RealSurf Surfers' Forum

ctd wrote: ↑

Mon Aug 13, 2018 3:58 pm

It’s pretty obvious. A joule is equal to the energy transferred to an object when a force of one newton acts on that object in the direction of its motion through a distance of one metre (1 newton metre or N⋅m).

Or in other words kg * m2 / s2; where kg is the kilogram, m is the metre, s is the second

So 1000 of those

(Of course, a wave of 4ft and period of 12 seconds means nothing out of context either. It’s only because you instinctively know what that translates to in the surf relative, to other sizes and periods, that it means anything. I just measure in increments of fear)

No it's not at all obvious. A swell event spreads out across thousands of nautical miles. It strikes here and it strikes there. There's radial spread which varies enormously from swell to swell. A single swell event can span almost the entire Pacific basin. It may also focus on 200 kilometres of coastline.

Again: what does it mean? Where is that 8000 kilojoules of energy likely to be expended? Here? Over there? In what timespan? For how long?

Cranked wrote: ↑

Mon Aug 13, 2018 4:02 pm

200kJ - barely breaking, get out your log
500kJ - surfable, use your twinny
1000kJ - have fun on your small wave board
1500kJ - good overhead surf
2000kJ - really good head and a half, some doubles
2500kJ - consistently overhead, frequent doubles
3000kL - lots of doubles, some bigger
3500kJ - only the good surfers are out
4000kJ - I'm just watching
5000kJ - a lot more are watching, guys with guns are getting most of the waves
8000kJ - 9' gun
10,000kJ - 10' gun or a ski
15,000kj - skis only

...

Holy shit.

that was Chris cote.

Either way, someone needs a punch in the throat.

Ah yes the spirit cave. So fleeting! So private! Except when you’re in a heat and 1.6k people are watching.

Man someone oughta take JW out and slap him.

Nick Carroll wrote: ↑

Mon Aug 13, 2018 6:39 pm

ctd wrote: ↑

Mon Aug 13, 2018 3:58 pm

It’s pretty obvious. A joule is equal to the energy transferred to an object when a force of one newton acts on that object in the direction of its motion through a distance of one metre (1 newton metre or N⋅m).

Or in other words kg * m2 / s2; where kg is the kilogram, m is the metre, s is the second

So 1000 of those

(Of course, a wave of 4ft and period of 12 seconds means nothing out of context either. It’s only because you instinctively know what that translates to in the surf relative, to other sizes and periods, that it means anything. I just measure in increments of fear)

No it's not at all obvious. A swell event spreads out across thousands of nautical miles. It strikes here and it strikes there. There's radial spread which varies enormously from swell to swell. A single swell event can span almost the entire Pacific basin. It may also focus on 200 kilometres of coastline.

Again: what does it mean? Where is that 8000 kilojoules of energy likely to be expended? Here? Over there? In what timespan? For how long?

I'll do a really rough calculation

The formula for Kinetic energy in joules is J = (mass in kg x (velocity in meters/second) squared)/2

One litre of water weighs one kg

An oceans wave with a wave length of 100m has will have a wave speed of 12 m/sec.

If we take a section of that wave to be just 100m long and one meter wide it will contain at least 100 cubic meters of water. One cubic meter of water contains 1000 liters, so thats 100,000 liters of water moving at 13m/s

So the energy for that section of one meter of the wave is (100,000kg x 13m/s x 13m/s)/2 = 8.5 million joules The wave energy is conserved, so each 1 meter wide section of that wave when it breaks will be delivering at least 8.5 million joules

I've probably fcuked up somewhere. Feel free to point out where.

Sounds good to me.

Can someone please do a similar calculation for MM throwing a good haymaker punch.
This is more the sort of thing that would fix the concept of kinetic energy in nicks mind

How’s that comparison data coming along steve? Anything yet?

Have you not been reading?

Is west east in Wales?

Cranked wrote: ↑

Mon Aug 13, 2018 7:54 pm

Nick Carroll wrote: ↑

Mon Aug 13, 2018 6:39 pm

ctd wrote: ↑

Mon Aug 13, 2018 3:58 pm

It’s pretty obvious. A joule is equal to the energy transferred to an object when a force of one newton acts on that object in the direction of its motion through a distance of one metre (1 newton metre or N⋅m).

Or in other words kg * m2 / s2; where kg is the kilogram, m is the metre, s is the second

So 1000 of those

(Of course, a wave of 4ft and period of 12 seconds means nothing out of context either. It’s only because you instinctively know what that translates to in the surf relative, to other sizes and periods, that it means anything. I just measure in increments of fear)

No it's not at all obvious. A swell event spreads out across thousands of nautical miles. It strikes here and it strikes there. There's radial spread which varies enormously from swell to swell. A single swell event can span almost the entire Pacific basin. It may also focus on 200 kilometres of coastline.

Again: what does it mean? Where is that 8000 kilojoules of energy likely to be expended? Here? Over there? In what timespan? For how long?

I'll do a really rough calculation

The formula for Kinetic energy in joules is J = (mass in kg x (velocity in meters/second) squared)/2

One litre of water weighs one kg

An oceans wave with a wave length of 100m has will have a wave speed of 12 m/sec.

If we take a section of that wave to be just 100m long and one meter wide it will contain at least 100 cubic meters of water. One cubic meter of water contains 1000 liters, so thats 100,000 liters of water moving at 13m/s

So the for that section one meter of the wave is (100,000kg x 13m/s x 13m/s)/2 = 8.5 million joules The wave energy is conserved, so each 1 meter wide section of that wave when it breaks will be delivering at least 8.5 million joules

I've probably fcuked up somewhere. Feel free to point out where.

So how big a wave would that be cranky, in Iggy feet.

Edit: reading back I'm reckoning 15+?

Magic seaweed are a bunch of spastics. That’s beyond dispute. What is still up on the air is the value and accuracy of their data

Did you not see any of the data I posted yesterday?

Actual real data.

Would you like me to interpret it for you? I thought you liked it raw.

Aren't you on holidays?

Godsave can't relax till this is settled Steve.

BA wrote: ↑

Mon Aug 13, 2018 4:08 pm

Lets nip these stupid implied comparisons in the bud BA. Waves don't have any trans or saturated fats and are much better for you, just pure unadulterated energy.