Wednesday, April 2, 2014
4/2/14 Report - How East Winds Work Compared to Northeasters, The First British Sea Dog & A Civil War Prison Camp
Written by the TreasureGuide for the exclusive use of treasurebeachesreport.blogspot.com.
Yesterday I showed how a Nor'easter affects a beach. Today I'll show how that differs from a situation where the waves are hitting more from the East rather than the Northeast. There are some very important differences.
If you didn't read yesterday's post, I'd recommend doing that before reading this one.
I'll start with the same photo that I used yesterday when I showed how a Nor'easter works. Since this beach already has a long cut, we'll assume that cut was created earlier but now the wind has switched around and is coming from the East, as shown by the long black arrow.
Notice in the picture the wave orientation and direction of the Nor'easter, as shown at the top right of the picture. That could be the situation that existed when the cut was created.
Below that is shown how the wave fronts would be more parallel to the beach and cut after the wind has changed and is coming from the East. The straight black line shows how a wave would be oriented, and the long black arrow shows its direction as it hits the beach.
Assume that a single wave, indicated by the long black arrow, comes up the beach and hits the bottom of the cut. It loses speed and stops and reverses direction, with the water then returning back down the slope.
With a Nor'easter, the water hits from the north, moves south along the beach, and then arcs down and back into the water.
When the waves are hitting directly at the beach, though, the water goes up the slope and then retreats straight back down the slope. But what happens then? Another wave arrives to hit the retreating water from the first wave at some point. That creates a dead area where most materials that were being moved by the water will be dropped.
The short black arrow shows water from the first wave retreating, and the red arrow shows the second wave coming in. The yellow star between the black and red arrow is where the incoming wave hit the retreating wave. That is the dead zone where the flow from both waves halts and where material is dropped.
Of course this happens with every wave.
The yellow star at the base of the cliff shows where the momentum of the first wave stopped before it began to retreat down the slope.
This is very different from what happens during a Nor'easter in which there is a nearly constant flow along the beach front as the water approaches from the Northeast, arcs up the beach and then back down to the South and back into the water. With a Nor'easter, instead of each wave clashing into the previous wave as it returns down the slope, there is a much more uninterrupted flow which keeps its momentum going and therefore carries more material.
Remember the trigger points that I talked about back probably a couple of weeks ago. Those are very important and you probably won't learn about them anywhere else.
It takes a certain amount of water flow to pick up and move different objects. It takes more flow to pick up some objects and some types of objects are dropped more quickly than others. It will take less flow to pick up and move sand, for example, than rocks. It will also take more flow to keep rocks moving (unless they are round). And the sand will not drop out as quickly as the rocks.
The point is that different types of objects will be picked up and dropped at different places depending up on the flow of water and the characteristics of the objects. That is an important fact.
In the above picture I pointed out two places where objects will be dropped out (yellow stars). Very movable objects such as sand or small shells that are carried up to the cliff will drop out there, and many of the objects that are being brought back down the cliff by the retreating water will be dropped where the retreating water clashes with the next incoming wave as the flow comes to a quick halt. This is how a coin line can be created.
The location on the slope where the incoming wave hits the retreating wave will change as the waves change size and as the tides change. If the swells and waves do not change, the clash point will be higher on the beach at high tide and lower at low tide.
This illustration assumes that the water is not hitting the cliff with force, but is stopping near the base of the cliff. In that case, the movement of water between the top and bottom star is relatively slow and light material, such as sand, will be dropped there.
The situation changes a little if the waves are hitting the cliff with force. Then the cliff face will fall and more sand and other material will be moved by the retreating water until it is dropped, very much of it when it hits the next incoming wave.
If the tide is high and the waves high, so that the water goes up over the cliff, the cliff will be flattened out in a hurry, and a sloped mushy beach-front created.
I think you can now see that there is a big contrast between what happens during a Nor'easter and an Easter. Of course I've left out a number of factors to keep it simple, but the main thing is that you have a much less interrupted and therefore more forceful flow along the beach with a Nor'easter.
The first of the British Sea Dogs was John Hawkins. After learning from the Portuguese that the Spaniards in Hispaniola would buy as many slaves as they could get, in 1562 Hawkins sailed to Sierra Leone where he bought and captured three hundred slaves to take to the New World. That was his first trip, and it was profitable as he received sugar, ginger, hides and pearls.
He made a second trip to the New World in 1564, The second trip was a little more problematic, but he made trades and took time to learn all he could about the Caribbean and Spanish colonies.
On his third trip, in 1566, he was injured in Africa and then when arriving on the Spanish Main in South America, he found that the Spanish were under instructions to not trade with the English. Nonetheless he managed to make the trades before having his ships damaged by a hurricane. Then the Spaniards would not allow him to get provisions and refit and he was attacked, leaving only two of his five ships to return to England. Most of his men were captured by the Spaniards, but he and Francis Drake (who sailed with Hawkins) both escaped. Drake, in revenge, became a privateer.
That story is told in the West Indian History book that I referenced the other day as well as many other places.
Here is a link to a good article about a dig about the Civil War prison camp, Asylum.
On the Treasure Coast the tides aren't quite as big today as yesterday, but still bigger than usual.
The surf is around three feet, and it will be about that for a few days.
Beach conditions remain poor for finding old things, but you can still find modern items.