Making tides

[marzoe]

Someone the other day was trying to explain to me that the best time to go fishing was two days after a spring tide or was that a neap tide or something. He said that when the difference between high and low was the least, then two days after that on a making tide. Was that on the first moon quarter or the last quarter???? I'm not confused!! MUCH. Is this true or all Bullsh*!
HELP!!!!!

[gunna]

Neap tides have less depth change between high and low - therefore less run in the water. Thats a real help in some spots.

[Dodge41]

marzoe

Your tide book will confirm the tides in relation to the moon.

At full moon the high tide is very high and ebbs out to very low low tide, meaning if you are fishing in that period the current flow will be full bore and heaps of lead required to hold bottom.
On other moons the contrast btween the height of highwater and low tide isn't as great and consequently the run is easier to fish.

Simplest way is to check your tide book and compare the fall between the two tides

Cheers
Richo

[Billo]

every spot and species will fish differently at different tides

for instance , creek mouths ....a deep water creek may have bait #held up , at the bottom of the run out , predators like flathead may sit there waiting for the baitfish .....a shallow creek mouth that holds not as much water may have bait flushed out earlier on in the drop...therefor would fish earlier in the run out .

Bait is one of the MAJOR secrets .....work out when the bait is there ....and fish that time and tide .

there is NO hard and fast rule on tides with species .....every location is different depending on the geographics

some open water species may be a little different .....ie i chase tuna along the sand banks on the second half of a run out ...as that is when the white bait gets pushed away from the shallows and the schools hone in .

another one ...Jew ...they fish well around open bars on the ebb tides when they can move in without a lot of current and ' pothole ' for baitfish held up waiting for a current to move them.....whilst around bridges and structure , they like a moving current so they can sit back in the eddies and wait for bait to come to them

another ... whiting like a incoming tide on the sand bars ...so they can move up with the water and feed on anything disturbed whilst the bar was not covered

when it comes to moon phases ....again , no hard and fast rule , although i like chasing tuna the several days before a full moon ...the baitfish move with the stronger currents on the full moon and higher tides . the tuna can ball them up easier

New moon i chase the likes of cod in the creeks ..they seem to move more openly in darkness .

EVERY location will fish differently on tide and moon

doubt i have cleared anything ;D ;D

[Jitlands]

A crap tide or receeding moon won't stop me heading out but its worth the extra effort on the peaks.

As an example
Four days befor the full moon will give you building moon, full tide and dusk all at once. Worth the effort regardless of weather conditions!

[outsiderskip]

new and full moon big tides
1/4 moons small tides

[CHRIS_aka_GWH]

and another thang....

full moon rises at dusk
new moon at dawn


best beach moon IMO is just before the rise of the new moon - the sun and moon have sucked the gutters dry & the predators use the pitch black & the first hint of light to ambush

the moon throws a lot of light - whiting love big tides but get spooky at night when there's lots of light - i've found they fish best on a full moon but when the moons underneath the earth

[webby]

This is how it all works

[Volvo]

Ferget the science mate, just remember that moon tides , quarter moon upwards to day or two after full moon fish great(this neck o the woods anyway ::))..New moon tends to fish well also but day or two either side of the new moon for day fishing, but Fish seem ta go in hiding or tuck up in bed come nightynighs :-/..
Now the prob with the bigger tides is the run so either head for shallower water, or wait fer run ta drop off a wee bit remembering that most species will feed whilst the run is up..
Cheers

[scuttlebutt]

I keep a fishing diary on my computer. With each trip I log date, location, moon phase and captures. I also get an idea of how chronic my fishing habit is. (Been to the reef 26 times so far this year)

cheers,

steve

[seaeagleweb]

id love to say i check all that stuff, but i go when i can regardless of the tide. sometimes catch and some times dont but work keeps me from getting out when the tide is right.

[gogecko]

Nice animation Webby. Also agree with Billo about different spots and species.

