  A search for pair produced scalar fermions with couplings that violate
R-parity has been performed using a data sample corresponding to an integrated
luminosity of 56 pb-1 at a centre-of-mass energy of sqrt{s}= 183 GeV collected
with the OPAL detector at LEP. An important consequence of R-parity breaking
interactions is that the lightest supersymmetric particle is expected to be
unstable. Searches for R-parity violating decays of charged sleptons,
sneutrinos and stop quarks have been performed under the assumptions that the
lightest supersymmetric particle decays promptly and that only one of the
R-parity violating couplings is dominant for each of the decay modes
considered. Such processes would yield multi-leptons, jets plus leptons or
multi-jets, with or without missing energy, in the final state. No significant
excess of such events has been observed. Limits on the production
cross-sections of scalar fermions in R-parity violating scenarios are obtained.
Mass exclusion regions are also presented in the framework of the Constrained
Minimal Supersymmetric Standard Model.
