Seawall Collapsed

[1fer]

Hello cruisers,

I have a particular situation on a 100' seawall in Florida. The short story is that the seawall has completely collapsed into the waterway! The seawall was showing signs of deterioration and work was done to fix the visible issues. I contacted several seawall repair companies back in Sept-Oct 2020 and none of them provided information that would lead me to believe the seawall needed emergency action and all of these companies suggested similar scope of work/repair/price, so I thought everything checked out.

Later after the work was done, the dock was rented out to a big yacht (95' Ferretti) and the seawall started to show surface cracks on the cap not too long after that.

Looking at the pictures from the dock/security footage, I noticed the yacht was tied directly to the seawall itself so I am trying to determine if tying a boat this big/heavy to a seawall could potentially be a cause of an incident like this?

I was also able to gather some information regarding the weight of this yacht and it is in the 200,000 pound range.

The way I see this is tying a 200,000 pound yacht to a 50 year old seawall is like landing a helicopter in the roof of a an old house just because the roof is a flat surface doesn't mean its not going to brake apart.

Any advice/engineering perspective would be greatly appreciated.

Thank you

[LittleWing77]

Sorry to say, 1fer, but I hope that 95-foot yacht's dock rental fees will be sufficient to cover your seawall reconstruction costs, because I'm speculating that your insurer won't...?

[StuM]

Originally Posted by 1fer

Later after the work was done, the dock was rented out to a big yacht (95' Ferretti) and the seawall started to show surface cracks on the cap not too long after that.

Looking at the pictures from the dock/security footage, I noticed the yacht was tied directly to the seawall itself so I am trying to determine if tying a boat this big/heavy to a seawall could potentially be a cause of an incident like this?

You don't say how the seawall was constructed, but:
What's the purpose of a seawall?

Hint: It's not to restrain a 90 ton load pulling away from the land on a few fixed anchor points. (They are designed for compression by waves)

As LittleWing77 says, it's doubtful that your insurer will cover the result of this inappropriate use.

[GordMay]

Greetings and welcome aboard the CF, 1fer.

[Sailmonkey]

Unless specifically designed as mooring points, any ties to a sea wall are done counter to the function of the seawall.

In other words, there is no recourse Unless the moorage contract specifically prohibits mooring lines attached to the seawall.

[1fer]

Originally Posted by LittleWing77

Sorry to say, 1fer, but I hope that 95-foot yacht's dock rental fees will be sufficient to cover your seawall reconstruction costs, because I'm speculating that your insurer won't...?

The yacht was docked just for about 3-4 weeks, so the answer is no...Insurance doesn't cover for inappropriate use

[Catalier]

You asked for advice, so here's mine...

Get a new seawall engineered and built with proper mooring points designed in.

[1fer]

Originally Posted by StuM

You don't say how the seawall was constructed, but:
What's the purpose of a seawall?

Hint: It's not to restrain a 90 ton load pulling away from the land on a few fixed anchor points. (They are designed for compression by waves)

As LittleWing77 says, it's doubtful that your insurer will cover the result of this inappropriate use.

Seawall was very old, probably 50-60 years. Concrete.

[1fer]

Originally Posted by Catalier

You asked for advice, so here's mine...

Get a new seawall engineered and built with proper mooring points designed in.

Exactly, at this point that is the solution, however I was asking from an engineering perspective, because I am not a professional in the field, if tying this yacht to the seawall itself could have been the cause of it falling apart. I believe the answer is likely yes from what I've gathered.

[1fer]

Originally Posted by GordMay

Greetings and welcome aboard the CF, 1fer.

Thank you!

[tkeithlu]

A concrete seawall looks nice and solid and strong. It looks like a good place to tie up just about anything. Trouble is, it's sitting on or imbedded in sand. This Florida. If it were rock, you wouldn't have needed it in the first place. You've basically used a block of concrete as an anchor, and the yacht dragged it. The bow (or stern) swung out, and the entire shore side of the hull bore against the current. That's a whooping big pry bar. Sorry it happened. Yeah, if mooring a big boat is your goal, get an engineer to specify pilings that will hold.

