How Some Marinas are Dealing with the Problems of Storm Surge, Hauling Boats, Exposed Locations . . . What About Hurricane Plans?

When hurricane Fran came blasting across North Carolina’s Outer Banks in October 1996 and up Masonboro Sound, Susie Brigman said she’d never seen anything like it. In her 26 years at Masonboro Boatyard, Susie had seen several hurricanes, but this category three storm was something altogether different.

Before the storm, she and the other marina personnel contacted owners, moved boats, added lines and chafe gear, put most of the boats in the boatel onto trailers so owners could haul them away, and secured marina property. The marina was ready, or so she thought. Fran blew all night and as morning dawned she got her first glimpse at what the storm had done: the harbor was empty. Boats, most still tied to their floating docks, had floated away. A few had sunk, but most were scattered ashore, piled awkwardly on top of each other in clumps, leaving only a few scattered pilings to indicate what had once been a marina.

Evaluating Your Marina: How Safe are the Docks?

Three years after Fran, Masonboro Boatyard is a much different marina, although the difference isn’t readily apparent. The docks were rebuilt and the buildings repaired. The boats are back. On the surface it looks the same, but Susie Brigman didn’t make the same mistake twice. When the floating docks were replaced, new pilings were driven far into the bottom that tower 18’ above the water. The additional height looks slightly ungainly, but the docks are far less likely to be lifted over the pilings by a storm’s deadly surge. Masonboro Boatyard is better prepared.

If a category one storm is expected, the likely surge (according to the Saffir-Simpson scale) is only 4’ - 5’; a category two surge is 6’ - 8’; a category three surge is 9’ - 12; a category four surge is 13’ - 18’; and a category five surge is above 18’.

Low lying areas and seawalls are also vulnerable to storm surge. One facility that was especially hard hit by a hurricane was the Houston Yacht Club, which lost 141 of its member’s boats in hurricane Alicia. For many years, the boats at the Houston Yacht Club had been protected by an 11’ high x 20’ wide earth and cement seawall. Then in 1983 the club expanded the number of slips by constructing a wood seawall further out from the older seawall.

When hurricane Alicia came ashore with 135 mph winds, Galveston Bay quickly rose over the new outer seawall and, one by one, the windward boats nearest he submerged seawall broke their lines in the heavy seas and smashed against the boats to leeward. Only a few of the boats behind the taller inner seawall came loose.

Evaluating Your Marina: Storage Ashore

A study by MIT after hurricane Gloria found that boats stored ashore were far less likely to have been wrecked than boats stored in the water. The problem at many marinas is that hauling and blocking boats ashore takes time, which is in short supply once a hurricane warning is posted. Another problem is storm surge and the height of the marina storage facility.

Shortly before hurricane Fran came ashore, John Parker, a BOAT/U.S. Member in Wilmington, North Carolina, was assured by his marina manager that his sailboat would be hauled out and blocked ashore. John stripped his boat and then moved it over to the bulkhead next to the travelift. Since the boat was going to be hauled, he didn’t add extra lines and chafe gear. In the ensuing chaos that proceeded the last few hours before the storm, John’s boat was overlooked. When storm came ashore, the boat was carried up and over the seawall and destroyed.

The time problem can be solved, at least partially, by careful planning. One of the first things Philip Hale did after Bob battered his marina, Martha’s Vineyard Shipyard on Martha’s Vineyard, was put together a list of emergency employees, including many former employees and some local boat owners who are familiar with the boats and boatyard. This emergency staff is organized into teams, each having a specific assignment and leader, who can be called upon to join the regular staff whenever a large storm is approaching. Hale’s largest team is assigned to haul, block, and prepare the boats; there are other teams to secure the buildings and grounds.

At another New England marina, Burr Brothers in Marion, Massachusetts, was also hit hard by Bob as well as an earlier hurricane, Gloria in 1985. Toby Burr now keeps a list of boat owners who have agreed to have their boats hauled by the marina whenever a hurricane threatens. The decision to haul boats is left to marina personnel, and Toby says it puts an extra burden on them to decide at what point a storm might pose a threat. The responsibility is more than offset, however, by the additional time it gives them to evacuate boats.

