The chain length dependence of the intrinsic viscosity and the Stokes radius demonstrates that denatured proteins are not in the "unperturbed" state but rather have nonlocal excluded-volume interactions between residues. Here, we present hydrodynamic calculations on denatured protein chains with N = 16 to 104 residues. Chain conformations were generated by sampling (phi,psi') from those collected from loop regions in the protein structure database. Excluded-volume effects were explicitly accounted for by assigning a hard-sphere diameter d(alpha) to the C-alpha atoms. The value of d(alpha) for a chain at a given length was adjusted so the experimental intrinsic viscosity is reproduced. This procedure allowed a simultaneous reproduction of the experimental Stokes radii for all the chain lengths studied. The distribution of the end-to-end distance R and its mean square [R-2] were obtained from the sampled chain conformations. When the chain length dependence of the intrinsic viscosity and the Stokes radius is fitted to the Zimm model (which predicts [eta]M = Phi(R-2)(3/2) and R-s = K[R-2](1/2)), the length dependence of the coefficients Phi and K is obtained. The effective bond length b(eff) [defined via [R-2] = (N - 1)b(eft)(2)] ranges from 5.71 to 8.78 Angstrom, and the distribution of R is nearly Gaussian when N > 30. The value of b(eff) is extrapolated to increase to 10.6 Angstrom at N = 1000. For any chain, the distance between two interior residues is characterized by a shorter effective bond length than the end-to-end distance.