Burnt Store Marina Update - Irma and the Seawall Collapse

[TacomaSailor]

More than five different sections of the Burnt Store Marina seawall have collapsed into the marina water. Those collapsed sections vary in length from twenty feet to 20-yards. Other sections of the seawall are still vertical but all the dirt behind them has been scoured out. I talked with a boat owner who has lived here for 15-years and endured the entire storm in a 6th floor condo overlooking his boat slip. What he told me is truly amazing!

Sunday morning not long after sunrise the water level in the marina started dropping as the NNE wind started increasing. At 11 AM the water level in the marina was at least five feet below normal. His 36-foot catamaran was resting on the marina bottom and the front third of the boat was on bare sand and mud. His boat is tied up to a 20' finger pier that extends off the seawall. A normal high tide puts the water level about two-feet below the seawall top. My slip, across the marina channel from his has eight feet of water in it at a one-foot tide level.

He walked the lenght of his seawall, about 1/4 mile, and found many large power boats high and dry on the bottom.

The NNE wind continued to blow all day and the water kept creeping further and further out of the bay. By mid-afternoon the entire marina, waterside of the seawall, had a 20 to 30 foot wide BEACH where there would normally be six to eight feet of water at a zero tide level.

He estimates the water started returning to the marina at about 2 AM Monday, long after the wind maximums had passed and the wind had backed around so it was blowing out of the WSW or dead onshore. He checked on his boat at about 3 AM and water was just starting to touch the bow.

At day break the water was just over the top of the seawall and did not rise far above that level.

But, at daybreak the seawalls were all collapsed into the bay. The working theory is that the lack of water on the bay side of the seawall allowed the weight of all the water running off the land side to gather behind the seawall and collapse it into the marina.

Many boats had tied to cleats on the seawall and lost that support when the wall collapsed. As far as I could see no boat was damaged by the wall's collapse.

The major repair problem is that cranes mounted on barges will be required to remove the damaged seawall secton and to rebuild new seawalls. However, almost every slip is filled with a boatlift rated at more than 25,000 pounds, i.e. really massive steel structures with really big pilings. Those structures block access to almost all of the wall sections, which need repair.

Safe Harbor Corporation just purchased our marina and was doing a great job of upgrading all parts of the marina. Now, they have a real job in front of them.

[Flyingriki]

Sad to hear. Beautiful marina.

[svHyLyte]

A "Seawall" or "Bulkhead" is largely designed to sustain the loading imposed by the retained soil under normal circumstances of tide et al. Seawalls are "retaining walls" of a sort but do rely on counter-pressure from the water on the seaward side to function. Sheet piles are often used for seawalls in marina's, most often with a poured concrete cap to which cleats are affixed. Such caps often, but not always, have a concrete apron extending shore-ward for several feet that serves as a sidewalk and serves to anchor the tops of the walls to resist overturning (toward the water) at low water. To be effective sheet piling needs to be fairly deeply embedded in the seafloor with deep corrugations to sustain transverse bending which is also resisted by the concrete cap and apron at the surface. The soil in the Burnt Store area is largely sand and highly permeable, meaning water readily seeps into it. When saturated, it has no shear resistance, however, so it becomes a dense, heavy "soup" or "quick-sand" that can exert enormous lateral pressure against the shore-side face of sheet piling or poured concrete bulkheads. I doubt that the seawalls at Burnt Store were designed to retain saturated shore-side soil with no water in the channels at all hence their failure is not surprising.

[Snore]

If there is a good side to this MAYBE they will dredge the channel into the marina, or move the day marks to show the hidden hump...

[CaptRory]

So sorry to hear this, but not surprised either. I enjoyed my two years there, four years ago, it presents some of the best cruising grounds in Florida at it's doorstep. Those "seawalls" were spalling off in chunks when I was there, due to rusting re-bar expansion pushing big chunks off and management would "cement" the chucks back in place for aesthetics. Their management plan pushed the liveaboards out, catering only to the condo owners, and it was in a state of decline. I'm guessing Safe Harbor got a deal on it, so may be able to upgrade on their insurance carrier. They acquired my current marina, Harborage Marina in St. Pete also and were also doing a pretty good job of improvements. At Harborage, they built a new section for mega-yachts that was getting all the love. Floating docks behind a 15 foot "breakwater" (all concrete, water on both sides with holes that allow tidal fluctuations without currents and a creek at one end) kept things comparatively calm inside from the easterly winds and wave fetch. Quite a few cleats pulled out of rotten wood on the unloved side, but no real damage has been reported and partial power has been restored. Irma had her eye right on us until the last 18 hours when she decided to slide inland just enough to put us on the right side of the wind field. We still saw 80 mph gusts but hung in behind our breakwater. I'm so grateful for the luck and for my next dock neighbor who did as prep as he could for me when I couldn't get there due to canceled flights etc. and to all my neighbors who hung in until late, looking out for each others adjustments and preps and who went back and took a walking video tour of every single dock and posted it for all of us who were waiting in angst in far away places. Thank you Thomas and all the Harborage sailers! I wish I could be there for the survival party!

[132Cat310]

Hi Tacoma, I'm sorry to hear about the damage to your beautiful marina, I'm glad all the boats survived sounds like. My wife and I have been searching for a condo in that area and recently have become interested in some properties in Burnt Store Marina. I realize you may not be in a position to know the answer to my question, and at the risk of sounding insensitive to you and your neighbors', my question is do you think the seawall repairs would be covered by insurance or might it result in significant maintenance increase or assessments to the property owners.
Thanks for any info you might have re Burnt Store Marina.

[Deltasailor]

Originally Posted by CaptRory

So sorry to hear this, but not surprised either. I enjoyed my two years there, four years ago, it presents some of the best cruising grounds in Florida at it's doorstep. Those "seawalls" were spalling off in chunks when I was there, due to rusting re-bar expansion pushing big chunks off and management would "cement" the chucks back in place for aesthetics. Their management plan pushed the liveaboards out, catering only to the condo owners, and it was in a state of decline. I'm guessing Safe Harbor got a deal on it, so may be able to upgrade on their insurance carrier. They acquired my current marina, Harborage Marina in St. Pete also and were also doing a pretty good job of improvements. At Harborage, they built a new section for mega-yachts that was getting all the love. Floating docks behind a 15 foot "breakwater" (all concrete, water on both sides with holes that allow tidal fluctuations without currents and a creek at one end) kept things comparatively calm inside from the easterly winds and wave fetch. Quite a few cleats pulled out of rotten wood on the unloved side, but no real damage has been reported and partial power has been restored. Irma had her eye right on us until the last 18 hours when she decided to slide inland just enough to put us on the right side of the wind field. We still saw 80 mph gusts but hung in behind our breakwater. I'm so grateful for the luck and for my next dock neighbor who did as prep as he could for me when I couldn't get there due to canceled flights etc. and to all my neighbors who hung in until late, looking out for each others adjustments and preps and who went back and took a walking video tour of every single dock and posted it for all of us who were waiting in angst in far away places. Thank you Thomas and all the Harborage sailers! I wish I could be there for the survival party!

We all hope that every sailor would do the right thing. Help when ever it was needed. In a harbour or at sea we are all brothers.