While almost all of the boats hauled by Burr Brothers when the marina was hit by Hurricane Gloria escaped with relatively little damage, boats that were stored ashore during Hurricane Bob were not so fortunate. Unlike Gloria, which came ashore at low tide, Bob had a much greater surge and many of the boats stored in the yard got knocked off their cradles by the rising water. To prevent a recurrence of the damage done by the surge, Burr Brothers has arranged to receive NOAA charts that predict when and where the surge is likely to be highest. If the surge predicted could be a threat to boats stored ashore, Burr Brothers has a contingency plan to unstep masts so that boats can be moved further inland to higher ground.

Other low-lying marinas have opted to recommend that boat owners seek higher ground elsewhere. Ashley Marina in South Carolina, doesn’t have the facilities to haul boats, and even if it did, the grounds are too close to sea level to offer even minimal protection from tidal surge. Rhodes recommends boat owners take boats to nearby Ross Marina, which has a travellift and a storage areas that is a much safer 15’ above sea level. David Browder at Ross acknowledges that many of his regular customers have already made arrangements to have their boats hauled and stored at his yard whenever a storm threatens.

Boats at Fixed Docks

If you plan to leave your boat at a floating dock, it’s critical that you measure the height of the pilings--will they remain above the predicted storm surge? A fixed dock presents an even greater problem. With a fixed dock, a boat must have sufficient scope to allow for storm surge, Lines that are too short will be stressed and broken by the surge. On the other hand, simply increasing scope to existing pilings typically results in too much slack--the boat will be slammed against the pilings--when the storm first comes ashore.

The remedy is to secure longer lines to more distant pilings or even trees. The larger the slip, the better. This allows the boat to rise without greatly increasing the risk that it will be destroyed against pilings. If lines can’t be extended to allow for surge, or if a slip is only marginally larger than the boat, the only safe alternative is to move the boat to a hurricane hole or have it hauled and stored ashore.

Evaluating Your Marina: Hurricane Plans

After boats in its outer harbor were devastated by Hurricane Alicia, the Houston Yacht Club responded by devising a comprehensive Hurricane Plan, which includes evacuating ALL of the boats in the outer harbor whenever a hurricane warning is posted. This massive job requires an enormous commitment by all of the club’s members, each of whom is required to submit a hurricane plan with their harbor rental agreement.

Owners are required to make arrangements to move boats to hurricane holes or alternative dock sites further inland. Each plan must include details on where the boat will be kept, what equipment is available, and the name of a “boat buddy“ who will take care of the boat if the member is sick or out of town. Plans are submitted to the club’s Hurricane Committee for approval.

Plans must conform to the overall guidelines set by the club. For example, boats in the outer harbor have to be evacuated, and arrangements must be made to move them to hurricane holes and alternative dock sites further inland. In the event of a storm, boat owners report to one of the 14 dock captains, who coordinate the preparation efforts at each of the club’s docks.

While the Houston Yacht Club Plan has been used as a model by many other yacht clubs and marinas, it is important to note that there is no such thing as a generic hurricane plan--a plan that will work for everyone. Each facility is different and arriving at a viable plan takes time. Should a hurricane come ashore, an extraordinary amount of work will have to be done in only a few hours. Planning should begin months in advance.

Securing a Boat Before a Hurricane:

In Florida, It’s the Law!

One type of hurricane plan devised by some marina owners in Florida has been to kick boats out whenever a hurricane warning is posted. This “plan” was good for marina docks and buildings but not so good for the displaced boats. And it was definitely not good for the boat owners, who would have to risk their lives moving boats in the face of rising winds and seas.

After hurricane Andrew, a law was passed in Florida that prohibited marina owners from ordering boats to leave the marina after a hurricane warning is posted. Marina owners responded by altering language in slip contracts to say that boat owners were liable for damage to the marinas if boats left in their slips during hurricanes. “Your boat can stay, but . . . “

Last spring, a Florida appellate court failed to support a marina owner’s damage claim against several boat owners who left their boats at his marina during hurricane Opal. The judge said, however, that a marina can hold a boat owner liable if his or her boat isn’t secured properly.

“Secured properly” isn’t defined, so it behooves a boat owner to take extra steps--the more the better--to secure a boat when a hurricane is approaching. This means adding extra lines, chafe protection, and stripping the boat. How Some Marinas are Dealing with the Problems of Storm Surge, Hauling Boats, Exposed Locations . . . What About Hurricane Plans?

