Iain_S

On the Thames, it is possible to avoid travelling against the tide: on the Ribble Link, you have to punch the tide in the early stages of the passage, either down the Douglas or down the Ribble, depending on your direction of travel.

If there is no non-return valve, the back flush when the pump is switched off can be quite handy for clearing crud from the pump intake..

Prior to the closure of the Forth and Clyde, practically its only use was by fishing boats. Many Forth based boats would go to the West Coast, mainly for herring, which are migratory. During the re-opening cruise, one of the crew of White Wing (33' lugsailed "Baldie") remarked that it was the first time he had been in the pub during the passage, which used to take them about 36 hours. He also said that it was best to be about the 10th boat through, as the ones before would have carved a channel through the silt.

If it's anything similar to our Jabsco one, reversing the motor connections can be quite effective. The Jabsco pump is a centrifugal one, so no danger of a fountain!