Bridge Clearance Atlantic ICW

[Manateeman]

Greetings all. We have reports the bridge clearances are not getting any better on the Atlantic ICW. We are almost ready to fit the main mast and it’s an opportune time to reduce the air draft. Recent confirmed data greatly appreciated.
The manatee crew.
Captain Mark is unavailable to post.

[sailorboy1]

The bridges haven't changed

[skipmac]

Like the man said, bridges haven't changed. The spec is 65' clearance and all existing fixed bridges and new bridges are built to that spec.

There's one in Miami that missed (Julia Tuttle bridge if I recall) and occasionally some bridges will have less due to extraordinary high tides (NC a common place for this to happen due to winds blowing water up the rivers and sounds).

Otherwise I would plan for a 62-63' clearance max.

[Shrew]

Here is a 2019 Coastal Vulnerability Assessment for Atlantic Beach Florida.

https://www.coab.us/DocumentCenter/V...--061219-Final

I think you have a long way to go before you need to be worried.

[BillKny]

Originally Posted by Manateeman

Greetings all. We have reports the bridge clearances are not getting any better on the Atlantic ICW.

Of course they aren't getting any worse either...

This question has always baffled me.

As the owner of a boat with a 67 foot air draft, we never even consider the ICW. Even if we COULD fit, we'd infinitely prefer the ocean route.

I would think that any boat that would carry a 65+ foot mast would be capable of ocean voyages? On the other hand if you think the ICW is a cool trip, a sailboat of that size just seems kind of the wrong choice....

[Vasco]

The Julia Tuttle is about 56 ft. The other low one is at the southern end of the Alligator Pungo Canal. About 64 ft I think.This one can be bad as the water depth is dependent on the wind, not tidal. Have seen southbound boat turn around here and head back to the Albemarle to head south.

[JebLostInSpace]

Unfortunately I don't have exact numbers or even exact bridges for you, but I do recall a run of several in a row between Fort Pierce and the Georgia border where the high water marks on the bridges were consistently about 63' on the tide boards.

As for why you'd take a big sailboat through the ICW: In my case I did it a whole bunch because I singlehand, and the safe channels on the east coast are often too far apart to reach in an amount of time I could stay awake. I'm not keen on sleeping while singlehanding, especially in coastal waters with fishing boats out at all hours, so I went inside.

There are also ports you may want to visit, where the desirable dock/mooring/anchorage are through an ICW bridge. Charleston, St Augustine, and Fort Pierce come to mind.

[GreenWave]

Originally Posted by JebLostInSpace

Unfortunately I don't have exact numbers or even exact bridges for you, but I do recall a run of several in a row between Fort Pierce and the Georgia border where the high water marks on the bridges were consistently about 63' on the tide boards.

As for why you'd take a big sailboat through the ICW: In my case I did it a whole bunch because I singlehand, and the safe channels on the east coast are often too far apart to reach in an amount of time I could stay awake. I'm not keen on sleeping while singlehanding, especially in coastal waters with fishing boats out at all hours, so I went inside.

There are also ports you may want to visit, where the desirable dock/mooring/anchorage are through an ICW bridge. Charleston, St Augustine, and Fort Pierce come to mind.

Not looking to pick a fight, but if one singlehands then why buy a bigger boat that limits your options?

[hpeer]

Originally Posted by Manateeman

Greetings all. We have reports the bridge clearances are not getting any better on the Atlantic ICW. We are almost ready to fit the main mast and it’s an opportune time to reduce the air draft. Recent confirmed data greatly appreciated.
The manatee crew.
Captain Mark is unavailable to post.

How tall are you now?

Was there something more specific that prompted your question?

[Manateeman]

We would like to thank Shrew, Vasco and Lost in Space.
Dear Mr. Green Wave. The manatee crew built this vessel and many others. We did not “buy” it. Any one of the crew of licensed professional mariners are quite capable of sailing this vessel so not to worry.
Mr. H.peer. No one on board is willing to provide their exact displacement, which hovers around a ton, nor their length. We are contemplating two rigs. A tall ocean and a short ICW. In our original post, you can see that the mast has not been stepped and the length could be adjusted. Not sure of what you refer to as “how tall are you”.
Dear Skipmac and Sailor boy. We have it from several reliable sources that a vessel with 65’ air draft will not pass under some ICW bridges. Thus our question.
The manatee crew would like to amend the post to add the question...is there a small camera which could be placed at the masthead to check clearance.
Happy trails to all.
The manatee crew.

[sailorboy1]

So if i understand the question it is:

We dont believe the official listed heights of the ICW bridges because we heard from some unnamed person that some may be less. So which expert here knows the true height of the bridges that we can instead believe in.

The bridges have not changed heights. The official heights are the minimum clearance under them for the conditions designed. The height may be more or less under different conditions. No one can tell you what the height may be when you go under the bridge. It is up to boaters to understand how the conditions may effect the height and to adjust their travel as needed.

In the last 4.5 years i have been under 90+% of the AICW bridges. I have never seen a height board say less than 62’. That doesn't mean that during a period of high rain runoff with a high tide and wind against the current that it is possible that could be less. Because in the Fall after a hurricane or TS has passed through it easily could happen.

[kmacdonald]

I went all the way down the ICW last fall. There were bridges that had 63.5 foot clearance. I wouldn't do the ICW with air draft above 63 feet unless I had time to wait for low tides. Miami has a 55 foot bridge.

[JebLostInSpace]

Originally Posted by GreenWave

Not looking to pick a fight, but if one singlehands then why buy a bigger boat that limits your options?

My air draft is only 59' so my options aren't limited. OP isn't primarily singlehanding, but it's still a situation that may occur and I thought I'd point it out.

Even though I'm not limited by height, I wouldn't think it unreasonable to get as big a boat as one can afford and handle, even as a single-hander. Bigger boats are usually more comfortable and safer - as a general trend with plenty of variation from other factors.

I'll also just throw out that Hatteras is a big enough PITA that even a well-crewed boat may reasonably choose to go inside through that stretch. Especially if schedules get involved. As I recall the bridges up there were pretty reliably the full 65 ft, but perhaps someone with a more recent memory of that area will chime in.

[smj]

On our recent trip up the ICW it was the norm to see bridge clearance’s below 65’ at high tide rather than the exception in Florida. We ran across a couple of bridges that had a 63’ clearance and it wasn’t high tide. We also weren’t dealing with a king tide. I’m pretty sure the bridges aren’t sinking and I’m also pretty sure the water is at a higher level now than when the bridges were built.

[GreenWave]

Originally Posted by smj

On our recent trip up the ICW it was the norm to see bridge clearance’s below 65’ at high tide rather than the exception in Florida. We ran across a couple of bridges that had a 63’ clearance and it wasn’t high tide. We also weren’t dealing with a king tide. I’m pretty sure the bridges aren’t sinking and I’m also pretty sure the water is at a higher level now than when the bridges were built.

No doubt water levels are rising. This is becoming very problematic for southeast FL. Also, if I were a betting man I would be putting my money on bridges sinking as opposed to getting higher. The latter doesn't compute. Having said that, the height under any bridge is never truly known until you get there.