When hurricane Fran came blasting across North Carolina’s Outer Banks in October 1996 and up Masonboro Sound, Susie Brigman said she’d never seen anything like it. In her 26 years at Masonboro Boatyard, Susie had seen several hurricanes, but this category three storm was something altogether different.

Before the storm, she and the other marina personnel contacted owners, moved boats, added lines and chafe gear, put most of the boats in the boatel onto trailers so owners could haul them away, and secured marina property. The marina was ready, or so she thought. Fran blew all night and as morning dawned she got her first glimpse at what the storm had done: the harbor was empty. Boats, most still tied to their floating docks, had floated away. A few had sunk, but most were scattered ashore, piled awkwardly on top of each other in clumps, leaving only a few scattered pilings to indicate what had once been a marina.

Why Do Some Nylon Anchor Lines Hold and Others Break in a Storm? (And Why the Anchor Line You’ve Been Using for Years is Likely to Fail)

As sometimes happens in early spring, a line of dark clouds suddenly appeared on the horizon and Dan Arsenault got caught in an especially violent April thunderstorm. He had been bringing his 37’ sailboat from its winter storage yard to its summer home near Saginaw Bay, Michigan when the wind built to near hurricane force (74 knots) and seas grew to nine feet. It was cold, bitterly cold.

Dan’s boat had been passing through a narrow channel and was bounced off of the bottom several times, damaging the rudder. After a brief attempt to work his way into the marina, Dan crawled up to the bow, set the anchor and went below to wait for the wind to subside. Moments later, amid the horrific noise of the storm, he heard a loud “explosion.” The anchor line had parted.

In less trying conditions, nylon’s ability to stretch makes it an almost perfect choice for an anchor line. The stretch absorbs shock, which means less strain on the anchor, less jerking, and a more comfortable night’s sleep. One of the most frequent complaints from BoatUS Hurricane Cat Team members, however, is that the same nylon rodes that are fine for everyday use have proven to be woefully inadequate in a violent storm. In Florida last year, hundreds of boats were driven ashore because their nylon anchor rodes—usually more than one—had parted.

When a boat winds up on the beach after a storm, it’s easy to look at the frayed remains of the anchor line and announce that it had chafed. The solution has typically been to recommend more and better chafe protection. The fact is that the ”chafed” line could have been broken—exploded—under the tremendous load because it lacked strength, it could have failed suddenly because it lacked elasticity, it could have failed internally—melted—by the tremendous heat, and it could have failed for a combination of reasons.

While there are plenty of examples of nylon anchor lines that failed, there have been at least as many examples of anchor lines that survived, despite being tested for many hours by the same high winds and seas. Seaworthy talked to representatives from the major rope manufacturers as well as members of the BoatUS Hurricane Catastrophe team to find out why some anchor lines—and boats—are more likely than others to be counted among a storm’s survivors.

Five Critical Factors That Predict How Rope Will Fare in a Storm

1. Breaking strength is determined by wrapping new rope around two large diameter capstans and slowly tensioning the line until it breaks.

All things being equal, a braid-on braid line will have the most breaking strength followed by plait and then three strand. You might think that breaking strength (tensile strength) would be the ultimate criteria for selecting an anchor line. After all, the line that’s the strongest would have the best chances of surviving the tremendous forces in a hurricane. Alas, the forces on a rope in a hurricane are not applied slowly on large diameter drums; it takes more than breaking strength for a rope to survive something as violent as a hurricane. Breaking strength is only one of six factors.

2. Stretch. While breaking strength is clearly important, stretch is also essential to act as a shock absorber to absorb the tremendous amounts of energy. There are two ways that a rope absorbs energy: 1. The material itself stretches and 2. The weave of the material can expand and contract mechanically. Before the fiber itself stretches, the lay of the rope untwists and absorbs energy.

Nylon stretches more than polyester and, all things being equal, a three-strand twist line will stretch more (and absorb more energy) than a braid-on-braid line. A plaited line (similar to three strand but softer and with a square profile) will stretch more than either three-strand or braid-on-braid.

Without something that stretches to act as a shock absorber, the intense gusts and surging waves are much more likely to yank an anchor out of the bottom. A line that stretches also helps to prevent a boat from “sailing” back and forth on the rode, which puts additional strain on the anchor and rode. The greater its ability to absorb the sudden and violent stresses, the less likely an anchor line will fail.

