instagram pinterest linkedin facebook twitter goodreads facebook circle twitter circle linkedin circle instagram circle goodreads circle pinterest circle

DON'S LOG: stories, experience and advice

LAYING UP ON A HURRICANE MOORING DURING HURRICANE SEASON OR SURVIVING A HURRICANE AT ANCHOR

Effects of wind on 50ft monohull with a 60ft mast laying head to wind
Effects of wind on the achorline load of  50' monohull with a 60' mast laying head to wind. Note loads increase drasticallywith larger boats.

This is not a good idea as is illustrated by my loss of L’ll Iolaire in hurricane Ivan in Grenada in 2004. Iike most sailors felt that Grenada that had only been hit by two hurricanes, one in 1856 and in 1955 Grenada was basically south of the hurricane area. Every summer starting in 1996 we laid up L’ll Iolaire on a good heavy mooring, chain to a rope attached to a buoy. From the buoy to L’ll Iolaire two separate lines lead thru two separate chocks to two separate cleat bolted to big backing blocks. Lines were carefully cover with chaffing gear.

Grenada had been hit dead on by hurricanes in 1856, 1955, so I felt the chances of a hurricane hitting Grenada did not have to be considered.

If a hurricane passed north of Grenada, or a low came thru developing 40/50 kts of wind, L’ll Iolaire I felt would have no problems swinging on her mooring.

A good friend regularly checked the boat the mooring lines pumped the bilge. She was laid up for the summer, all sails removed and stored ashore.

All was well until Ivan hit. Amazingly L’ll Iolaire survived Ivan. I have seen a video, the winds were easing off, L’ll Iolaire was doing fine until a 50’ catamaran dragged down on her and started to demolish her. The load of L’ll Iolaire and the catamaran was too much for the mooring, L’ll Iolaire broke loose from the mooring , battered and bashed by the catamaran she sank.

No matter how good is your mooring, your boat will have little chance of surviving without major damage if a boat drags down on her.

What is a proper hurricane mooring?, huge anchor? Huge block of concrete? Sand screws tied together?

A proper hurricane mooring must stay in place in hurricane induced loads. Wind loads go up with the square of the speed. Look at the attached graph of loads( Kevin pls insert both of Scott’s graphwind vs pressure per sq in here)

windspeed.png

The below figures are the the calculated loads on a 50’ monohull with a 60’ mast laying head to wind. But boats will tack back and forth across the mooring line so loads will increase when boat is not head to wind.

anchorline_load.png

 

Windspeed Knots Anchorline load 50 ft monohull with 60ft mast
0 0
10 60
20 220
40 900
60 2000
80 3600
100 5500
120 7900
140 11000
160 14000

These figures are for a 50’ monohull, a multihull probably double or triple these figures. Obviously it is impossible to moor a multihull to withstand hurricane force winds as they discovered in Paraquita lagoon in 2017.

Basically you have to visualize your boat being picked up out of the water by your anchor lines attached to a big crane. Are your anchor lines strong enough? Will the mooring cleats and anchor windlass stay in place or pull out?

If after reading the above you decide to leave your boat on a hurricane mooring, pick an a anchorage that is well sheltered in the southern end of the eastern Caribbean islands. Install something that you feel will stay in place when loaded up to the load induced by a 120 mph wind 5170 lbs.

There are three options, huge anchor or anchors, huge concrete block or sand screws secured together to swivel to single chain.

It must be remembered that as the hurricane passes the wind will shift 180 degree. This may be gradual see Surviving Klaus, or almost instantons as happened in 1960 in Road Harbor Anguilla. The eye passed right overhead. The wind shift was so fast that the schooners at anchor were hit with a massive gust right on the beam. All the schooners were knocked flat, filled and sank.

