Every year, fluid flow problems of ever greater complexity are solved by using the techniques of computational fluid dynamics (CFD). Phenomena such as turbulence, chemical reactions, multiphase flows, and radiation are now regarded as routine features of the CFD practitioner's art. For these calculations the most extensively used solution procedures are probably SIMPLE and its derivatives SIMPLER, SIMPLEC, SIMPLEST, and PISO. A detailed analysis of the performance of the SIMPLE solution procedure reveals why it is difficult to capitalize on the potential of vector processors. Two adaptations of the SIMPLE solution procedure are described that attempt to overcome these difficulties. These algorithms are suitable for a number of low-cost workstations with a single attached vector processor and have been implemented on a MASSCOMP 5400. Results presented for two typical test problems illustrate how the final procedure algorithm produces speed-ups approaching those obtained for linear problems.