This blog post describes why we decided to build a mooring in Luperón, Dominican Republic (DR), how we arrived at a design, and how we installed it. My intent is not to describe all ways to build a mooring. Instead, this Long Read describes the mooring that we built for our St. Francis 50 catamaran in Luperón as we waited out the 2016 hurricane season.

In this Long Read

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Why We Built a Mooring in Luperón

A couple of factors led us to believe that we needed a mooring. First, we learned by talking to other cruisers that the Luperón harbour would be hard on our ground tackle (anchor, chain, swivel, and bridle). The Luperón harbour is thick with silt, and barnacles grow quickly.

Boats were dragging

Another compelling reason to get a mooring was seeing that several boats on for-hire moorings had dragged. In fact, a few weeks ago, we watched a boat drag across the harbour. The boat that dragged was on a rented mooring, anchored to a concrete block.

Watching the boat drag across the harbour made us leery of using an existing, for-hire mooring. We weighed our options and determined that we’d be best to build our own. Mushroom anchors were not available. Other than using heavy engine blocks, we considered anchoring ourselves to the sea floor with concrete blocks or anchor screws.

Problem with concrete buoyancy

It is interesting to note that concrete weighs less in water than on land. The simple explanation is that concrete is affected by buoyancy (just like everything else), but concrete blocks are large so they displace a lot of water. Blogger and PADI Instructor Chris Sullivan describes this phenomenon in greater technical detail in his blog post, “Buoyancy of  Concrete“.

We decided on the anchor screw as being more permanent, knowing the boat that dragged was on a concrete block mooring. One negative we had heard about anchor screws was that they could work loose over time. To combat this we decided to use three anchor screws arranged in a triangle.

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Our Three-Point Mooring Design

Anchor screw design

We had our three anchor screws constructed at a local welding shop. The screws are ten-foot lengths of 1-inch-diameter rebar with 1/2-inch thick, 24-inch-diameter steel augers welded to one end of the rebar and a bent rebar ring welded closed at the other end. These anchor screws are then screwed into the sea floor by two divers until all that remains above the sea floor is the ring.

Our anchor screws were ten feet tall with two, 24-inch-diameter augers. We unfortunately lost our photos of our actual anchor screws when Rick’s phone was damaged.

A three-point mooring is pretty secure. Using three anchor screws ensures that at almost all times the load will be shared by at least two of the anchors. In fact, here is how the sea bible Chapman Piloting: Seamanship & Small Boat Handling (1999, 63rd edition, p. 274) describes “A multiple anchor system”:

One hurricane that ravaged the North Atlantic Coast swept through an anchorage in the New York area and tore almost every boat from its moorings. Only two survived. What these two had in common was an “unconventional” mooring system — three anchors bridled to a common center, with chain and pennant leading from that center point to the boat.

We sought advice from locals, cruisers, and experienced sailors

So, this is what we decided to build and what drove the design plan for our mooring. The extra two screws cost only about $175 more than for one. Rick spoke to other cruisers as well as the service boat operators in Luperón harbour. Rick also sought input from our friend, Dave Houston. Dave is an experienced sailor and former owner of the St. Francis 50 catamaran (O’Vive).

The initial design plans were vetted by industry expert Pat Reischmann. Rick also received input from Greg Kutsen of Mantus Anchor. Our mooring was so robust that it impressed sailing celebrity Bruce Van Sant, who met us on our catamaran one afternoon for lunch. In an email commenting on the design, Bruce wrote:

While you’ve done a great job and overkilled it (if that’s indeed possible to overkill on a mooring), be aware that the danger in Luperón comes from the rampaging flotilla of unmoored boats dragging into you. They’ll fine tooth comb the bottom with their dragging anchors and make a fine mess of tackle-tangled boats which can wrap around your steady-moored boat and beat it to death from all sides.

Mooring design resources

Rick’s research helped shape the design plan and specifications. Some useful resources include:

• Chapman Piloting: Seamanship & Small Boat Handling (1999, 63rd edition, p. 274, “A multiple-anchor system”)
• Monmouth Boat Club Moorings (PDF)
• Mooring — Safe Moorings from INAMAR (INAMAR is an insurance company, PDF)
• Minimum Standards for Single-Point Moorings (Deep River Harbour Master, CT, PDF)

Schematic

Below is the finalized plan of Aphrodite’s mooring that Rick created using Visio. The same plan is available in PDF format here.

