That Sail hydro is sweet! 46 knots is way fast for a sail boat (Or most regular “Speedboats” for that matter)
52 km/h is less than 50 MPH. Knots are slightly longer than miles, so it’s probably more like 85 km/h and 52mph.
46 knots, equals 52.935852 mph. Conversion factor is 1.1507794 mph, per 1 knot.
Wow. To the 6th decimal place, no less. Whoops, I mean 7th.
That would be seven (7) places.
You’ve got some facility with the old math. I’ll bet you could make a buck with that if you ever put your mind to it, Bill.
Has any consideration been given to the idea that when riding a shorter board, or body board for that matter, one tends to keep the same stance or position, but when riding longer boards, you can walk the length of the board? It would seem to me that a high speed could be recorded at a particular moment if you were walking forward on the board while already traveling at a high rate of speed on the wave. Just a thought.
Hey All,
Just a quick question. Since we’re on the topic of velocity. If velocity is the change of distance over time then what components of a wave would give the surfer the greatest change in distance in the shortest amount of time?
I’m assuming since we’re only talking about max velocity, the only parts of a wave that would make a surfer change distance over time would be the gravitational force (going down) and the wave’s velocity (beachward). So, if we want to maximize these components to attain the most velocity then going down straight down (just like a bottom turn) would be the most efficient way of getting speed as it would maximize G and just go as fast as the wave’s velocity. So a fast giant peaky wave with a surfer going straight down on a board designed with minimum drag would be the ideal conditions to get the most speed. This is all assuming the GPS can record changes in direction in 3D (Up/Down,Forward/backward). Someone please check my physics as I just have a basic grasp of the laws of physics. If what I’m assuming is true then I would suspect that a surfer being pitched “over-the-falls” would get more speed than a surfer on the same wave since the person being pitched is being thrown forward and accelerating faster down the same distance (no board drag).
What a great thread.
-Rio
I think cutting across the beach would make the fastest speed, as you are not only “falling” down the wave face and going forward, you are going down the beach. A wave’s forward velocity is much lower than the speeds that have been reported by TomBloke and others.
Also, velocity is different than speed. Speed is distance travelled/time. Velocity is displacement/time. So if you went 20 miles forward and back in 1 hour, you’d be doing 40 mph, but you’re average velocity in that hour would be zero, as in the time, you’ve moved back to your starting point, so no change in position. Speed is a scalar quantity, with no direction. Velocity is a vector. Speed is just “30mph”. Velocity is “30mph @ 43 degrees north of east”
Nathan,
Right, D displacement/time.
If you’re going across the beach, wouldn’t you be minimizing the downward component? Hmm, this is interesting. I guess I’m assuming that a wave just goes straight onto the beach head on so if you are anywhere on a wave heading straight to the beach, your forward component would just be going as fast as the wave’s velocity. But this is not true as I just realized that waves can wrap around a point and be angled so that you could pump and resonate your board to generate more speed. But is pumping across a wave or going straight down the same wave produce more speed?
I just realized there’s a “Histograph of board speed” thread so this should be exciting to see the data.
Rio
Quote:
46 knots is 52 KPH or 85 MPH !
The Hydroptere is a huge beast.
spuuut
Quote:Roy,you wanna talk speed??
The only sea going vehicle faster than a windsurfer!!! A new benchmark for you? LOL!
Seriously though, I think you will dig their keel design…
Er…I think that should be more like 46 kn ~ 52 mph ~ 85 km/h.
Quote:
Terry, check the top of this page ,
janklow at post 123,
nathanP at post #124
and Bill Thraillkill at post #126
have already picked up my error
and corrected it to the essential seven (7) decimal places.
But thanks for reminding me again.
Let it go guys, it wasnt that bad.
spuuut.
Yeah. They posted their corrections more quickly than I did. I initially added some more info about sea going craft that go faster than hydroptere–but then decided that chasing down the exact numbers was going to take more time than I could spare, so I deleted that part. By then the others had posted, but I wasn’t aware of that.
