Unique Way of tying off to pilings in slip to keep boat centered during storm surge

[Montanan]

Originally Posted by er9

I've never been to a marina in the hurricane zones of the US but dont the docks rise and fall with the tides? here in southern California, marina del rey they float and rise/fall 7-8 feet with our tide. we have pilings but they go through the docks and the dock rolls up and down the piling. is it not this way everywhere?

In non-fixed shoreline wharf marinas, yes floating docks that extend out into the waterways are the norm where there is tidal changes.

Of keen issue with hurricanes is the dramatic storm surge which causes rapid rises and lowering and extreme current and of course local waves.

If conditions get rough the floating docks can break free from their mooring piles and then all hell happens as the raft and associated boats shift and collide.

If the piles are not tall enough then the docks can ride off the top. Also the lever arm onto the piling increases as the docks ride up and that can lead to failure of the piling. It tends to be a rapid cascade of failures in a marina when a piling or dock fitting breaks loose as the freedom of movement on what part of the string of structures stresses the next fixture in line.

And of course if the boats can ride up onto the top of piling it will in turn become a hard and piercing object to the bottom of a hull.

[Shrew]

Originally Posted by er9

I've never been to a marina in the hurricane zones of the US but dont the docks rise and fall with the tides? here in southern California, marina del rey they float and rise/fall 7-8 feet with our tide. we have pilings but they go through the docks and the dock rolls up and down the piling. is it not this way everywhere?

There are Fixed Docks and Floating Docks. Storm surge is less of an issue with floating docks (unless the surge floats the docks above the tops of the pilings, which 'can' happen.

The OP description would apply to fixed docks, which can be tricky with storm surge. Leave the lines normal, and when the tide surges, there is too much slack and the boat 'pinballs' off of the pilings. Leave the too short, and when the low tide occurs, the boat is essentially 'hanging' from the lines tied to teh piles.

On fixed docks, once the docks go under water and swell starts rolling (if the docks are somewhat exposed) then you don't (don't want to) go out to tun the lines in the middle of a storm.

I sat through hurricane Irene in 2011 on fixed docks. I had sixteen docks lines and 10 fenders. The docks were 3 feet below the water with 3 foot breaking waves rolling through the marina. My neighbor's rub rail knocked the cap off of the top of the piling.

[Montanan]

Originally Posted by er9

I've never been to a marina in the hurricane zones of the US but dont the docks rise and fall with the tides? here in southern California, marina del rey they float and rise/fall 7-8 feet with our tide. we have pilings but they go through the docks and the dock rolls up and down the piling. is it not this way everywhere?

Marina del Rey has its natural hazards too.

Watch the effect of the tsunami in 2011 linked below, fortunately it arrived at not at high tide and was not that major in California.

https://www.youtube.com/watch?v=LoCSCj7kZ8s

[Dadrock33]

Mooring rings are nice and a good concept but I'd never use a wing nut on a fastener like that . . . . use a nylon "locking" net so the chance of it coming loose is down to nil!! Also, make sure you use at least a grade 8 bolt.

[Montanan]

Originally Posted by Dadrock33

Mooring rings are nice and a good concept but I'd never use a wing nut on a fastener like that . . . . use a nylon "locking" net so the chance of it coming loose is down to nil!! Also, make sure you use at least a grade 8 bolt.

Good point. I agree that one should not use a wing nut to fasten if the fastening is not supposed to easily unfasten.

Not sure which ring you noticed a wing nut on in its fabrication, but yea, if it has such it should be replaced.

As to the grade of fasteners, all too often I have seen failures in marine applications, especially on docks, in particular as to the assembly of the dock or to the hardpoint attached to the docks. Many a cleat has sheared due to inadequate fastener strength or corrosion. or by not being through bolted but rather lag screwed. Many times people just purchase common bolts from te local hardware store which have weak strength and workmanship.

My suggestion of a foam filled tire makes for a very strong and durable float and is inexpensive, but definitely is not classy looking; just use Michelin tires to go upscale. 50,000 miles, or 50,000 tidal changes. .

The rings that I have seen, albeit of which I have only seen a limited number of types appeared to be of fairly robust construction. Of issue is the tonnage of boats that one is going to attach to and their yield strength during storm loading.

By way of example the image below used standard nylock nuts in its bolt fastenings but I would worry about the robustness of the polymer ring itself if I had a 30,000 + boats tugging harshly on it. Whereas a steel belted radial thick sidewalled, truck tire wrapped with a dock line isn't going to readily tear apart and will give a little stretch.

