Casio makes military grade timepieces. This is a bold statement that is not hyperbole nor am I paid to say this. One of their brand lines the, 'G-Shock,' is a favorite of military professionals throughout the world especially Navy SEALS who work in and around the ocean. Many use the G-Shock-G-Rescue.
I recently gave a G-Shock, G-Rescue; (under $100), to my best friend. We have been surfing together since we were 17-years-old and I picked the G-Rescue primarily for both the graphical tide & moon phase views built into the interface. Note the G-Rescue has a stopwatch function that produces split times as well.
After sending him the latitude & longitude coordinates for his favorite surf break; (easily found online HERE via Google), providing the mean tide interval averages; (Found on the same NOAA page), this is what he had to say:
"... I just finished programming my watch, it was actually pretty easy! I just checked the tide indicator against a tide book and its dead on! I also checked the moon phase and it is dead on as well! I'm stoked. It will also show you tides and moon phases for any date through 2099.
Thanks ... its an awesome watch.
[...]Sadly, to further prove my statement that Casio creates military grade time-pieces, they have a secondary model they sell for just $8.00 which is also nicknamed the "terrorist watch." Here is a Wikipedia article about it if you are interested: [Link]