3. Chafe and Cleat Location. All of this stretching back and forth across a chock has the potential to chafe the line, especially if it is secured to a cleat that is a foot or two away from the chock; the increased distance gives it more room to be stretched. If the chock isn’t baby-butt smooth, all of this rubbing under pressure will quickly lead to external chafe. Note, however, that the potential for external chafe is only one of several ways a line can fail at a chock. When the line is bent sharply down to the water, only about half the ropes fibers are taking the load. Because of compression, the remainder of the fibers will be ineffective.

Stretching and rubbing at a sharp angle also creates heat, a lot of heat. Nylon line starts to deteriorate at 300° F and at 350° it will have lost half its strength. There have been many instances at a chock where lines have melted and failed internally.

4. Age. The nylon fibers that are woven together to make a rope are thinner than a human hair. One thing you don’t want in contact with a nylon rode is dirt, which, over time, abrades fibers and weakens the line. Salt crystals, while not as destructive as dirt, also abrade fibers.

Unfortunately, dirt and salt are found in abundance on the sea bottom, which means that an older line, even one that is healthy looking and supple, may be significantly weaker than its spanking-new counterpart. Fibers are also weakened by sunlight and exposure to certain chemicals, including acids and alkalis .

There are other ways that nylon rope can be affected by age. Repeatedly expanding and contracting weakens the fibers; the more times the line has been used and heavily stressed, the more likely it has been weakened. Agai, damage and loss of strength may have occurred without any discernable signs of weakness.

Some types of damage are apparent. As they get older, nylon lines become stiff as they shrink and fibers lose lubricant. Better quality nylon line is pre-shrunk but it’s not possible to eliminate all shrinkage; some is inevitable. The lubricant, also found on better nylon line, minimizes shrinkage by keeping water from penetrating the fibers. Lubricant has the considerable added benefit of reducing yarn-on yarn friction, which helps to reduce heat. As noted earlier, excessive heat can severely weaken nylon line.

Two obvious indications that the line is shot are stiffness and, when it’s under load, “squeaking.” But what about a well-used nylon line that is still supple and looks healthy? With industrial applications, rope is often retired at pre-determined intervals, typically after two-three years of everyday use, to prevent catastrophic failures. Nobody knows how long an anchor line should be depended on, but a line has been used hard and often will likely be significantly weaker than a new line.

5. Line quality. As noted, better quality line is pre-shrunk with lubricant added to the fibers. The way a line is woven is also important. Three-strand twist should always be built with a medium lay construction. The latter has more twist (“mechanical twist”) and will absorb energy more readily than rope made with soft-lay construction. While easier and cheaper to manufacture, soft-lay rope is much more prone to failure. If it’s easy to separate the strands, the line is probably soft lay. Braid-on-braid rope can also be made with a soft-lay construction, but it “herniates” readily and is far less common.

Some Possible Solutions to the Problem of Failed Rodes

The question for boat owners is what type of line or lines will stand the best chance of surviving a hurricane?

First, the obvious: The boat’s chances of surviving a storm can be improved significantly by using more and larger lines. All things being equal, a ¾” line will outlast a ½” line and two ¾” lines will outlast a single ¾”line. The size of the line will likely be determined by the size of the cleat(s).

Another obvious choice: A rode (and storm anchor) that is used purely for anchoring the boat in a storm should be made up before the start of hurricane season. The boat’s everyday working rode should not be relied on; it probably isn’t big enough and, if it has been in use routinely much of its resiliency and breaking strength will have been compromised.

A Rode is a Rode is a Rode . . .

Anchoring Outside the Box

Using larger and healthier lines is a good start, but there are more choices yet to be made. For starters, what type of line—braid-on-braid, three strand, or plait—will work best? After Dan Arsenault’s harrowing experience (the boat survived, albeit with a bent rudder shaft and two badly shaken crew) he replaced his failed nylon braid-on-braid rode with nylon three-strand. The reason, he said, was that the three-strand line has greater elasticity—more stretch—to absorb the violent loads. The bow of his boat had been thrown high into the air by waves in the open water and the lack of elasticity in his line (and perhaps its age) led to the failure. Would three strand or plait have survived? It’s hard to say.

