HB137 Wakeboat Regulation

[Dave R]

Originally Posted by paintitredinHC

Also worth noting that the the scientific research referenced in the Oregon commission's recommendations state that the maximum wake/wave height associated with WakeBoarding and WakeSurfing drops 27-56% in the first 100-150ft of its travel from the boat path. This ties into previous research shared on this forum by DPatnaude that states that a wake generated by a wakeboat creates a wave from the stern that is more destructive than a boat traveling at headway speed. However, we now can tie the two studies together to see that given 100-150ft, the wave is halved to the level of a vessel traveling at headway speed. Addressing the pedantic among us, there are other environmental factors that can influence these statistics (i.e. wind, current, water depth, etc.) which likely addresses the discrepancy between what those of you 'see' and what is scientifically proven.

I don't really care about wakes, but I like math and boats and feel compelled to point out that if you take a 3 foot wake and halve it,, it's still a 1.5 foot wake, and easily 3 times the biggest wake you would get at headway speed in the vast majority of boats on the lake. As an experiment, go through the Weirs Channel making a 1.5 foot wake and see if anyone complains

[paintitredinHC]

Originally Posted by Dave R

I don't really care about wakes, but I like math and boats and feel compelled to point out that if you take a 3 foot wake and halve it,, it's still a 1.5 foot wake, and easily 3 times the biggest wake you would get at headway speed in the vast majority of boats on the lake. As an experiment, go through the Weirs Channel making a 1.5 foot wake and see if anyone complains

I am a lot of things but an engineer in fluid dynamics is not one of them. Perhaps a more qualified person can elaborate on the details.

That said, I 100% agree that a 1.5 foot wave in the channel would not be ideal. Some of the details of the research I mentioned were not readily available, but I believe the variability in the estimated dissipation rates have to do with several factors. Namely, a WakeSurf wake has significantly more power than a Wakeboard or ski wake. Beyond the fact that the size of the wake is larger for a surf wake (3+ foot variety vs. the 2.5 foot variety for a wakeboarder) -- the power or displacement has to do with how the boat is traveling through the water. For example a wakesurf wake is formed by significantly weighting and/or deflecting water to one side of the boat. Moreover, the sport is performed at a transition speed (~11 mph) which causes significant bow rise and accompanying swell off the stern. This powerful wave dissipates at a slower rate than other waves. As Dan (ishoot308) observed, this causes the boat to behave in a similar fashion the the large displacement hull cabin cruisers.