If a huge anchor is found, it must be well buried, either towed in by a very powerful pull by tug or set by divers digging a hole and burying the anchor . With the wind shift will it slowly turn and hold? Or break out and bounce along the bottom? Some sailors recommend two anchors tied together with a chain, big ring, then chain to riser line . No swivel as they are a source of trouble, must be massive. You will be using ¾ or 16mm chain to heavy riser line so it will clear itself of twists.

3/4or 16 mm chain seems to be  the  largest size chain available in the eastern caribbean. It has a SWL of about 10,000 lbs, breaking strain is  probably four times  that so the  chain should  hold  an intermittent load of  20,000 lbs

In some areas they urge big concrete blocks but concrete is relatively light. A 1,000 lb block of concrete weights only 700 lbs in water. For this reason Ian Cowan urges loading into the concrete when casting with as much scrap iron as you can find. 

 

Having read yachting magazines since about 1942, and stories of disasters where in hurricane conditions big concrete blocks were towed across the harbour and boats either demolished of badly damaged, thus I have a low opinion of their use as hurricane mooring. Mud bottom, if left for a year or more they may settle into the mud and hold. On most bottoms concrete blocks just sit on the surface and slide once hurricane loads encountered.

To improve holding of concrete blocks, I suggest if being used in a soft bottom, make a mould in the shape of a trapezoid, with a pipe in the center running the full length of the trapezoid. Once lowered in place , air hose is connected, high pressure air 2,500/3,000 psi is blasted thru the pipe, trapezoid should settle into the bottom. How deep it will settled depends on the type of bottom.

The concrete block should be loaded with scrap iron, Sam Verity   sam@cms-sl.com . He is Bu a higly regarded marine construction contractor in St Lucia states there should  be a full 3" of concrete between the iron and  the  edges of  the  block.

I recommend  about 3' of galvanize chain, long  link if  available, imbedded in the broad end with a couple of feet  extending to be connected  to a chain that is  connected to a  riser line  to a  buoy..

I say this as  my Dragon Gypsy Anker and Jensen 1933 the oldest dragon in the world still regualry racing, ride on a very  large  concrete block with 3/4" long link ships  chain cast  into the block. We  discovered this as an abonded mooring that must be 30 or more years  old.

In may 2020 it was lifted and  placed on the  pier  for  checking. It  was  a  concrete block  4 1/2' square,  9"thich thus weights 1,100 lbs when out  of water, but only 560 in water.

The chain is embedded in the  concrete. There is no indication  of  the  chain rusting  in the  concrete with the  rust   expanding and  cracking  the concrete and pulling loose.

The block had  settled into the sand so much that it took 2 1/2 tons  to  pull it free. The corner of Glandore harbor where Gypsy lies  has  been silting badly  for the last fifteen    years. Hopefully when re set the  silt will rapidly bed down Gypsy mooring

Sam  does not like this idea as  he feels that the chain will corode and start destroying the concrete. If it is  galvanized chain buried in concrete, in the light of the above I do not think corrosion of chain in the  block will be a problem.

Sam  recommends a tube running thru the  concrete  block, chain run thru the  tube and  secured  and lead back on itself. The  two ends are then secured to a big ring, and  riser chain secured to  the  ring by a bow shackle, NO swivel. 

Sam, Ian, and  Don Street all recommend  avoiding swivels  as they too often cause  problems.

The  chain thru the  block is  heavier chain than the  riser chain.  When the  riser chain has  reache the end of its life, it is replace.  Chain in the  block lasts much longer than riser chain. When the  chain gets old,  mooring lifted a new  chain run thru the tube and  block ready for another few  years  service.

Sam has used this rig in St Lucia for  years   but the mooring  have not been huge  hurricane moorings.

 

When the trapezoid  block is lowered into the bottom , the pointed end will allow the block to sink into the soft bottom. An air house is then connected to the pipe, high pressure  air blown thru displacing, mud, clay and allowing the tear drop shaped casting to work its way down in to the bottom.