The obvious question is how much of a trade off in breaking strength do you want to make for additional energy absorption? Once again, the answer is that nobody knows. It could be (with no studies to back it up) that using three strand nylon or plait to maximize energy absorption is more critical in an exposed anchorage where the bow will be thrown high into the air by large waves. Loads are applied suddenly and violently and the line will have to absorb a tremendous amount of energy if it’s got any chance of surviving. In a sheltered harbor, waves (and sudden shock loads) should be significantly reduced. Wind would then become the primary force acting on the boat, and opting for increased breaking strength (braid-on-braid or even polyester) might be a better choice.

A few words about polyester are in order. One of the rope manufacturer’s experts, who also happens to own a boat, said he would consider using a combination three-strand polyester rode with a nylon rode in a hurricane. The two could be looped eye-to-eye (see diagram) to avoid having a knot in the line. (Knots weaken a line by as much as 50%.) Polyester would be used from the cleat through the chock, where the rode is most likely to be stressed, with the remainder of the rode being nylon (see diagram).

It’s an interesting idea that was first introduced by Norman Doelling, who was then the Assistant Director of the MIT Sea Grant Program. Polyester is much tougher and far more resistant to chafe, both internal and external. Nylon is more comfortable in the under 25% range of its breaking strength, but beyond that it begins to quickly fatigue. Polyester has the capability of going to 50% – 60% of its breaking strength without fatiguing, at least not quickly. Even when wet, polyester line retains full strength (nylon loses strength, although water is necessary to cool the stressed fibers).

There are other alternatives to conventional nylon anchor lines. Yale Cordage makes a braid-on-braid mooring pennant that has a nylon core for stretch and shock absorption and a polyester outer core to resist chafe. The outer core is woven to produce stretch (mechanical) that is comparable to stretch in the nylon core. The line is sold in shorter lengths with eyes for use as mooring pennants. Yale sells the line in spools for other markets but it can be special ordered by a marine chandler.

Another choice mentioned frequently by manufacturers’ experts is plait. The main selling point of plait has been that it is soft and pliable, takes up less space in an anchor locker than conventional rodes, and can be twisted without hockling. But plaited rope is also more elastic and has more breaking strength than three strand (although it is not as strong as braid-on-braid). It is also worth noting, that plait is easily spliced.

Chafe Protection

Cleat location is a significant weak spot that is often overlooked when a boat is prepared for a hurricane. A cleat that is located on the rail is ideal because it avoids heat build up, loss of strength, and chafe that is caused by stretching rope across the chock at a sharp angle down to the water. The line won’t be compressed as tightly, it won’t generate as much heat, and it will be far more likely to weather the storm intact.

On boats where the cleat is located back from a chock, it may be possible to move the cleat. Note, however, that the cleat must be installed properly or the whole effort will have been for naught. Bolts and not screws should be used to secure the cleat and it should be backed with a wood or metal backing plate to distribute the load (washers are not adequate).

If the cleat can’t be moved, the choice of chafe protection will be critical. Various types of hoses—PVC, garden hoses, and even fire hose—have the potential to reduce compression at the chock as well as protect the line against external chafe, which is good. But these types of hose will allow heat to build up and prevent cooling water from reaching the fibers. The best way to reduce the chances of the line failing at the chock is to use something like polyester chafe protectors, which let heat out and allows water in.

Don’t forget that rodes can be chafed underwater as well. Chain should be used between the anchor and anchor line to prevent chafe on the sea bottom. If a lot of chain is used, at least a third of the rode should be nylon line to absorb shock. Make sure the thimble splice is snug; loose or broken thimbles have been the downfall of more than one anchor line in a storm.

Comparable Average Breaking Strengths For Different Rope Sizes and Types*

* Source: Yale Cordage

Seaworthy’s “Hurricane Warning: A Guide to Protecting Boats and Marinas for Hurricanes” notes that the probability of damage can be reduced considerably by “choosing the most storm-worthy location possible” and making a plan before a hurricane warning is posted. (Sound advice, so far.) The Guide goes on to note that a boat in the water should only be secured in a well-protected marina: “A seawall or sandy spit that normally protects a harbor may not offer any protection in a hurricane.”

