1979 posts
Does anyone know the average speed your doing when powered up on wave sailing gear. I would have thought somewhere between 15 and 20 knots. Not sure if many people have used a GPS with wave gear before.
WA
12885 posts
Somewhere I think I read that waves travel at 15knts in the open ocean. How fast do you think you overtake them???
Think 15knts is too slow even for an average powered up speed. A lot depends on conditions of course, it's always harder to go fast in heavy chop.
NSW
1871 posts
I've done about 25 knots in flat water. At Sandy Point speed strip speeds of up to 37 knots have been recorded on a wave board with speed sail.
1979 posts
I thought that the larger the wave the faster it travelled. I got that from how things start planing . A craft is planing when it is travelling faster than a wave of its own length.
Maybe 15 to 20 is a bit slow, would be good to find out. (Jesus, this is getting a bit technical for a Saturday night)
1116 posts
Only had my GPS out wavesailing once was a 20 to 25 knot day, most of time was around 38km/h [20.5 knots](fastest heading out ans slightly upwind) to about 43km/h [23.2 knots] (fastest coming back in and slightly down wind), top was 46.5km/h [25 kts] (This was achieved deliberatly trying to go as fast as I could at fastest angle downwind).
Hard to go much faster maybe on a 25-30kt, if water surface not too washing machine like, mike hit around 50km [27nots]?? On dead flat water probably around 55.6 km/h [30knots].
NSW
4521 posts
Des,
Did you get out today? The graph looked good for Kyeemagh. I was stuck in my yard hosting a 6 year old birthday party as the gum trees were swaying all around me. Auuugghhh - what an opportunity wasted!!
NSW
1871 posts
Harrow,
Even after breaking a few speed limits I go there too late. It was all over by 3.30. Apparently it was ok (around 6-7m) from about 1 to 3 pm. Monday seems the go.
Des
1979 posts
Thanks, that's the info I was after.
NSW
714 posts
Waves travel at speeds dependent on the water depth. In general the higher the wave the slower it is going. Most of the energy in a wave in deep water is contained in the wavelength. Faster waves have longer wavelengths, but wavelengths are restricted by water depth.
In deep water waves have long wavelengths and small amplitudes. When the wave arrives at the shore, the water is less deep. The reduced depth cannot sustain the wavelength, so physics being as physics is, in order to maintain its energy, it raises in height and reduces in length.
Waves of period 20 seconds travel at about 30kts in deep water. Waves of period 10 seconds travel at about 15kts in deep water.
Tsunami can have lengths measured in 100's of kms, heights of <1m, and travel at speeds measured at over 100kts in deep water.
We all know what this looks like in shallow water, a lot higher, slower and shorter.
Sorry for the lesson,
JB
NSW
3105 posts
From what Ive heard a guy did 39 knots on a JP wave board at Sandy Pt in that big blow not so long ago.
And yes, most of us missed the wind at Botany on Saturday. I checked Longy but it was crap. mate got 2 1/2 hours in. Bugger!!
).
