Improving fatigue resistance of steel catenary risers

A method of installing a steel catenary riser 14 comprises progressively unspooling and launching the riser from a reel-lay vessel 10. The riser is plastically deformed in a straightening process aboard the vessel downstream of unspooling and upstream of launching the riser. The straightening process is adjusted to form a series of two or more residual curvature loops 28 of locally increased curvature in a length of the riser suspended in the water column above a touch-down point. Successive curved regions of the series are separated and joined by a straighter portion 30 of the riser of lesser curvature than those loops. Buoyancy elements (Fig 5, 45) may be attached to at least one straighter portion of the riser above at least one of the loops of the series, or between successive loops of the series, or above the series of loops.