We use a complex modeling with finite elements that allow the consideration of temperature variations, interior pressures and interactions with the body of the ship. For the cargo transfer installations of oil tankers we study the behavior of eight pipe system models, which have different dilatation lyre (U compensator) arms. This gives the pipe system an extra elasticity and is usually preferred for compensating thermal dilatations and displacements required by the deformation of ship's body. Based on these analyses we can obtain practical recommendations useful in designing.