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Is the top of the buoy leaning toward the flow or away?
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Tide flow direction vs buoys
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It would be a lot easier to tell if the picture was from the opposite angle. I assume Trigger is right because it is an inshore question and those are gimmes for him. Is water welling up on the backside? That is the giveaway for a river dog like me; water surface is flat on the downstream side of an obstruction but there is usually at least a small tell on the upstream side where current pushes water up against the obstruction before splitting to go around.
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It is tethered at the bottom of the buoy. So if the water pushes on the buoy, which is above the tether point, the tether pulls on the bottom and tilts the top of the buoy to the downstream direction. So in the picture the flow is left to right. I would say it is leaning toward the direction of flow. (might be confusion of wording, but the top points to the direction the flow is going)
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I was thinking the same as nctribute so now some of us disagree who is right lol. I have looked at some around mid tide and its really hard to tell. I guess it depends some too on how the underwater section is made ive seen some cone shaped so it doesnt catch water flow. some round some square.............................soooooooooooo confusing lol
Maybe a Coastie can chime in
Maybe a Coastie can chime in
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Hmmm. now you got me thinking. The shape of the bottom and tether point could influence the direction it leans. I guess it could be doing the following.
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So maybe the answer is you do not know unless you know how the buoy is made?
But looking at this http://www.sealite.com.au/products/categories.php?cat_name=buoys
I think my first explanation is correct.
So maybe the answer is you do not know unless you know how the buoy is made?
But looking at this http://www.sealite.com.au/products/categories.php?cat_name=buoys
I think my first explanation is correct.
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The whole section of buoy exposed to water would see the force, so it can be described as a single force acting on the center of the area exposed to the water flow. Resolving to a single force helps understand how the moment will act on the buoy.
But think this shows my first explanation is true. http://www.sealite.com.au/products/categories.php?cat_name=buoys
But think this shows my first explanation is true. http://www.sealite.com.au/products/categories.php?cat_name=buoys
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Based on the link to buoys and their shown design, it is settled. Physics do not lie.I look forward to the final answer on this.
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No physics doesn't. But your drawing doesn't have the square deck that could get pushed under and tip it back the other way. The column is pretty streamlined; the deck edge is going to offer resistance. Your link is to round ones; the one in the picture is square. Doesn't defeat physics, but changes the calculation. Maybe enough to tip it in another direction. Not sure it is settled.
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Throw a bait/lure in the water and watch which way it goes = direction of current flow. I don't like to think too much about physics when I'm fishing, I have enough trouble catching fish as it is. LOL Oh and for that "What if you don't have your fishing gear with you?" question, why would you NOT have your fishing gear with you????
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No deck under water in the picture, so yes the picture above is settled. Also not seeing how you determine it is square?
Have a real hard time seeing how the flow would push the deck under and remain steady, seems like it would flop to the side and then end up as I have described, maybe not impossible, but highly unlikely. The only way the deck could change the calculation is if it moved the resultant force of the water to below the attachment point of the tether, to do that would end up with a very unstable system. The water force would have to remain perfectly inline with the tether.
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I stand corrected, in that buoy designs are out there that will lean up current, must be similar to what I showed in my second post. I just can not find a picture of one, but the link below points to their existence.
https://books.google.com/books?id=M... way will a buoy lean with water flow&f=false
Interesting read here, essentially says what I have said and it cautions that you have to know the buoy design. Bottom design can cause an up current or down current lean, but in heavy current it will always be down current. Guess there are multiple designs and seems some must use a high tether point. Would be interested to see the designs that lean up current.
So I guess using buoy lean is not fool proof way of determining current flow, unless you know the buoy.
Navel Shiphandlers Guide states that nun and can type buoys lean down current, but that lean does not alway indicate current and could be a messed up buoy.
https://books.google.com/books?id=z... way will a buoy lean with water flow&f=false
Also found a source showing how a buoy in very deep water can lean in the up current direction due to wind pushing the buoy so that the tether pulls from the opposite direction.
https://books.google.com/books?id=M... way will a buoy lean with water flow&f=false
Interesting read here, essentially says what I have said and it cautions that you have to know the buoy design. Bottom design can cause an up current or down current lean, but in heavy current it will always be down current. Guess there are multiple designs and seems some must use a high tether point. Would be interested to see the designs that lean up current.
So I guess using buoy lean is not fool proof way of determining current flow, unless you know the buoy.
Navel Shiphandlers Guide states that nun and can type buoys lean down current, but that lean does not alway indicate current and could be a messed up buoy.
https://books.google.com/books?id=z... way will a buoy lean with water flow&f=false
Also found a source showing how a buoy in very deep water can lean in the up current direction due to wind pushing the buoy so that the tether pulls from the opposite direction.
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Squinting.
Looking closer at the picture, it might not be square. I thought I saw corners but if I try to pinpoint exactly where they are I am not so certain. It is not a very clear picture. I would still expect to see water pile up, even ever so slightly, on the upstream side of any obstruction and I am not seeing that. But again that could be a matter of lack of clarity.
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Looking into it and thinking about some more, it is not necessarily the buoy design that can make a buoy lean up current. It is the tethering or mooring and depth of water. Water velocity will be the fastest near the mid depth point, so the the tether can have a big belly in it and then pull from the opposite side. Supposedly most buoys have a length of chain underneath them, so depth of water, length of chain and wind direction will determine whether this can happen.
Just like if you cast a lure quartering down wind, due to the belly in your line when you first start the retreive the lure can actually go down wind before turning and coming up wind back to you.
Just like if you cast a lure quartering down wind, due to the belly in your line when you first start the retreive the lure can actually go down wind before turning and coming up wind back to you.
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We also need to compensate for any moss growing on the North side of it...
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