In this technical report, the work done in the project "communication networks with mobile nodes" during 2008, is described. In present phase of the project the work has mainly been directed towards the link, i.e. the acoustic communication between two underwater modems. A number of signals processing methods have been tested, on one hand, those that have been taken from different articles, and on the other hand those that have been developed by us. There is also a section about a new method for stealth communication, developed by us. Foremost, a new implementation of the equalizer, the phase correction and an improvement of the channel estimation have proven to give good results. In the report, the methods are described and references are given, respectively. We also give results from two practical experiments. One outside of Gotland, done in Sept., and one long time evaluation, which has been conducted for almost the whole year in the Stockholm archipelago. The results from these are so far only partly evaluated. However, improvements as compared to previously, and a good availability of the underwater acoustic link are already shown.