Managed only three halfway decent runs, then the police, firefighters and a helicopter tried to save me from the waddensea (being alone on a tideway seems to be a bad idea seen from the dike).

However, I could test my new 2x18.2Hz ublox8 GPS-logger first time on the water. The units sample with an interval of 55ms (0.055s -> 18.2Hz sampling rate)! Here are the first results compared to a GT31(1Hz) and a GW52(5Hz) (could not do 500m due to the shallow waterlevel):

          GT31/1Hz         GW52/5Hz        U8a/18Hz         U8b/18Hz
max   39.266+/-0.194 39.752+/-0.447 40.321+/-0.216 40.350+/-0.227
10s    38.453+/-0.206 38.574+/-0.167 38.447+/-0.031 38.443+/-0.032
250m 38.125+/-0.206 38.206+/-0.144 38.107+/-0.029 38.106+/-0.029

Most striking are the small errors (2 SD) for the 10s and 250m categories due to the large number of samples and Gaussian error cancellation!