[thinwater]

Floating docks vary regionally. For example, they are rare in the Chesapeake Bay. The reason is that in much of the bay, the tide is quite limited, no more than 2 feet. However, when a hurricane or tropical storm tracks up the Bay, I seen storm surge of 8-11 feet.


Most of the slips are sized so that this can be accommodated. In fact 3-to 5-foot variations due to strong north winds and winter storms are common, so most folks tie their boats safely for large swings. But once in a while someone doesn't get it, with disastrous results. A small power boat was pulled under in the slip next to mine ~ 5 years ago. He didn't cross his lines.

[ranger58sb]

Originally Posted by Montanan

[B][SIZE="3"]An alternative is to provide a floating ring around the pile that rises and falls with the water level, and to which a boat mooring line can be attached.

I tried one of these:

Pile Ring – Pile Ring a revolutionary all-tide all-weather mooring device

Worked for changing tides well enough, but it would not allow the correct angle on the line to keep us from bouncing off the piles on the other side of the boat. See pic attached to post #9.

-Chris

[Montanan]

Originally Posted by ranger42c

I tried one of these:

Pile Ring – Pile Ring a revolutionary all-tide all-weather mooring device

Worked for changing tides well enough, but it would not allow the correct angle on the line to keep us from bouncing off the piles on the other side of the boat. See pic attached to post #9.

-Chris

Curious. Chris, might you please expound on your experience and the mode of apparent failure, as I am a bit confused why there would be a difference as to inhibiting the vessels travel towards piles located on the opposite side of the vessel due to the line being positioned at water level instead of say, some fixed position higher up the pile.

The picture attached to my post # nine shows a single pile ring float shared between two adjoining slips which are intended to keep each of the boats from shifting away from each other, e.g., to avoid making contact with the finger pier. Those two pile lines [one from the bow of each adjoining vessel] and that piling are not intended to inhibit the adjoining moored vessels from traveling towards each other. When the adjoining boats float towards each other, their lines that share the piling are being pushed not pulled [pushing on a string] . The adjoining boats are restrained from making contact by the lines attached elsewhere, either to finger piers or a piling on the opposite side of the piling that was being shared, which lines tighten when their slack is taken up.

In my experiences where the slip is a tad short the boats attached to pilings can bash hard against such pilings. When the slip is longer than the vessels moored in them then the pilings are not of danger of being contacted.


Edit added: Upon deeper thought, perhaps you are indicating that if the slip is narrow such that the boat might drift sideways in its slip it could contact the piling on the opposite side of the piling with a floating ring, which is to say, forming a hypotenuse angle with the mooring line will cause to much lateral movement. If that is the situation then the mooring line to the piling needs to be made short so as to not allow the boat to slide sideways and one would need a floating ring that has a raised attachment point, say near deck level so that the mooring line remains a short horizontal distance from the vessel's connection point, e.g. cleat. That would be a cleaver bit of kit and a modest modification from the water level floating ring devices. There would be a floating ring and risers up to a second pile ring which second pile ring does not need to be a floating ring but rather a tie point ring. The floating ring at the water level would need to provide for adequate floatation to hold the vertical risers and the upper tie point mooring ring, so things would need to be comparatively oversized to handle a greater weight displacement. And perhaps the risers could be made to be adjustable to accommodate various freeboard levels of vessels.

Please advise. Thank you.

[thinwater]

A few thoughts:
* I've moored through 2 hurricanes that over topped the piling in my marina (surge more than 7 feet). No vessels were damaged. There are no floating docks and the lines were tied high on the pilings (at normal high tide the lines are still actually angling up). So no, over topping the pilings does not have to be a death sentence. It's not really a concern to us.
* My slip is pretty tight (about 16 inches on each side, perhaps 2 feet fore and aft). However, I do cross the lines and I run fore and aft springs (4) on both sides. This accurately controls the motion of the boat.


I like the idea of free floating mooring attachments. Variations have existed for a century or more, used in areas with considerable tide (floating dock but boats tied to dolphins). But it seems like the whole marina needs to be on the same system.

[Montanan]

Originally Posted by thinwater

A few thoughts:
* I've moored through 2 hurricanes that over topped the piling in my marina (surge more than 7 feet). No vessels were damaged. There are no floating docks and the lines were tied high on the pilings (at normal high tide the lines are still actually angling up). So no, over topping the pilings does not have to be a death sentence. It's not really a concern to us.
* My slip is pretty tight (about 16 inches on each side, perhaps 2 feet fore and aft). However, I do cross the lines and I run fore and aft springs (4) on both sides. This accurately controls the motion of the boat.


