For sailors, knowing the depth of the water beneath your boat is crucial - particularly if you do not want to run aground.
But large parts of the seas around the UK have not had their depth measured for well over a century, back when the method of choice was to throw over some lead and make note of when it hit the bottom.
One innovative project, Teamsurv, wants to harness the hundreds, maybe thousands, of boats out on the water to start collecting up-to-date information about what lies beneath the surface.
By providing a small data logger to put onboard, Teamsurv can collect and collate the voyages of boats and build up a more detailed map.
The data is published online and made available to other organisations to use, share and adapt.
Teamsurv has been granted funding for its project from the UK Satellite Navigation Competition, an initiative set up to support start-ups that use satellite data.