During the past five years data on tidal currents have been collected in Start Bay by several cooperating teams using a variety of methods. This paper reduces the data to a standard format, and then uses algebraic interpolation to construct contour maps. These show the variation of the peak current speeds and of the residual tidal currents over the Bay. The maps show that the residual currents are negligible along the spine of the Skerries Bank and it is proposed that this is an important factor in understanding the permanence of the Bank.