The sealevel package provides utility functions to read data from sea level data archives such as PSMSL, CSIRO, Colorado.edu and Soest. See http://publicwiki.deltares.nl/label/sealevel for examples.
This package provides functions that can be used to reprocude the analysis in The Effect of the 18.6-Year Lunar Nodal Cycle on Regional Sea-Level Rise Estimates by Fedor Baart, Pieter H.A.J.M. van Gelder, John de Ronde, Mark van Koningsveld and Bert Wouters. See also the discussion of Trends in Sea-Level Trend Analysis.
The project summary page you can find here.