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  #1  
Old 10-04-2006, 08:58 PM
ntcrawler ntcrawler is offline
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Shortest distance between Alcatraz Island and shore

what is the shortest possible distance between Alcatraz island an the mainland up in Northern California?
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  #2  
Old 10-04-2006, 09:04 PM
Mangetout Mangetout is online now
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Just measured it on Google Earth and I get 0.94 miles from the southern tip of the island to the nearest tip of a wharf in almost completely southerly direction.
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Old 10-04-2006, 09:10 PM
Mangetout Mangetout is online now
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Meanwhile, I'll try to answer your actual question....
Again, from Google Earth:

2.92 miles to the tip of Peninsula Point (to the NW)
2.57 miles to Yellow Bluff (West)
1.67 miles to the southern tip of Angel Island, but that;s not the mainland.
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  #4  
Old 10-04-2006, 09:14 PM
yabob yabob is online now
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Quote:
Originally Posted by ntcrawler
what is the shortest possible distance between Alcatraz island an the mainland up in Northern California?
Actually, only a bit over a mile to the North Beach / Fort Mason area:

http://maps.google.com/maps?q=alcatr...3&om=1&iwloc=A

But the currents are nasty, the water is cold, and there's a vicous undertow. Any sharks off Alcatraz are mostly lemon sharks, which are not man eaters. When you succumb to the other factors, they might scavenge your body, though.
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  #5  
Old 10-04-2006, 09:26 PM
Shagnasty Shagnasty is offline
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People do make the swim pretty often though for sport. The water temperatures I have found look like are in the upper 50's F. I have swam in water a little colder than that in Maine and although it felt mega-cold, I wasn't freezing to death even just standing out there.

http://home.pacbell.net/leewaysf/swimvent.html
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  #6  
Old 10-04-2006, 09:28 PM
ntcrawler ntcrawler is offline
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I don't intend to swim it, I just wanted to confirm some numbers. Call it a wager What about to the east?

Sharks that far north? Yikes!
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  #7  
Old 10-05-2006, 02:06 AM
PBear42 PBear42 is offline
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The number I 've usually seen is 1-1/4 miles. See, e.g., the Bureau of Prisons' website on Alcatraz. Don't know how far it would be east (towards Berkeley), but much further and nowhere near the shortest distance.

BTW, as mentioned on the BOP site, the sharks aren't man-eating type, and never were. Also, bear in mind that fish actually do better the further north you go, as the water holds more oxygen. That's why the leading commercial fisheries in the Northern Hemisphere are near Alaska and Newfoundland.
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  #8  
Old 10-05-2006, 10:42 AM
yabob yabob is online now
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The number I 've usually seen is 1-1/4 miles. See, e.g., the Bureau of Prisons' website on Alcatraz. Don't know how far it would be east (towards Berkeley), but much further and nowhere near the shortest distance.
Due east is Treasure Island, about 2 miles distant. Not mainland, but the same remarks apply as to Angel Island. TI is connected to the mainland by the Bay Bridge (Angel Island has Ferry Service). If you missed either, it would be a long haul to the shoreline around Emeryville / Berkeley. Might help if you found the Berkeley Pier.

Sharks - I based my squib about lemon sharks on the FAC at the Alcatraz site, which mentioned they aren't maneaters, but scavengers. Looking up stuff about lemon sharks, though, I wonder what in the heck they are doing in SF Bay (besides freezing their dorsal fins off). It IS awful far north for them, oxygenated water or not - most of their range is tropical and subtropical waters.
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Old 10-05-2006, 10:51 AM
Bryan Ekers Bryan Ekers is online now
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Quote:
Originally Posted by yabob
Looking up stuff about lemon sharks, though, I wonder what in the heck they are doing in SF Bay (besides freezing their dorsal fins off).
They have to keep swimming or they turn into this.
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  #10  
Old 10-05-2006, 10:59 AM
ralph124c ralph124c is offline
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So , how hard of s wim to freedom is this? How many convicts 9in decent shape) could have pulled off a swim off the rock? I'm actually surprised that there weren't more attempts.
Anybody know how many tried and drowned?
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  #11  
Old 10-05-2006, 11:00 AM
DrDeth DrDeth is offline
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There is a great epi of Mythbusters on this.
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  #12  
Old 10-05-2006, 12:31 PM
wevets wevets is offline
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Quote:
Originally Posted by yabob
Sharks - I based my squib about lemon sharks on the FAC at the Alcatraz site, which mentioned they aren't maneaters, but scavengers. Looking up stuff about lemon sharks, though, I wonder what in the heck they are doing in SF Bay (besides freezing their dorsal fins off). It IS awful far north for them, oxygenated water or not - most of their range is tropical and subtropical waters.
I suspect someone's made a goof. Some of the most common sharks in San Francisco Bay are leopard sharks and sixgill sharks. Thresher sharks also visit the Bay. In three years of whale watching out of San Francisco and four years of teaching in local national parks and marine sanctuaries I've never heard of nor seen a lemon shark in San Francisco Bay or the surrounding waters including the Gulf of the Farallones and other local estuaries such as Tomales Bay, Drake's Estero, etc.

