Caution!  Charted bridge clearances are often "design" clearances.  Many older 
bridges have subsided.  Two notable examples in my area are the East Pass 
Bridge at Destin, FL and the Navarre Beach Bridge.  Most locals believe the 
actual clearances are a foot or so less than that stated on the charts.

Also watch for wires and cables hanging under bridges.

Another idea for the stout of heart, don't pass through the charted channel 
clearance.  Pass under 1 or 2 spans on one side of the channel passage.  
Because of its wider horizontal clearance, the channel passage will usually 
have a larger girder supporting the span.  To the left or right, the shorter 
spans will have smaller girders or concrete "Tees".  Often there is more 
vertical clearance in these spans than the channel passage.  Of course, there 
may not be enough depth or width for passage.  I don't recommend this unless 
you really, really know what you're doing.

Years ago, there were a couple of tall racing sloops in New Orleans.  To pass 
under the I-10 bridge at Slidell, LA, they routinely passed one span from the 
channel clearance.

Look at this picture of the Navarre Beach Bridge:

<http://www.google.com/imgres?q=navarre+beach+bridge&num=10&hl=en&biw=1366&bih=596&tbm=isch&tbnid=AH5vUSygQ54BEM:&imgrefurl=http://www.wunderground.com/wximage/jennjeff1/4429%3Fgallery%3D&docid=9lCQM_FWA4qVvM&imgurl=http://icons-ak.wunderground.com/data/wximagenew/j/jennjeff1/4429-800.jpg&w=800&h=464&ei=7feXUIXXEoj1ygGGqoDoBA&zoom=1&iact=hc&vpx=551&vpy=312&dur=78&hovh=171&hovw=295&tx=133&ty=129&sig=113816113435251940368&page=5&tbnh=135&tbnw=224&start=88&ndsp=24&ved=1t:429,r:70,s:20,i:345>

The charted clearance is 50 feet.  The best I've seen on the clearance board is 
49'2" at low tide.  However, according to one local sailor, there is 51 feet of 
clearance two spans to the south of the channel (see the first reply here:  
http://forums.hunter.sailboatowners.com/showthread.php?t=45201).  That would be 
the first span closest at the end of the blue girder support.  Not for the 
faint hearted!!  The admiral has threatened me with grievous bodily harm should 
I attempt it!!

Dennis C.
Touche' 35-1 #83
Mandeville, LA





>________________________________
> From: Andrew Burton <a.burton.sai...@gmail.com>
>To: cnc-list@cnc-list.com 
>Sent: Monday, November 5, 2012 11:10 AM
>Subject: Re: Stus-List Bridge clearance issues
> 
>
>Another thing to take into account: how wide does the boat get when you heel 
>her over 25 degrees? Check the horizontal clearance on the bridge. It should 
>be on the chart. 
>Joel, bridge height is measured from mean high water.
>Cheers
>Andy
>
>
>On Mon, Nov 5, 2012 at 12:04 PM, Richard N. Bush <bushma...@aol.com> wrote:
>
>Joel;  you're correct about the mast height, (50 ft, plus a three foot 
>antenna, I added a foot or so for the sphincter factor); the bridges I am 
>looking at are rivers, so there's no tide as such; they do have a "mean low 
>water mark" which is typically summer pool stage; thanks 
>>
>>
>> 
>> 
>>Richard
>>1987 33-II
>> 
>>
>>Richard N. Bush Law Offices 
>>235 South Fifth Street, Fourth Floor 
>>Louisville, Kentucky 40202 
>>502-584-7255
>>
>>
>>-----Original Message-----
>>From: Joel Aronson <joel.aron...@gmail.com>
>>To: cnc-list <cnc-list@cnc-list.com>
>>Sent: Mon, Nov 5, 2012 11:54 am
>>Subject: Re: Stus-List Bridge clearance issues
>>
>>
>>Richard, 
>>
>>
>>You must have a large antenna.  My 35/3 has a mast height of 50.5 feet 
>>according to sailboatdata.com.  (No dimension for your boat).  Your mast 
>>looks to be about 2 feet shorter than mine.
>>
>>
>>Aren't the readings at Mean Low tide?  Have you factored that in?
>>
>>
>>Can you rig a temporary adjustable forestay?  24 degrees is a lot of heel!  
>>Maybe 10 large friends on the rail?
>>
>>
>>
>>On Mon, Nov 5, 2012 at 11:40 AM, Richard N. Bush <bushma...@aol.com> wrote:
>>
>>Hi all; I am planning for a trip (next summer) I will have to pass under a 
>>bridge with a 50 ft clearance; I calculate that the mast is 55 ft from 
>>water including all antennae, etc;  I have come up with a chart showing that 
>>I will have to heel the boat 24.4 degrees to clear a 50 ft span; and 35.9 
>>degrees to clear a 45 ft span; (I had to have help from an engineer friend!); 
>>now, what is the best way to get the boat to 24.4 degrees and keep it there 
>>long enough to get under the bridge?
>>>
>>>
>>>Richard
>>>1987 33-II
>>>
>>> 
>>> 
>>>Richard N. Bush Law Offices 
>>>235 South Fifth Street, Fourth Floor 
>>>Louisville, Kentucky 40202 
>>>502-584-7255
>>>
>>>
>>>_______________________________________________
>>>This List is provided by the C&C Photo Album
>>>http://www.cncphotoalbum.com/
>>>CnC-List@cnc-list.com
>>>
>>>
>>
>>
>>
>>-- 
>>Joel 
>>301 541 8551
>>
>>_______________________________________________
This List is provided by the C&C Photo Album http://www.cncphotoalbum.com 
CnC-List@cnc-list.com 
>>_______________________________________________
>>This List is provided by the C&C Photo Album
>>http://www.cncphotoalbum.com
>>CnC-List@cnc-list.com
>>
>>
>
>
>-- 
>Andrew Burton
>61 W Narragansett Ave
>Newport, RI
>USA 02840
>http://sites.google.com/site/andrewburtonyachtservices/
>phone  +401 965 5260
>
>_______________________________________________
>This List is provided by the C&C Photo Album
>http://www.cncphotoalbum.com
>CnC-List@cnc-list.com
>
>
>
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