It seems that the technology is already out to accomplish something that would let someone calculate their own exact ET and MPH with out going to the track.
The GPS is already calculating time and distance and reading out MPH.
If the time and distance was read out as well as the MPH you would have what you need.
This unit is already out, Runners wear it as a wristband.
For our use you would have to be able to push a set button that would start the run and at that point the unit would calculate the distance and stop at the preset distance you wanted. Either 1/8 or 1/4 mile and read out your results.
The GPS update speed would be a question but the units already interpolate between update times.
Beyond that if the GPS info was relayed via a cellphone signal the data could be read at a location on shore, in a timing tower, or anywhere. There are cellphones out that have a GPS built in now.
If two boat had the same unit and the remote location started the run when the two boats were lined up the ET and speed would be calculated.
You wouldn't even need a course set up and the boats wouldn't need to be lined up exactly at the start.
Input ?
Any GPS tech experts out there ?
Any software experts?