Another option, four sand screws. Contact rustybvi@gmail.com Rusty Burns has  been setting and maintaining sand screws for  Mor secure  for ? years. The mor secure sand screws are designed to hold a  60' monohull in 40kts  of wind. They have  stood the test of time, failures of Mor secure moorings are  practically  unknown.

The load on the anchor line  of a  50' boat  when it is  blowing 40 kts is  roughly 900lbs, a 60' boat ?

Rusty states the  biggest  sand  srews he can set with his gear are ? which the manufacturer states should hold     load if driven in to  sand or solid earth.

 Ir must be remembered  when hurricane loads come on the vast majority of the load will be on only two sand screws Connect all with long link chain, swl 9,180 breaking load  about 36,000 kg.

Long link chain should be uses as it is stronger than normal chain. Being long link it is easy to secure shackles to long link chain. However finding long link chain in the caribbean will be difficult and possibly  impossible.  It may only  be available in long lengths.

The largest  sized chain that is redily  available in the eastern Caribbean and can  be bought  in relatively short  lengths cut  from long length, is 3/4 and  16 mm.  IWW St  Martins  keeps  this in stock.

Join the four lengths of chain to a really big ring, to really heavy chain, 5/8 or 16 mm vwhich is the largest size that can be obtained in the caribbean. Good chain will be tested chain, tested to about 10,000 lbs, breaking strain about 4 times that.

As the wind shifts, the loads on the sand screws will shift but if four are connected the load will always be on two sand screws. The long link chain, size? length dependent on water depth, is joined to riser line size?attached to a buoy. Riser line should be polyrene as polyrene is more resistant to chafe than nylon.

Mooring buoy preferably of the type you can pass the mooring line thru. Once thru the buoy make an eye splice around a stainless thimble. Thru the thimble run two separate lines, each one twice around the thimble before securing back on itself. Run the lines port and starboard, the largest diameter that will fit thru your chocks and allow room for chafing gear. Then secure the two buoy lines to two separate mooring cleats, samson posts or anchor windlass. Do not rely on the anchor windlass to take the whole load as on modern yachts all to often the windlass and large portion of deck departs in storm/hurricane conditions.

?   have been left in the above as hurricane moorings must be designed for the boat and to the maximum wind velocity the boat owner figures will occur in his or her anchorage.

Hurricane moorings are not a DIY project, it is a project to be undertaken by good marine contractors.

Regarding chain, shackles, riser line , bouys I advise contacting Ian Cowan of iwwsl.ltd@candw.lc

Ian arrived in the Caribbean in 1970 and was hired by the late Bill Stevens commission 15 Out Island 41 to add to his expanding bare boat fleet. Once this was done he hired Ian to run his Stevens Yachts charter fleet that consisted in bare boats and a number of fully crewed charter boats. In the 70s and 80s the three leading bare boat charter companies were Stevens Yachts, CSY and the Moorings. Ian was in the bare boat business until 1997 when Sun Sail which had purchased Stevens Yachts, moved from St Lucia to St Vincent. Ian left Sun sail and ran the yard at Rodney bay from 1998 to 2002.

In 2003 Ian, his wife Rosemary, plus some friends in the states formed IWW St Lucia ltd. Ian has been manager of IWW St Lucia. Because of his long and varies experience he has an encyclopaedic knowledge of anchors, chain, swivels, shackles and line, and how to use all this properly. He also knows what is available in the eastern Caribbean and /or can be ordered.

I advise consulting with Ian, then order thru Ian, or Julian@islandwatetworld .com. They can have whatever you order to their stores scattered thru the eastern Caribbean or can arrange shipment to island on which they do not have stores

Remember when the hurricane passes the wind will switch, speed of the switch is dependent on the speed of advance of the hurricane and the distance between you and the center of the hurricane. Because a wind shift is inevitable, when leaving a boat on permanent mooring during hurricane season, when no one will be on board, the mooring should be a single chain as described above. If this is done , as the wind direction shifts the boat will weather cock be head to wind. If a boat is on two anchors a the wind shifts the load will come on one anchor, line to the other anchor slack. The single anchor will be overloaded and drag or anchor line will break.