May not offer any protection? After spending a considerable amount of time driving to various marinas after Hurricane Isabel, Seaworthy can now safely say that the last sentence is an understatement—a HUGE understatement. Of the thousands of words that have appeared in Seaworthy concerning hurricane preparation, “choosing the most storm-worthy location possible” are the most critical. Does having a boat in a well-protected harbor guarantee safety? Of course not. But the choice of locations is the single most important decision a boat owner has to make before a storm. It dwarfs all others.

In this issue, Seaworthy looks at three marinas that were in Isabel’s path. All are well run marinas; well respected and popular with local boaters. All three have management that clearly had given considerable thought to hurricane preparation. All three, thanks to their staffs and boat owners, had been carefully prepared for Isabel. That’s where the similarity ends, however. By the end of the storm, the outcomes at the three marinas were completely different. And the difference was their location.

Before the Storm: Preparations

Three days before Hurricane Isabel was expected to come ashore, Hartge personnel began calling every one of the 297 boat owners at the yard with a brief reminder: Preparing your boat is your responsibility. Details on hurricane prep, owners were told, had been posted at the yard’s website.

Hartge’s service manager, Luke Frey, said he had been pleasantly surprised at both the size and intensity of the response; later that afternoon a steady stream of cars began pulling into the yard as owners set to work removing biminis, dodgers, dinghies and sails, and adding extra lines and chafe protection to their boats. Several owners moved their boats to nearby hurricane holes—Mill Creek, Whitehall Bay , and the Severn River . A few others had their boats hauled and blocked ashore. Meanwhile, the normal work routine at the 139-year-old boatyard was suspended as Hartge’s 35 employees went to work preparing the docks, buildings and grounds. The frenetic activity continued until Thursday afternoon, when most of the employees headed home, leaving only a handful of volunteers at the yard to wait for the rapidly approaching storm.

Plans for Isabel began on Monday when Isabel was still off the coast of Georgia . Steuart Chaney, Herrington’s president, started making plans to prepare the marina with Alex Persons, Herrington’s harbormaster. Chaney described the plans the two eventually made as “elaborate.” First, all 1,300 boat owners at Herrington North and South were called, and most came to the marina to prepare their boats. Marina staff walked the docks over and over, noting potential problems. Some boat owners were then given a second call. Dozens of boats—a total of 165 in three days—were hauled and blocked ashore. Chaney said anything on the grounds that “could float or fly” was secured by marina personnel. Windows on buildings were covered with plywood. Just as the storm started coming ashore, danger signs were placed at each dock and the power was cut off.

Further south on the James River , personnel at Jordan Point Yacht Haven had also been calling boat owners. Their message was different: Boats either had to be moved to a hurricane hole or they were going to be hauled and blocked ashore. Boats would not be allowed to remain in their slips during Isabel. The reason, according to Mike Winn, Jordan Point ’s owner, was that the docks were too vulnerable; several boats had sunk at their slips when Hurricane Fran skirted the area in 1996 and Isabel promised to be a much bigger storm. Winn said he wasn’t taking any chances.

Several of the owners opted to take their boats to a hurricane hole—a large, well-protected gravel pit further up the James. The remainder were hauled and, by late Wednesday, 80 boats had been blocked ashore in two neat rows facing the water. Slips were now empty. The buildings and grounds had been secured. There was nothing more to do but go home and wait.

Friday morning dawned bright and sunny with nary a hint—as long as you were looking skyward—of what had taken place the night before. The ground, however, was a different story; it was carpeted with leaves, hundreds of branches, debris, and fallen trees. Power lines were down. Homes were damaged. And along the shores of the Chesapeake and its many tributaries, water was just beginning to recede from backyards, marina parking lots, and docks. A boat owner who arrived at Hartge early that morning said he saw a kayak being paddled along a dock that was still well below the surface of the water.

Even though Hartge sits on relatively high ground, the water had flooded several of the buildings, destroying the paint inventory in the stock room and the welding machine at the yard’s rigging shop. As for the boats, a few had been scratched by handholds that jut out from pilings on finger piers, but the damage was minor. Most of the marina’s boats were completely untouched. Some of the credit has to go to Hartge volunteers who stayed up all night, first loosening the lines on boats as they rose and then taking up the slack as the surge receded.

