I use Excel to evaluate the results from different competitions. For exemple
I use an start hour (2005-06-12 09.10.00) and the finish time (2005-06-17
17.39.14) from an offshore sailing race to get the hours sailed. Then I can
convert the hours (128.29.14) to decimal hour by using the =HOUR() etc to
extract the hour, minuts etc. With the decimal hour I can calculate the speed
in km/h or in this case knots.

But my question is how I can go the other way to convert decimal hour (1,5)
to time format (01.30.00)?