I like the idea of free floating mooring attachments. Variations have existed for a century or more, used in areas with considerable tide (floating dock but boats tied to dolphins). But it seems like the whole marina needs to be on the same system.

Thinwater that is a thin slip, or rather your cat fills it well. Having a cat certainly aids in dealing with such a situation as crossing the lines is rather easy, one leading from each hull, ditto for pontoon boats. Do you have hardpoints at the end of each hull so that the cross lines run clear of the hull, or are they in the inner side of each aft hull?

A monohull is challenged as to not being as well suited to utilizing a cross dock line for and aft.

If the storm surge was to top the pilings a floating ring would be rather catastrophic as it too would slip off, unless there was some kind of retention device to limit from not going over the top, but just rising to the top.

Glad to hear your boat survived such adverse conditions, must have been quite the worry.

How well did the other boats handle the situation? Was there any specific failure point common on any damaged boats?

[ranger58sb]

Originally Posted by Montanan

Curious. Chris, might you please expound on your experience and the mode of apparent failure, as I am a bit confused why there would be a difference as to inhibiting the vessels travel towards piles located on the opposite side of the vessel due to the line being positioned at water level instead of say, some fixed position higher up the pile.

In the pic.... the length of the line from pile ring to blue boat (because of the angle) won't keep the blue boat from bouncing off the pile on it's port side.... and the length of the line from pile ring to white boat (ditto) won't keep the white boat from bounding off the pile on its starboard side.

Maybe also a function of slip width versus boat beam, but... nothing abnormal about our dock, so I suspect it's a typical issue.

Yes, our bow lines run almost horizontal, so they're maybe 2/3rds the length of the bow lines when they were run from the pile ring.

I thought about crossing bow lines, but the appropriate path would be under our pulpit and back up/around on the other side... and I haven't been able to figure out a way to eliminate chafe. And I'm not sure the length would be appropriate even after all that.

-Chris

[wsmurdoch]

These were installed in our part of our marina.

From the website Pile Protection | Sag Harbor NY

When Florence came to New Bern the unprecedented 12.5 ft surge raised the devices to the tops of the pilings and the boat dock lines pulled them over the tops of the pilings. The result was catastrophic. The wind blew the freed but still tied together boats over the fixed docks where they were stranded by the falling water.

My boat is the single blue hull boat visible on the far side of the dock. She was nearly undamaged, but I had run additional lines to the docks beside and behind me, and one slip beside me was unoccupied.

Bill

[thinwater]

Originally Posted by Montanan

Thinwater that is a thin slip, or rather your cat fills it well. Having a cat certainly aids in dealing with such a situation as crossing the lines is rather easy, one leading from each hull, ditto for pontoon boats. Do you have hardpoints at the end of each hull so that the cross lines run clear of the hull, or are they in the inner side of each aft hull?

A monohull is challenged as to not being as well suited to utilizing a cross dock line for and aft.

If the storm surge was to top the pilings a floating ring would be rather catastrophic as it too would slip off, unless there was some kind of retention device to limit from not going over the top, but just rising to the top.

Glad to hear your boat survived such adverse conditions, must have been quite the worry.

How well did the other boats handle the situation? Was there any specific failure point common on any damaged boats?

As I said, no boats were damaged, and most were not cats. But ALL crossed the stern lines. Also, lines were attached relatively high on the pilings, such that the lengths at peak surge were not much different from normal.


The forward cleats and fairleads one cats are usually rigged for this, since they use a bridle to anchor. Not always.


The stern cleats can be used if some manner of deflector or hard point is added. Why this is not factory is beyond comprehension IMO.


(The line is coated with Yale Maxijacket, which arrests chafe. The carabiner is just a deflector and does not carry much load.)

[clayzone]

Doesn't look like the tide rings will work if you are tied up sideways to a fixed dock. Correct me if I am wrong because they look like the easiest solution for dealing with tides.

[BobMc]

Why not just tie off a lingth of line at the top and low point on the piling with it run through a single heavy block which would ride up and down the line? Seems a lot simpler; not sure of an advantage to using two blocks, one at the top and lower water level.

You wrote:
Tie a block using dockline and clove hitch to the top one foot of each piling in your slip.
Repeat the process at the lowest point at water level to the bottom of each piling.
Now, run a dockline from your starboard bow deck cleat to the top block on the piling and run it through, then down through the block on the same piling at water level, then back up to your bow cleat to be tied off. This forms a triangle.