Ultimately, though, the credit for Hartge’s success has to go to the marina’s sheltered location. The effort by Hartge staff to protect boats, however commendable, would have been impossible at Herrington North or Jordan Point . A seawall that protected the boats at Herrington was overcome by the surge, exposing boats at the marina’s A, B, C, and D docks to breaking waves. Large sections of the docks had been destroyed and some of the boats—a total of eight—were sunk. Many more were damaged.

The worst devastation occurred at Jordan Point . During the night, Isabel’s eight-foot surge and six-foot breaking waves destroyed the vacant docks and then rose over the banks, lifting all 80 boats off their jack stands and floating them against a hill behind the parking lot. The boats were then bashed against each other for several hours, leaving them in mangled clumps when the surge finally receded. All were damaged and many were a total loss. A few were broken into pieces and strewn about the parking lot.

As you might expect, Hartge’s Frey was the only one who wasn’t talking about major changes, aside from moving equipment to higher ground, after Isabel. At Herrington North, Chaney has begun rebuilding a total of 250 slips with completion scheduled sometime later this summer. A taller seawall will also be replacing the one that was overcome in Isabel. A second seawall, one that will protect the harbor from the southeast, may also be built. Chaney said that the second seawall had been discussed before Isabel and he’s confident that the project has the impetus to finally be approved. With new seawalls, boats would be much better protected. If the second seawall isn’t built, the only alternative will be to move all of the boats whenever the area is threatened by a hurricane.

Jordan Point is also rebuilding; the fixed docks are being replaced with floating docks and taller pilings. There will also be a breakwater at the perimeter, although it won’t be sufficiently tall to protect the boats in a significant storm surge. Should another Isabel be forecast, the boats likely would have to be moved, although to where or how has yet to be worked out. Mike Winn says he’s just thankful to be rebuilding.

The message to boat owners is clear: “A seawall or sandy spit that normally protects a harbor may not offer any protection in a hurricane” . . . a few small words that somehow don’t convey the message.

The boats at this marina on Miller Island , Maryland had all been moved ashore to “high ground.” Unfortunately, high ground on Miller Island isn’t very high. The surge came over the outer breakwater and breaking waves flooded the surrounding property, wreaking havoc with boats and houses. At one point, the entire island was underwater.

Perhaps the most famous story of marina destruction, occurred at the Houston Yacht Club during Hurricane Alicia in 1983. A storm surge, pushed by 135-mph winds, combined with normal high tides to overcome the low-lying outer seawall. The protected harbor then became an open bay and all of the boats—a total of 141 boats—in the harbor either sank or were carried ashore.

As a result of the storm, the Houston Yacht Club put together a remarkably detailed (75 pages) hurricane preparedness plan that must be adhered to by all members. The plan calls for every boat in the outer harbor to be moved or hauled out ashore.

The wind blew across the long, unprotected fetch of the James River (that can be seen under the shed) destroying the docks and sheds.

Even though all of the boats were damaged, the decision to haul and block them ashore before the storm meant that most would survive. Dan Rutherford, a marine surveyor on the BoatU.S. Field Catastrophe Team, estimates that 75% of the boats in the parking lot were repairable. Had those same boats remained in the water, all would likely have been bashed against pilings and sunk. Blocking the boats ashore averted another costly problem: pollution from leaking fuel.

It’s difficult to imagine docks that could be better sheltered than those at Columbia Island Marina in South Arlington, Virginia. The 382-boat marina is located in a basin that is surrounded on four sides by gently sloping banks and separated from the Potomac River by a long, narrow canal. During Hurricane Isabel, the boats at Columbia Island were well protected from storm’s wind and waves. The surge, however, was a different story.

All of the marina’s boats are moored at floating docks. During the night of September 19, the surge rose an astounding 14’, which in years past would have resulted in widespread damage when docks and boats floated free. But when the docks at Columbia Island were rebuilt several years ago, pilings were driven into the bottom that tower 18’ above normal water levels. As a result, Isabel’s powerful surge remained a comfortable distance—four feet—from the tops of the pilings. The docks stayed put and none of the boats were damaged.

