up onto the ice and as it rises the weight of the nose of the ship presses down onto the ice with the purpose of breaking the edge of the ice away. When surrounded by ice the rounded sections provide most resistance to buckling

Diagram 6 Explains how the standard bow is designed to function for the standard tanker. This is likely to remain so, since the building of standard hulls is speculated against the standard need, eg cruising in cargo to Asia or Europe from Africa and returning in ballast for a repeat cargo. New Builds for FPSO's without the bulbouse bow are few and far between and very often to other designs, circular, barge shape etc.

Diagram 5 illustrates a reasonably new bow profile from Rolls Ulstein, XBow. Its purpose is to provide a stable ship which passes through a wave. As the wave rises the profile accomodates this by encouraging it to rise up the bow rather than attempting to lift the bow . X Sterns are being developed and this shows the progression of design for a purpose, mainly at this time for support vessels like AHT,s

Profile 1 Ideal Flow

Profile 2 Rounded Bow

Profile 3 All Rounded

Profile 4 Flattened Bow

Profile 5 X Bow

Profile 6 Protrusion