To do any of the three options offered above, to be properly done, they are not DIY operations. They must be done by professionals.

When the cost are all added up, I feel you are better off hauling your boat and having her properly laid up ashore tied down and chocked to withstand a hurricane. See section Properly laying up ashore.

If you decide to lay a hurricane mooring for advise on chain, shackles, swivels, and line either available in the Caribbean or that can be ordered with a fair degree of reliability for its delivery I recommend contacting my old friend Ian Cowan iwwsl.ltd@candw.lc. I say this as I have known Ian since he first arrived in the Caribbean in 1970. Details of his career are noted above

To have a reliable contractor to lay a hurricane mooring I recommend Sam Verity, sam@cms-sl.com.

In hurricane alley if you decide on sand

He is a highly respected marine contractor who has done many projects in St. Lucia. He probably will not want to undertake projects outside of St Lucia but having been in the marine construction business for ? year he is able to recommend other marine contractors on the island where you plan to lay your urricane mooring.

If you decide to go the sand screw route Rusty  Burns rustybvi@gmail.com is the  man to contact

If you are caught out by a hurricane, and can not head south to avoid the hurricane, read section Surviving Klaus to see how Iolaire survived 80 kts of wind anchored on the north side of St Martins.

If against my advise have laid a hurricane mooring and are leaving your boat on it, then strip the boat down to minimize windage. Sails and dodger off , all loose gear removed, all halyards except the main halyard pulled up to the top of the mast. Organize with a person or yard to regularly check the lines to make sure there is not a chafe problem and check the bilge. Automatic bilge pumps are very suspect. I can remember well over a dozen insurance claims I have been involved in settling caused by failure of automatic bilge pumps.

When all the above is done, clutch your rabbits foot, bow east to Allah, get your hindu and rosary beads going around like bicycle chains and hope a hurricane does not score a direct hit on your anchorage.

Regarding going to a so called hurricane hole and surviving on the yachts normal anchoring gear. The chances of survival without major damage are minimal. Even if your anchor or anchors hold the chances of boats dragging down on you are high. If your anchorage receives a direct hit of a hurricane, re read the above and the loads on anchor gear at various wind speeds. Your chances of staying put are minimal.

I have been very lucky. I have survived six hurricane on boats, but in all cases we did not suffer a direct hit, we were on the edge of the hurricane. In one of the cases. we were the only boat in the anchorage so no danger of boats dragging down on us. In the first hurricane in City island, we were lucky. We had the engine going to ease the load on the mooring line which we were told was attached to a 1,200 anchor that we were slowly dragging. One boat, a big water boat that carried water to big yachts, broke lose and was drifting down on us. I put the helm hard over, we took a shear to port. The water boat came by so close we could have stepped aboard.

In the  other four hurricanes the  boats and  I have survive, we did not receive a dead hit, only a very hard knock.

In Klaus, We were on the north side of St Martin , on two anchors spread out in a Y, wind out of the south, we felt we were in good shape. The hurricane was south of Puerto Rico. Hurricanes in the low latitudes always go west.

But we discovered Klaus was heading NE( subsequently using the NOAA hurricane book 1851 to 2006 with loose pages thru 2019 was only the second hurricane to do this since 1851) Our wonderful anchoring under the lee of St Martin would become a deadly lee shore anchorage when the center pasted north of us and on to the NE.

As the hurricane approached, the wind clocked, so the line to the port anchor went slack, all the load came on the starboard anchor. We were anchored in only 12 ‘ of water, so we dropped another anchor on the starboard side, slacked the line to the anchor that had taken the load until enough line was out that the load was even between anchors 2 and 3. As the wind clocked more anchor line to anchor 2 went slack, so we dropped anchor 4 and slacked line to anchor 3 until we were anchored on anchors 3 and 4. We continued this until we were riding on anchors 5 and 6 facing due north as the hurricane passed.