Lemon sharks occur from Baja California south, but not this far north.
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  #13  
Old 10-05-2006, 12:38 PM
garygnu garygnu is offline
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Quote:
Originally Posted by wevets
...Lemon sharks occur from Baja California south, but not this far north.
They must be avoiding California's tough Lemon Law.
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  #14  
Old 10-05-2006, 01:08 PM
Jayrot Jayrot is offline
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Although surely they rarely enter The Bay, there is a huge population of Great White Sharks in that area off the coast (near the Farallons). In fact, the area is known as the Red Triangle. It's estimated that of all documented great white shark attacks on humans, more than half have occurred within the Red Triangle.
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  #15  
Old 10-05-2006, 01:23 PM
Edward The Head Edward The Head is offline
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The Alcatraz Invitational says the swim is 1.25 miles. I've never heard of any attacks from sharks during the swim. There are actually a couple of swims thoughout the year. If I lived on that side I'd think about doing it.
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  #16  
Old 10-05-2006, 03:46 PM
yabob yabob is online now
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Quote:
Originally Posted by wevets
I suspect someone's made a goof. Some of the most common sharks in San Francisco Bay are leopard sharks and sixgill sharks. Thresher sharks also visit the Bay. In three years of whale watching out of San Francisco and four years of teaching in local national parks and marine sanctuaries I've never heard of nor seen a lemon shark in San Francisco Bay or the surrounding waters including the Gulf of the Farallones and other local estuaries such as Tomales Bay, Drake's Estero, etc.

Lemon sharks occur from Baja California south, but not this far north.
That sounds more reasonable.
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Old 10-05-2006, 09:15 PM
633squadron 633squadron is offline
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Quote:
Originally Posted by Edward The Head
The Alcatraz Invitational says the swim is 1.25 miles. I've never heard of any attacks from sharks during the swim. There are actually a couple of swims thoughout the year. If I lived on that side I'd think about doing it.
Bunches of people make the swim every year. The Escape From Alcatraz triathlon starts near the island; you jump off a tour boat (I swear I am not making this up). The local swim club down at Aquatic Park (name escapes me) sponsors many swims. Some people do it several times a year.

I have never heard of any shark attacks in the Bay. For that matter, shark attacks along the Pacific Coast from Marin down to Monterey are rather rare. I've only heard of 3 in the 24 years I've lived in the SF Bay Area.

The real problems are cold and current.

The water hovers in the high 50s even in summer. I swam at Aquatic Park this summer in my triathlon (5mm) wet suit, for about 45 minutes. At the end I was cold enough that I could use my hands all that well, a sure sign of impending hypothermia.

Some people swim at Aquatic Park or do triathlons or swims without wetsuits. I'm not sure what this proves.

The currents are very tricky. If you don't know what you're doing, you'll be drawn way off course and spend 1 1/2 hours doing what should be a 30-50 minute swim. My tri club does a lot of training and review up there before each EFA.
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  #18  
Old 10-06-2006, 02:11 AM
PBear42 PBear42 is offline
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It's the Dolphin swim club.
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  #19  
Old 10-06-2006, 12:10 PM
Edward The Head Edward The Head is offline
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Quote:
Originally Posted by 633squadron

Some people swim at Aquatic Park or do triathlons or swims without wetsuits. I'm not sure what this proves.
Mostly it proves that some swimmers like to be pure and not use something that will give extra warmth. I'd do something that short without, but I tried a 7.5 mile swim last year in 60 degree water and couldn't make it.
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  #20  
Old 10-06-2006, 08:31 PM
wevets wevets is offline
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Quote:
Originally Posted by Jayrot
Although surely they rarely enter The Bay, there is a huge population of Great White Sharks in that area off the coast (near the Farallons). In fact, the area is known as the Red Triangle. It's estimated that of all documented great white shark attacks on humans, more than half have occurred within the Red Triangle.

You're right - white sharks (or, if you like, Great White Sharks!!! it has to have exclamation points) very rarely enter SF Bay. They are very picky about conditions and likely to avoid the Bay's lower salinity, turbid waters. It's extremely rare to find one in the Bay itself. You're very safe from sharks swimming in SF Bay.
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