As far as moorings are concerned, the times they are a changing. Ten years ago, Hurricane Bob swept up the New England coast destroying hundreds of boats, most of which had been on moorings. Some of the damaged boats came to grief because lines chafed, but many more were wrecked because the mooring anchors—half-buried mushrooms and inadequate dead weight anchors—proved to be woefully inadequate in the face of Bob’s wind, waves, and tidal surge. Then, as a sort of meteorological one-two punch, the Halloween Northeaster pounded the New England coast, popping out even more moorings.

The past decade has seen many technological advances in boating, not the least of which is a greatly improved anchor for moorings—the helix. Depending on the harbor bottom, traditional mooring anchors, both mushroom and dead weight, had tended to sit on top of or just below the surface. Theoretically, the holding power of a mushroom anchor can be increased up to tenfold once it becomes buried sufficiently in mud. In most harbors, though, a mushroom anchor might be buried a foot or two in a mud bottom and is usually canted to the prevailing winds. If a storm comes out of a different quadrant, the mushroom is easily popped out. Mushrooms also don’t do well in silt bottoms or in denser bottoms, like sand or clay. In the latter, the mushroom tends to sit on or near the surface and must rely solely on its weight to anchor the boat.

A dead weight anchor may gain some advantage from suction in a mud bottom, otherwise it’s holding power is completely dependent on its weight, or more exactly on it’s submerged weight, which in the case of a concrete anchor is almost half its dry weight.

Another factor is scope, which has as much to do with holding power of a mooring as the anchor itself. Studies have found that when the angle of pull increases to 25º, a mooring’s holding power begins to weaken precipitously. So in shallow harbors, where a scope of 3:1 can be had with, say, 20’ - 30’ of chain, the advantage of scope is all but eliminated in a storm by a combination of tidal surge and the high, pumping motion of waves.

Comparing the holding power of a helix anchor to a traditional mushroom or dead weight anchor is like comparing a wood screw to a thumbtack or paperweight. A study by the BoatU.S. Foundation, Cruising World magazine, and Massachusetts Institute of Technology (MIT) found that a 500 lb. buried mushroom could be pulled out with 1,200 pounds of pull (supplied by a 900 h.p. tug); an 8,000 pound dead weight (concrete) anchor could be pulled out with 4,000 pounds of pull. The helix, however, could not be pulled out by the tug and the strain gauge recorded 12,000 pounds of pull—its maximum—before a shackle was burst apart by the strain. Scope in each case was slightly less than 3:1. (In an earlier test, a strain gauge had registered 20,800 pounds before the hawser snapped.)

Installation of the Helix: The Key to it’s Success

Installation of a helix, unlike a traditional mooring, requires expertise and special hydraulic equipment. The anchors are made by A. B. Chance Co. of hot-dipped galvanized steel with 1 3/4”shafts and either 8”, 10”, 12”, or 14” diameter helices. Extenders can be used to drive the mooring further into the seabed for additional holding power. Royce Randlett, Jr., president of Helix Mooring Systems Inc., says the company has installed over 3,000 helix anchors plus a similar number of a smaller (5’ 6” with a round shaft) “lighter load helix anchor with a single helice. The latter is installed by a diver and is only suitable for smaller boats.

The helix isn’t infallible; there have been several cases where helix anchors have pulled out. In one case, the helix was being used to secure a 72’ sailboat in Marion, Massachusetts during an especially fierce northeaster. While a helix requires less scope than a conventional mooring, this helix had almost no scope because of the storm’s surge, according to George Jennings, who was then the harbormaster in Marion, and was pumped out of the bottom by the boat’s fore-and-aft rocking motion. In another case, a helix let go because it was installed by someone who was inexperienced and drove it only part of the way into a rocky bottom. One of the problems has been that the number of people who are qualified to install helix anchors; there are only 20 installers, mostly in the Northeast, with a handful in other states—Maryland, Florida, and Washington. Ham Gale, who installs helix anchors in the Annapolis , Maryland area, uses a specially-designed platform—a raft—for the hydraulic installation equipment that can be towed to the spot where the mooring will be installed. Two long metal pipes—called spades—at the ends of the platform are then lowered into the harbor bottom to anchor the platform and prevent it from twisting while the helix is being screwed into the bottom. The holding power of a helix is ultimately based on the density of the bottom and it’s depth into the bottom. Using a pressure gauge, an installer can estimate a helixes holding power by translating pounds per square inch to torque. If a helix goes into the bottom too easily, Gale says the installer can add an extender to take it