Now can anybody explain to me why there is 2 highs and 2 low per day?
Why is there a high on the opposite side of the earth? (see webbys gif).
Most people just says "its the moons gravitational pull" and leave it at that.
If that was true, the tidal surge would be on one side of the planet only, and not the other.

Ive been trying to work out the answer to this for years.
Are there any science experts out there?

[Duyz72]

It is not the gravitational force that is doing it, but the CHANGE in the gravitational force across the body of the Earth. The net result of this is that the Earth gets deformed into a slightly squashed, ellipsoidal shape due to these tidal forces. This happens because if we resolve the tidal forces at each point on the Earth into a local vertical and horizontal component, the horizontal components are not zero, and are directed towards the two points along the line connecting the Earth and the Moon's centers.
These horizontal forces cause rock and water to feel a gravitational force which results in the flow of rock and water into the 'tidal bulges'. There will be exactly two of these bulges. At exactly the positions of the tidal bulges where the Moon is at the zenith and at the nadir positions, there are no horizontal tidal forces and the flow stops. The water gets piled up, and the only effect is to slightly lower the weight of the water along the vertical direction.

Another way to look at it in a a 'non nerdy' way is that the gravitational force of the Moon causes the Earth to accelerate slightly towards the Moon. This causes the water to get pulled towards the Moon faster than the solid rock of the Earth on the side nearest the Moon.
On the far side, the solid Earth 'leaves behind' some of the water which is not as strongly accelerated towards the Moon as the Earth is. This produces the high tide bulge on the 'back side' of the Earth.
There are (almost) 2 tidal cycles each day because the earth rotates once every 24 hours.

The oceans are, of course, being periodically 'forced' by a number of tidal sources including the Moon and the Sun (the two dominant, referred to as the S1 and M2 'modes') In addition to the major modes, there are as many as 300 minor or 'harmonic' modes as well.

[webby]

Did you no if the Moon fell out of the sky, we would still have tides, but only Solar tides, and they would be way smaller then what we have now with no Spring or neap tides.
Though this might be of interest to some who dont no the moons full cycle.
regards

[gogecko]

Sorry duyz, you lost me there. I dont follow. Try again?
What force is causing water to bulge out on the opposite side of the earth?

[Duyz72]

OK here goes

Imagine the Earth as a round ball surrounded by a nice layer of water (which happily it just happens to be).
NOW imagine the Earth as a metal ball, and the water as mercury. #Both will be attracted to a magnet (the Moon).
So you have the moon attracting the water and the Earth at the same time.

In the pic below:
1. #There are no tides and no attraction because no moon.
2. #The attraction is strongest closest to the moon (top) and gets weaker the further you go. #So firstly the water closest to the moon is attracted making a high tide.
3. #The Earth surface closest to the moon is also attracted [but not so strongly as the water] so it too moves slightly closer. #Since the Earth is solid it all moves.
4. #The water on the opposite side is attracted the least so is left behind making another high tide.

The water at the sides is what fills the bulges making a low tide.
Since the Earth rotates once every 24 hours any point on the Earth will pass through 2 high and 2 low tidal effect areas.

This is fairly simple explanation because
a) the Earth's axis is tilted around 23.5 degrees (tides are bigger around 23.5 degrees from the Equator)
b) the Earth is spinning (causing a drag effect)
c) the moon is rotating around the Earth (so we get changes in tide times)
d) and all of this is rotating around the sun (so we get spring tides etc)

(Side note :if the Earth was on it's own and just spinning, there would be a constant high water mark at the equator, and low water mark at the poles. #This effect can be seen with the rings of saturn or the spiraling arms of a spiral galaxy)

[gogecko]

Gee Duyz, youve gone to so much effort, I do appreciate it. Im still stumped on this. I do have good knowledge of basic astrophysics, and I do mean basic.

