Tenn-Tom Highway 43 bridge height at Jackson, AL

[rgano]

I am doing some research for a friend with a 56-foot tall mast heading upstream from Mobile. The COE chart shows a vertical clearance at the Highway 43 bridge of 52 feet, but examining the vector chart allows me to see a bridge diagram with a table showing height of low steel of around 81 feet. Wondering why these differences and if anybody has actually been through there recently and had a look at the bridge gauge? I wish I had paid more attention the several times I passed through there in the past.

 

[rgano]

This fellow is not going very far north, so no need to worry over the clearances farther up.

 

[BandB]

I am doing some research for a friend with a 56-foot tall mast heading upstream from Mobile. The COE chart shows a vertical clearance at the Highway 43 bridge of 52 feet, but examining the vector chart allows me to see a bridge diagram with a table showing height of low steel of around 81 feet. Wondering why these differences and if anybody has actually been through there recently and had a look at the bridge gauge? I wish I had paid more attention the several times I passed through there in the past.

Are you referring to the Hwy 43 bridge on the Black Warrior at RM 218.7 or the Hwy 43/69/13/I-359 at 338.9? Guess trying to make sure we're talking about the same bridge before responding.

 

[Alaskaflyer]

"Low steel" height on COE supplementals is usually given as elevation above sea level, while vertical clearance is given as height in feet above waterline at normal pool, with any 1% flood or other additions sometimes included. Hope this helps.

 

[Alaskaflyer]

Are you referring to the Hwy 43 bridge on the Black Warrior at RM 218.7 or the Hwy 43/69/13/I-359 at 338.9? Guess trying to make sure we're talking about the same bridge before responding.

There's also the US 43 bridge on the lower Tom near Jackson.

 

[Alaskaflyer]

Is it this one? If so, the normal pool is right at MSL, so clearance and elevation are the same. 80 feet and inches at center but the left and right spans are 74-75 feet.

https://www.sam.usace.army.mil/Port...e Reference 12B.pdf?ver=2020-02-24-145812-593

 

[BandB]

Is it this one? If so, the normal pool is right at MSL, so clearance and elevation are the same. 80 feet and inches at center but the left and right spans are 74-75 feet.

https://www.sam.usace.army.mil/Port...e Reference 12B.pdf?ver=2020-02-24-145812-593

To be adjusted by water level above or below 0. Did the title originally say Jackson, AL and I totally missed it or was it changed to that?

 

[Alaskaflyer]

To be adjusted by water level above or below 0. Did the title originally say Jackson, AL and I totally missed it or was it changed to that?

ROFL. Not sure but maybe changed. I was originally trying to think of where US 43 crosses the Tenn-Tom and then reread his post.

 

[rgano]

Are you referring to the Hwy 43 bridge on the Black Warrior at RM 218.7 or the Hwy 43/69/13/I-359 at 338.9? Guess trying to make sure we're talking about the same bridge before responding.

Mile 89.9, and no, the tile was perfect the first time so no need to change it.

The confusion is over the COE chart which says 52' Vertical Clearance Open. 52' referenced to what?

And now that I know the COE diagrams on my vector charts and the clearance tables therein reference MSL the 81', clearances there clash mightily with the COE chart of 52' because MSL before the Coffeeville Dame and nominal river stage are pretty close.

 

[Alaskaflyer]

You may have this already, but here is a link to all of the COE charts including bridge references for the Black Warrior-Tombigbee system i.e. the "lower" 217 miles.

https://www.sam.usace.army.mil/Miss...r/BWT-Alabama-Rivers-Navigation/River-Charts/

 

[Alaskaflyer]

Mile 89.9, and no, the tile was perfect the first time so no need to change it.

The confusion is over the COE chart which says 52' Vertical Clearance Open. 52' referenced to what?

And now that I know the COE diagrams on my vector charts and the clearance tables therein reference MSL the 81', clearances there clash mightily with the COE chart of 52' because MSL before the Coffeeville Dame and nominal river stage are pretty close.

Hmmm...

At 89.9, the COE charts I see show a railroad lift bridge. The bridge reference shows a closed and open clearance, but neither are 52'

 

[rgano]

Hmmm...

At 89.9, the COE charts I see show a railroad lift bridge. The bridge reference shows a closed and open clearance, but neither are 52'

COE Chart LBLKWR34? Or some other version of a COE? %2' big as a bull's.....

 

[Alaskaflyer]

COE Chart LBLKWR34? Or some other version of a COE? %2' big as a bull's.....

I don't have access to my usual electronic nav charts where I'm currently at, but the online PDF's from USACoE for the river system:

https://www.sam.usace.army.mil/Port...n/BWT/Nav Charts 2013/Navigation Chart 12.pdf

https://www.sam.usace.army.mil/Port...e Reference 12A.pdf?ver=2020-02-24-145820-687

I also looked at it on Navionics and it shows 86' open and 40' closed.

Upstream at mile 92.8 is where it shows the twin spans of Hwy 43, discussed in post number 6 above.

 

[BandB]

Mile 89.9, and no, the tile was perfect the first time so no need to change it.

The confusion is over the COE chart which says 52' Vertical Clearance Open. 52' referenced to what?

And now that I know the COE diagrams on my vector charts and the clearance tables therein reference MSL the 81', clearances there clash mightily with the COE chart of 52' because MSL before the Coffeeville Dame and nominal river stage are pretty close.

I can't believe I missed the location in the title.

Now, I don't know about the charts you're looking at but I've heard in the past of people finding the charts they had were at maximum height, basically up to flood stage, so about 25' more and that would tie to the discrepancy here between the 52' and the 79.48 on the Army Corps of Engineer PDF's. This is the only explanation I have. All I remember personally is that every bridge we went under on the Mobile River and the Tombigbee, wasn't just tall, but was extraordinarily high. Note this bridge is not over the Tenn Tom, but over the Tombigbee. It is on the Tenn Tom itself, once the rivers split, that the bridges are more what we're use to in the 50-60' range.

However, as my air draft was in the 20' range, I didn't check any of them.

 

[rgano]

I can't believe I missed the location in the title.

Now, I don't know about the charts you're looking at but I've heard in the past of people finding the charts they had were at maximum height, basically up to flood stage, so about 25' more and that would tie to the discrepancy here between the 52' and the 79.48 on the Army Corps of Engineer PDF's. This is the only explanation I have. All I remember personally is that every bridge we went under on the Mobile River and the Tombigbee, wasn't just tall, but was extraordinarily high. Note this bridge is not over the Tenn Tom, but over the Tombigbee. It is on the Tenn Tom itself, once the rivers split, that the bridges are more what we're use to in the 50-60' range.

However, as my air draft was in the 20' range, I didn't check any of them.

Like you, I never worried about it with a 26-foot masthead height, but my friend with a 56-foot mast on his blowboat and running north from Mobile to evade Zeta wanted to know for sure. Thanks for your comments.

 

[Alaskaflyer]

Well, FWIW, the USCG note indicates the railroad bridge operates in open-to-vessels position unless a train is passing

 

[rgano]

Well, thanks guys. I think we can put this one to bed with the understanding that my electronic COE chart is wildly misleading on at least one if not both the Jackson, AL (TT mile mark 91 plus/miles a mile or so) bridges. I feel safe in telling my friend that he can get under them with his 56-foot mast if he elects to run that far north.