Anchoring System aft deck

Aft showing bridle to ball float which keeps the anchor rode safely away. Before I installed this keep away system, in light winds the current would sometimes move the boat over the slack anchor rode and get it tangles in the rudder, Now the rode is pushed ten feet away from the rudder in light conditions. In heavy winds the pull on the bridle takes the strain off the hose.

Here the bridle is stowed for sailing. The rode is attached to the back stay and the tail is stowed in a deck locker which can hold 100 feet of rode.

Coming up the mooring spot

To anchor, I lower the bridle until the ball float touches the water, then pay out the anchor rode over the roller at the stern until it fully deployed, usually 100 feet of 1/2 inch nylon for 12 feet of water, another 100 foot section is added for 20 feet of water. I can see the bottom to drop the anchor right below me onto a sand bar. Since the driver is standing next to me I can give quiet instructions to power ahead as I pay out the rode and until the strain comes on the bridle. Once the anchor begins to bury, I can relax, knowing that no matter which way the wind blows the pull will always be directly along the rode which buries the anchor more. All the time at anchor the wind pressure on the stern drags the anchor deeper.

This is showing the rollers and guide to keep the bridle from chafing. There has been no wear on these lines in 15 years. The rubber wheel keeps the bridle from rubbing against the stern in light winds and contrary currents (in a river.)

Anchor Davits and stowage

As you can see the Fortress 37 anchor stows aft. Th anchor roller here is used only to drop and lift the hook. This anchoring system was by far the best upgrade to the boat. The boat sits quietly in strong winds and does not yaw more than 2 degrees when at anchor. In a strong gale the boat is very docile and always points the stern into the wind. Anchoring off the stern reduces the area of the hull exposed to the wind by 30% (caused by yawing to the wind off the bow.) This means that the anchor system can withstand loads 30% higher before the anchor drags.

A sailboat naturally wants to sit with its stern to the wind because most of the windage o f the boat is the mast which is forward of the center of lateral resistance of the keel and hull. You can test your boat by letting it drift downwind with no sails up. It will usually drift stern to the wind. When you anchor off the bow the boat is continually trying to turn with its stern to the wind and that is why it yaws at anchor. This yawing pulls on the anchor which is turned this way and that and it can be pulled out. Also the rode chafes at the bow, and in a blow it can chafe through.

With stern anchoring there is no chafe. The pull is always from the same direction.

Movie showing boat yawing when bow anchored

Buoyancy

There is another consideration: In a storm at anchor the boat anchored by the bow will have the bow continually swept with waves because there is not much buoyancy due to the narrow bow section.

The pull of the rode which can be very heavy with an all chain rode which most people seem to prefer (big mistake) keeps the bow depressed, so the foredeck is swept with water, which makes a trip to the bow to check the anti chafing gear hazardous.

On the other hand the stern has a tremendous buoyancy and lifts to every wave, and the cockpit stays dry (unless it is raining hard.) It is easy to check the anchoring gear without leaving the cockpit.

Hurricane anchoring

Here is my boat at anchor for hurricane Floyd.

I remember coming back to the boat after hurricane Floyd. My boat was at anchor on a sand bar that had 15 feet of water over it at low tide, and quite a way from the marina. As I entered the marina complex I could see boats sunk at the dock. Some boats were aground mast tilted over. I dinghy’d out to my boat and found it was dry and nothing damaged. The cup of tea on the countertop by the sink was still half full of tea, as I had left it. Obviously the boat had been stable.

In Grenada I left it at anchor from the stern for three months while I went home. It was perfect when I got back.

Leaving the mooring

To leave the mooring we back up to the anchor by puling on the nylon rode, or by backing up with the engine until we are over the anchor. We haul it up (30 lbs), stow the anchor on its stern davit, draw up the bridle and attach it to the backstay, then hoist the jib and sail off the mooring. By the time we pull up the anchor the boat is already drifting slowly downwind pointed in the right direction.

Considering the boat design

Strange that most people don’t consider the anchoring system before buying a boat. You will spend ten times as much time at anchor as you do in the Ocean. You will worry more about anchoring than sailing. I have been hurricane anchored for four near misses, and never worried about the boat. I had to evacuate and go inland, so couldn’t watch the boat. Every time I returned, I found my boat safe and dry, while others were sunk, or blown onto the land. If you have watched the horrors of the aftermath of storms in the pond at St. Martin, in Grenada BWI, and Charleston after Hugo, you are bound to be fearful for your own boat.

If you can’t haul out the boat for a hurricane, you can anchor off the stern. But

You need to have a boat with place for anchor equipment, winch and davits off the stern. And one that has a counter not an open cockpit typical of charter boats.Not a flat stern that the waves will bang against.

You could set up the bridle on the stern and drop the anchor off the bow, and walk it around to allow the boat to hang of a stern anchor.

Don’t use chain rode. That should only be used for deep water over 100 feet, where the catenary provides some cushion from the shock load of waves hitting the boat. For shallow water you must build the elasticity into the system with nylon that stretches. In shallow water the chain will become bar taught in a blow and will jerk hard on the anchor and pull it out, or the links could snap. You need to use elastic anchoring where the nylon rode will stretch to absorb the shock of the wave and keep the shock load off the anchor. Never anchor in any place where there is coral or sharp rocks, and you won’t need chain for chafe protection. If you are in an area where the rode is likely to fray use just ten feet of chain at the anchor end.

Always anchor on firm sand to weather a storm. Soft mud is useless as a holding material. Hard clay is great for holding but very hard to get the anchor to bury because a sailboat has insufficient engine power to bury it.

Don’t leave your anchors in the bow roller when sailing in the ocean.

If you are sailing to weather for a long period, the constant crashing of the waves into the bow will damage the bow roller and the deck fittings. On my boat the aluminum casting cracked, and the bow roller was bent when I was trying to escape hurricane Alma and had to go to weather for two days in heavy seas. Stow bow anchors below when at sea.

Anchors are okay on the stern as it is protected when going to weather, and when going downwind waves never break on the stern. The propane tank is on the stern and has never shifted at sea, and waves never even wet it.

For my introductory PDF on stern anchoring click here SternAnchoring.pdf.

The port and starboard winches here are used for spinnaker trim at sea, and as anchor deck cleats when at anchor. A bridle runs from these winches to the float through tubes composed of electrical conduit inside heater hose. The bridle keeps the hull away from any anchor road when winds are light and the current is moving the boat around.

RTN