The biggest worry was the rusty interisland ferry that had anchored astern of us was now dead to windward of us. If she dragged or anchor chain broke we were finished.

But the gods of luck were on our side, the rusty freighter stayed in place.

How hard did it blow? The airport anemometer blew away at 72kts!!!

When Klaus passed on, swell went down, we retrieved all the anchors with no problem. We and no crossed hawse, and the first anchors we dropped were now right under the stern.

If you are unfortunate and are stuck at anchor, can not move and a hurricane is approaching, start preparing to try to stay at anchor and not drag across the harbour. Set your two biggest anchors out in a Y in the direction the wind is expected to be. Then assemble all spare anchors, line and chain so when the eye of the hurricane passes, and , the wind shifts and the loads on the anchor lines shift, spare anchor or anchors can be dropped. It is worthy of note that the aluminium fortress anchors are excellent spare anchors as they can be disassembled and stowed in a small space.

A good big fortress anchor once set will hold an incredible load. It disassembles and stows in a bag taking up relatively little space.

The danforth anchor, cross arms on both sides of the blades can be cut off, the hole the cross arms and base of the blade can be threaded, a stud fitted to the cut off cross arms, cross arms taped to the stock(photos here from osy 1) and anchor stowed until needed. In hurricane season I feel a boat should have on board a minimum of four or five anchors.

Install plenty of chafing gear on anchor lines. Duct tape makes excellent emergency anchor line chaffing gear. Anchor windlasses have a bad habit of coming adrift when heavily loaded. The same is true of mooring cleats. If the least bit suspicion of either or both, secure anchor lines to mast or run back aft and secure to the biggest sheet winches via a tow boat/lightermans hitch. Illustrate if possible.

Usually as the hurricane passes the wind gradually shifts. If the eye passes overhead, a calm will exist for a short while then a 180 degree wind shift with a full hurricane blast. This can happen so suddenly that it can be disastrous. Doctor Tattersall, reports that Mr Gumbs the owner of the schooner Warspite the supplied the light house keepers on Saba rock, said that in hurricane Donna a catagory 5 hurricane in 1960 that as the eye passed, the wind shift was so fast and hard, that the schooners anchored in Road Harbor Anguilla, had not yet swung, wind caught them on the beam. All capsized and sank!!!

After reading all this I hope you will take my advises and 48 hours before the hurricane is to hit your area, you up anchor and head south “be where the hurricane aint! “

If you are caught and must ride a hurricane out in an anchorage, strip the headsail, or head sails off the foils and stow below. If there is a hanked on stay sail, leave in place but tie down firmly. Mainsail, remove and stow below and rely on engine in case of emergency, or leave in place for emergency if blown off anchor or anchors have to be dropped? Skippers decision but if main left in place it should be double reefed before securing. Needless to say secure with extra sail stops /ties/ gaskets (three names for the same thing) or line to make sure it does not go adrift. Run halyards up to top of mast to minimize windage. If double headsail rigged with hanked on stay sail, secure halyard to a strong point so it is available if staysail needs to be hoisted, and main halyard so you can send a crew aloft to retrieve halyards after the hurricane has passed.

On ketches, leave missen in place, reefed and well tied down. Yawls the same. Missens on yawls usually do not have reef points as they are so small they usually do not need to be reefed.

Make sure fenders are ready and easily accessible, with lanyards installed at both ends.

Then lay out face mask and snorkel as when it starts blowing 80 kts, and rain, it is impossible to see and breath unless wearing a face mask and snorkel.

When it really starts blowing, warn everyone before they go on deck, do not stand up, crawl around on hands and knees.

Before it is blowing hard have the entire crew sit down and eat a really good big dinner. The put a big pot of stew or soup on the stove to re heat later on. If thermos available, coffee or tea as crew prefers into pre heated thermoses.

Then best wishes

,

Be the first to comment