Above is a beautiful image from Wikimedia Commons of the Golden Gate, the narrow strait opening from the San Francisco Bay (on the left in the image above) into the vast Pacific Ocean (to the right in the image above, which was taken from the North Bay looking south towards San Francisco).  

The Golden Gate is of course spanned by the world famous Golden Gate Bridge, designed and supervised by Joseph Strauss (1870 - 1968) and completed in 1937, which is widely regarded as one of the most beautiful bridges in the world (who are they kidding -- it is undoubtedly the most beautiful bridge in the world).

The Golden Gate is about 1.7 miles wide at the point where the bridge is built across it, and its relative narrowness in comparison to the much larger bodies of water on either side of the strait means that the tides create very swift and powerful currents as the waters flood in from the ocean and then ebb back out in accordance with the tidal cycles each day (for a more detailed look at the tides and the celestial forces which influence them, see this previous post: "Moon, turn the tides . . . gently, gently away").

To understand why the tidal currents through the Golden Gate are so powerful, it may be helpful to imagine the "jet sprayer" faucet feature found on many modern kitchen sinks.  When you turn on your regular kitchen faucet, the water will come out at a certain moderate rate, but when you pull out the "jet sprayer" and depress the trigger, the water will suddenly come out with greatly increased force and pressure, even though you did not increase the water flow at the tap in any way.  Why does the water increase in power so much?  Because it is being forced through a much smaller opening (typically, through many pinhole openings, rather than through one larger faucet opening).  This is similar to the effect you get with a garden hose, when you suddenly constrict the opening with your thumb (again, the smaller gap creates an immediate increase in stream pressure, even though you did not increase the water flow at the tap in any way).

This same principle acts to greatly increase the power of the flood tide and ebb tide through the Golden Gate.  The strength of these tidal currents, and the generally cold water temperatures, helped make the notorious Alcatraz one of the most difficult prisons in the world from which to escape.  Alcatraz is pictured below, to the left of the left-hand tower in the photo as the viewer is looking at the image:

What mighty forces created this narrow gap between the San Francisco Bay and the great Pacific?  Wikipedia vaguely tells us that "San Francisco Bay is thought to represent a down-warping of the Earth's crust between the San Andreas Fault to the west and the Hayward Fault to the east, though the precise nature of this remains under study."  The entry goes on to speculate that a confluence of rivers flowing into this unexplained "down-warping" from the Great Central Valley then created the Golden Gate.

Such an explanation is typical of the kind of "hand wave" often given in place of a rigorous explanation when the conventional models have a hard time dealing with the details of the case.

In contrast, the hydroplate theory of Dr. Walt Brown offers a different hypothesis, based upon the overarching framework of Dr. Brown's comprehensive theory -- a hypothesis which finds evidence to back it up at other narrow straits around the world, and one which makes predictions about what someday will be found beneath the silt that currently blankets the bottom of the Golden Gate.

In the section entitled "Canyons" found near the end of this long webpage in his online book detailing his theory, Dr. Brown explains:
Drainage of the waters that covered the earth left every continental basin filled to the brim with water. Some of these postflood lakes lost more water by evaporation and seepage than they gained by rainfall and drainage from higher elevations. Consequently, they shrank over the centuries. A well-known example was former Lake Bonneville, part of which is now the Great Salt Lake.    
Through rainfall and drainage from higher terrain, other lakes gained more water than they lost. Thus, water overflowed each lake’s rim at the lowest point on the rim. The resulting erosion at that point on the rim allowed more water to flow over it. This eroded the cut in the rim even deeper and caused much more water to cut it faster. Therefore, the downcutting accelerated catastrophically. The entire lake quickly dumped through a deep slit, which we today call a canyon. These waters spilled into the next lower basin, causing it to breach its rim and create another canyon. It was like falling dominoes. The most famous canyon of all, the Grand Canyon, formed primarily by the breaching of what we will call Grand Lake. It occupied much of southeast Utah, parts of northeastern Arizona, and small areas of Colorado and New Mexico. [See the map on page 201 and pages 202235.] Grand Lake, standing at an elevation of 5,700 feet above today’s sea level, quickly eroded its natural dam 22 miles southwest of what is now Page, Arizona. As a result, the northwestern boundary of former Hopi Lake (elevation 5,950 feet) was eroded, releasing waters that occupied the present valley of the Little Colorado River.

With thousands of large, high lakes after the flood, many other canyons were carved. “Lake California” filling the Great Central Valley of California carved a canyon (now filled with sediments) under what is now the Golden Gate Bridge in San Francisco. The Strait of Gibraltar was a breach point as the rising Atlantic Ocean eventually spilled eastward into the Mediterranean Basin. The Mediterranean Sea, in turn, spilled eastward over what is now the Bosporus and Dardanelles, forming the Black Sea.
Note that this explanation is rigorous and detailed, it is built upon the fundamental principles of Dr. Brown's overarching theory, and that overarching theory is supported by extensive geological evidence from around the globe (see for instance"The Grand Canyon and the Great Flood," "The Ganges Fan, the Indus Fan, and the Great Flood," "The submarine canyons of California's Central Coast," "Geoids, relative gravity differences, and the deep Pacific trenches," "The bizarre 'barbed tributaries' of Marble Canyon," "Extraordinary sediment deposit from Pakistan to Bhutan supports hydroplate theory," and many others on this blog and in Dr. Brown's book).

It is also important to note that Dr. Brown's theory provides a comprehensive model from which it is possible to make predictions, and that Dr. Brown has published many such predictions in the past.  The ability to make predictions is one of the hallmarks of a true scientific hypothesis. Many of Dr. Brown's predictions have already been proven correct; others have yet to be proven.

In the case of the "downcutting" action described in the passage quoted above, in which large bodies of trapped water, left over from a global flood event, catastrophically breached, leading to the carving-out of V-shaped canyons, Dr. Brown has predicted that:
The crystalline rock under Gibraltar, the Bosporus and Dardanelles, and the Golden Gate Bridge will be found to be eroded into V-shaped notches. (This prediction, first published in 1995, was confirmed for the Bosporus and Dardanelles in 199890 and for Gibraltar in 2009.91)
In other words, Dr. Brown has applied this theory to the straits at the Dardanelles, the Bosporus, and the Straits of Gibraltar (all in the region of the Mediterranean), as well as to the Golden Gate.  He predicted in 1995 that V-shaped canyons could be found under the silt of each of these straits, because he believed that all were carved by the same type of event (the violent breaching of a narrow barrier by a large, trapped body of water). His predictions were later found to be correct in the Bosporus, the Dardanelles, and the Straits of Gibraltar.  

You can see images with cross-sections of the Dardanelles Strait in this scientific publication from September, 2012, showing the type of V-shaped notch predicted by the hydroplate theory.   Dr. Brown's prediction has yet to be proven at the Golden Gate, but perhaps it will be in the future.

The evidence would appear to suggest that the beautiful Golden Gate represents yet another strong supporting argument in favor of the hydroplate theory of Dr. Walt Brown.