[1fer]

Originally Posted by tkeithlu

A concrete seawall looks nice and solid and strong. It looks like a good place to tie up just about anything. Trouble is, it's sitting on or imbedded in sand. This Florida. If it were rock, you wouldn't have needed it in the first place. You've basically used a block of concrete as an anchor, and the yacht dragged it. The bow (or stern) swung out, and the entire shore side of the hull bore against the current. That's a whooping big pry bar. Sorry it happened. Yeah, if mooring a big boat is your goal, get an engineer to specify pilings that will hold.

Thank you. I think that sounds accurate.

[mjscottinnc]

When I lived in FL sea wall construction and repair was controlled by the FL dept of natural resources, any additions, replacements, repairs had to be approved by the dept. it took my dad 12 years to get a design approved. The previous dozen designs were rejected. Things may be different now, that was back in the late 80s and 90s.

[BillKny]

I am kind of baffled by the question... are you trying to suggest it might be the fault of the yacht, and they should pay for repairs?

The seawall dock space was rented to a large yacht. If you rent me a place to tie up my boat it seem pretty clear that there is an implied warrantee that the place you are renting me is safe and suitable for securing my boat. Otherwise, WTF am I paying for?

Even if the CAUSE of the failure was the large yacht secured there (maybe), no possible way it is their FAULT.

Anybody who provides an answer to the engineering question without a physical inspection or at least pictures is just blowing smoke out their butt. There is NO WAY to know for the information available here.

Certainly there are thousands of places in Florida where superyachts are tied to seawalls and the seawall does NOT collapse. So the simple fact that the yacht was present is not the cause of the collapse.

The seawall was (obviously) not up to the job.
It was not an unreasonable job to ask it to do.
ergo, The seawall was defective.

[jimbunyard]

Originally Posted by 1fer

Hello cruisers,

I have a particular situation on a 100' seawall in Florida. The short story is that the seawall has completely collapsed into the waterway! The seawall was showing signs of deterioration and work was done to fix the visible issues. I contacted several seawall repair companies back in Sept-Oct 2020 and none of them provided information that would lead me to believe the seawall needed emergency action and all of these companies suggested similar scope of work/repair/price, so I thought everything checked out.

Later after the work was done, the dock was rented out to a big yacht (95' Ferretti) and the seawall started to show surface cracks on the cap not too long after that.

Looking at the pictures from the dock/security footage, I noticed the yacht was tied directly to the seawall itself so I am trying to determine if tying a boat this big/heavy to a seawall could potentially be a cause of an incident like this?

I was also able to gather some information regarding the weight of this yacht and it is in the 200,000 pound range.

The way I see this is tying a 200,000 pound yacht to a 50 year old seawall is like landing a helicopter in the roof of a an old house just because the roof is a flat surface doesn't mean its not going to brake apart.

Any advice/engineering perspective would be greatly appreciated.

Thank you

Since you give so little information about the 'seawall' itself, no real good information can be given in return, other than generalities.

Since the wall 'collapsed', after the ship tied up to it, it follows (as you know) that that had something to do with it's collapse.

A seawall' is typically constructed to protect against waves from one side, and to retain land on the other. Properly built, it should provide those functions within it's designed loads.

As noted previously, if pilings and mooring attachment points are not up to the load to which they're subjected, failure will result.

Without information, I'm guessing the top of the seawall collapsed into the canal (or whatever)?

Typically seawalls have deadmen, or anchor points, driven into the land side of the wall to which the wall is attached (generally) with steel rod or cable, to resist the force from the retained land. The land itself is used to provide resistance from the sea side.

If the wall is designed for large loads to be forced against the wall from the 'sea' side (say from ships), the connecting members will be solid and more numerous.

If the wall is over 50 years old, I'd guess the ultimate cause of the collapse was failure of the tiebacks. If the construction and failure is as assumed, and the companies you approached were aware of the age and the your intended usage, and you signed a proper contract, they might bear some sort of liability for failure to warn you of that possibility.

But I wouldn't bet on it...