Are these your own concepts or can you quote a source/website? Ive researched this problem before, and I never came across this concept.

heres a few points I need clarified;

"3. The Earth surface closest to the moon is also attracted [but not so strongly as the water] so it too moves slightly closer. Since the Earth is solid it all moves."
- surely you are not suggesting the moon pulls the earth off course? Your diagram seems to be saying so. The earth does not move, except around the sun. Orbit is the net result of 2 forces, and the earths gravitation is stronger than the moons. Isnt the distance between the earth and moon CONSTANT? ie Geostationary orbit....The moon does NOT pull the earth towards it resulting in a suction effect. The earth exerts a gravity force on the moon that stops the moon spinning off into hyperspace. There is a big difference.

"a) the Earth's axis is tilted around 23.5 degrees (tides are bigger around 23.5 degrees from the Equator) "
- surely the earth is only tilted at the solstice in winter and summer? In Spring and Autumn we get the equinox, and no tilt? We still get 2 tides a day.

If the moon was causing the earth to move, then we would never have been able to navigate by stars, everything in the sky would be moving. Do I understand you correctly? Im not trying to have a go at you. If you can explain this to me , I will be very grateful. As you can tell, I enjoy physics, and Ive been trying to understand this problem for years.

regards
Andrew

[Duyz72]

Pictures were a simplistic exaggeration of what happens.
A simple google search should help you out.
Here are just a few links.

http://www.faqs.org/faqs/astronomy/faq/part3/section-17.html
http://csep10.phys.utk.edu/astr161/lect/time/tides.html
http://www.mesa.edu.au/friends/seashores/tidal_zone.html
http://science.howstuffworks.com/framed.htm?parent=question72.htm&url=http://riker.ps.missouri.edu/RICKSPAGE/Moon/Tides.html
http://www.vskc.org.au/stories/two_tides.htm

Another way to explain using Axial forces.
http://www.quoddyloop.com/tides.htm

Plus the Earth 'wobbles', called the Chandler wobble, once about every 1.2 years.
http://www.crystalinks.com/earthswobble.html
http://www.sciencedaily.com/releases/2000/07/000717123812.htm

Plus every 26000 years or there abouts the axis plane does a complete rotation too.
http://www.uccs.edu/~tchriste/courses/PES105/105lectures/105lecmotions.html

Also, the moon's orbit is increasing slowly each year, eventually it will leave the gravitational pull of the Earth and go somewhere else.

So there is a lot going on just with our own Planet, let alone the rest of the Universe.

Happy Googling

[webby]

To put it simply the spinning and rotation causes gravity, which creates gravitional pull and the moon tries to pull on anything on the eaarth to bring it closer, but the earth is able to hold onto everything but the water.
Since the water is always moving the earth cannot hold on to it and the moon is able to pull on it.
Tides are not caused by the direct pull of the moons gravity, the moon is actually pulling upwards on the water while the earth is pulling downwards, but the moon has that slight advantage due to the massses of water.
The gravational force of the moon is 1 ten-millionth that of earth, but when combined with other forces such as the earths centrifical force created by its spinning you get tides.
The suns gravitional force on the earth is only 46% of the moon.
Making the moon the single most important factor for the action of tides.
Twice a month new/full the sun-moon-earth line up, which creates the greatest pull.
The rising tide is slower then the ebb.
regards

[CHRIS_aka_GWH]

just for the kids so we keep the science right....

gravity - the force between two masses, any two masses they do not have to be in motion (spinning, rotating etc) - its #an attraction - almost all objects in the universe are falling toward another - that merry dance is what started the whole spinning orbit thing

centrifugal force - the force that "throws" something outward when its in circular motion. It is if fact an inertial force - the thing thrown outward just wants to keep travelling in a straight line but its on a ride that constantly changing direction to stay in a circular path.

centripetal force - it has to be there or circular motion could not exist. For every action there is an equal and opposite reaction. It is the force that acts back toward the centre. It isn't gravity. On an aside though centifugal forces & other inertial forces are used to imitate gravity.

to put simply what webby said simply # :-?

one object (a fluid that is distendible - water) attracted by 3 others all in motion of their own & in relation to their own attraction to each other. The strongest (closest to the fluid) the earth holds the water in place the others stretch it around the earth, but the earth holds a thick layer on the side furtherest away - there is distortion at the sides. # that was simple ?!