The dynamical characteristics of water absorbed in Nafion are investigated using n.m.r. At temperatures below the dynamical transition temperature, T-t, relaxation rates indicate mobility associated with a fluid but the derived motional activation energies are similar to those of ice. This indicates a well ordered supercooled fluid consisting of hydrogen bonded water structures. The correlation time tau(c) is found to have a Gaussian dependence on the surface area to volume ratio, unlike simple porous systems. We have shown that the surface area depends on r(2.5) We feel that this is due to the irregular nature of the surfaces of the clusters.