Quote:
That Sail hydro is sweet! 46 knots is way fast for a sail boat (Or most regular “Speedboats” for that matter)
Consider they are blasting speed records within weeks of launching that baby I think we can expect alot of news from these guys, the Hydroptere is the “little” prototype of what they want to build…
what’s on the agenda?
Transatlantic record?
Cape to Rio?
Round the world?
Tom/Roy , noticed you are now giving reading in kph
the numbers you are posting all of a sudden make perfect sense and are in line with everyone elses numbers
the video you posted oin the histogram thread looks to be going about as fast as i have seen in a video from you so far and you claimed a perfectly believeable speed 20+ mph
http://www.olosurfer.com/17Jul06garmin.wmv
this is a dumb Q but were you always talking in terms of kph
and there was a huge confusion ?
Soul
Quote:
Roy,you wanna talk speed??
The only sea going vehicle faster than a windsurfer!!! A new benchmark for you? LOL!
Seriously though, I think you will dig their keel design…
I presume that you mean wind-powered sea-going vehicle. The offshore power boat record speed is over 200 mph:
“The 3-day event began on Friday with the speed trials, where history was made with the 1st ever-offshore powerboat to exceed 200 miles per hour! Bacardi Silver, (piloted by David Scott and John Tomlinson), had a one-way pass of 202.907 miles per hour, and backed it up with a return pass of 193.198 miles per hour, for a two-way average of 198.052 miles per hour.”
…run speeds in the ocean up to 115 mph:
" If your on the beach or in a boat between Point Pleasant Beach and Bay Head your in for a treat as boats roar down the ocean at speeds up to 115 miles per hour. If the surfs up, the boats will spend more time in the air than in the water."
…and lap speeds (in a sea state in which I doubt a windsurfer could come close to 40 kn) at over 95 mph:
“In Super Vee Unlimited class, The Player, with Chris Witty driving and Simon Fletcher on throttles, a team all the way from England beat rivals Rio Roses Fountain Mercury, who suffered an early breakdown in the 4th lap. At the start of the race Rio Roses Fountain Mercury with Mike Seebold driving and David Knight throttling gave race fans some thrilling moments as had the fastest speeds of the day on their third lap of 95.2mph.”
A number of military ocean-going hydrofoil-based boats have speeds in excess of 46 kn (examples):
“The Canadian Navy built and tested a high-speed anti-submarine hydrofoil, the HMCS Bras d’Or, in the late 1960s, but the program was cancelled due to a shift away from ASW by the Canadian Navy. The Bras d’Or was a surface-piercing type which performed well during her trials, reaching a maximum speed of 63 knots.”
“The Pegasus class ships were powered by two 1,600 horsepower (1,200 kW) Mercedes-Benz diesels when waterborne, giving them a speed of 12 knots. When foilborne, the ships were powered by a General Electric LM2500 gas turbine, good for a speed of 48 knots. Pegasus ships were well armed for their size, carrying two four-rack RGM-84 Harpoon anti-ship missiles and an Oto Melara 76 mm gun. The Harpoons, specifically, were capable of sinking far larger ships at distances in excess of 60 nm. The German version would have carried the MM38 Exocet.”
Some hydrofoil-based passenger ferries can also exceed 46 kn–although I’m not sure that they’re “sea-going” (examples):
“TurboJET’s fleet includes five types of vessels:
- FoilCat : 560 tonnes, 400 passengers catamaran. Propelled by waterjets powered by twin General Electric LM500 gas turbines. Maximum speed at 50 knots. Built by Norwegian specialists Kvaerner Fjellstrand.
- TriCat : 600 tonnes, 300 passengers catamaran. Propelled by waterjets powered by twin Caterpillar Solar Taurus gas turbines. Cruising speed at 45 knots, capable of 50 knots. Built FBM Marine of the United Kingdom.”