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Building and Installing the Mooring

Finding quality gear in the DR

To source the materials in the DR, there were a few challenges that Rick faced, including:

• trying to find materials in a foreign language — most people speak Spanish, but not English, in the DR. Rick sometimes relied on his taxi drivers to act as interpreters. In one case, a taxi driver and salesperson insisted 3/8-inch G30 chain was sufficient for our boat. G30 is a general-purpose chain, and would have been unsuitable in the 3/8-inch size that was available. Nonetheless, the taxi driver and the chandlery salespeople were adamant that “that was what all the boats here are using.” If that’s true then that’s a scary thought. We didn’t buy the G30 chain.
• trying to get properly sized chain — we eventually had to settle for 1/2-inch G7 transport chain with a chromate finish. G7 chain is exceptionally strong and it will be good for many years, but it won’t last as long as it would if it was galvanized.
• buying line for the pennant — Rick wanted 1-inch or 1.25-inch line, but the stores would only sell a minimum of 300 feet for about $2,500 U.S. We only needed 60 feet. This is why we settled on the rather unconventional approach of using two pairs of bridle lines of used 3/4-inch line.

In Luperón there is one second-hand chandlery.

In our search for materials, Freddy’s chandlery and the local hardware store had smaller chain, shackles, and swivels available. But they could not provide us with the components suitable for our boat. Consequently, we made several trips to Puerto Plata and Santiago to investigate what was available and to buy materials.

The happy news is that we were able to acquire all of the materials that we needed here in the DR.

Assembling the bridle

In preparation for the bridle, Rick spent three hours smoothing the ring-to-ring swivel with a Dremel tool. He wanted to be sure to minimize chafe between the lines and the metal.

Here is a picture of Rick at work, smoothing one end of the swivel with a Dremel tool. Actually, he started with the Dremel, then switched over to his more powerful drill.

Here is a picture of the finished swivel with the lines attached. These lines are called pennant lines.

The pennant lines form a bridle. The bridle acts like a set of reins for our boat. The bridle offers stability and prevents the boat from twisting around in the wind and waves. There are two ends to the bridle, which Rick refers to as “legs” in his design plan. Here is a picture of one side of our bridle, which will attach with an eye splice (loop) to a cleat on our bow.

So far, the design — both below and above water — looks pretty robust to us. But we felt it was important to consider the optimal location for our mooring in the harbour.

Choosing the location with input from Chris Parker, Marine Weather Center

To determine the best spot for our mooring, Rick wrote to weather expert and sailor, Chris Parker. In his email to Chris, Rick highlighted his assumptions and wrote:

Hurricanes would likely approach from points south, south-east or east.

Hurricanes approaching from the south would likely be deflected to the west by the mountains before reaching Luperón. In this case, we would experience winds from the east, but they would be reduced somewhat by the mountains.

If hurricanes passed by us heading to the north, to the north-west or to the west then we would likely experience winds from the north, north-west and west.

Based on the above, it is my understanding that it would be best to construct our mooring on the north-western side of the harbour, rather than the eastern side.

A picture was sent to Chris Parker, similar to the one below.

Chris agreed with Rick’s assumptions regarding winds, and responded to his email as follows:

Rick:

Yes, you are absolutely correct. Strong winds with a Hurricane would tend to blow mainly from N & W directions, with lesser winds from other directions possible depending on the track of the LO.

From Chris’s reply we determined that the optimal spot for our mooring was the north-western side of the Luperón harbour.

Installing the mooring

With the help of Handy Andy, who operates one of the service boats in the Luperón harbour, we chose a spot for our mooring. Water depth was measured the traditional way — dropping an anchor and measuring the rope required to meet the sea floor. The water measures 18 to 20 feet deep in the area where we installed our mooring. A depth gauge would have been useful, though not essential, for this activity.

Our riding chain is 20 feet. Rick would prefer that the riding chain be 30 feet, and may consider adding more chain later. A longer riding chain is more in line with the recommendations found online and elsewhere. But bear in mind that we are close to other boats in the harbour, and we do have 50 feet of chain and bridle between the boat and the sea floor.

Underwater video

The following video captures the components of our installed mooring as they appear below the water.

At times in the video there are glints of red on the chain. This is the reflection of our camera’s red recording light reflecting off the chain and shackles.

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Safety, Weak Points, and Cost

Every mooring depends on the quality of the materials and the care taken in planning. We know that the safety of our mooring is undercut by the use of rebar of unknown origin, Chinese-made steel chain, shackles and swivels, and the proximity of nearby boats. Because we are in the DR, we don’t have access to the breadth of parts available in North America.

Still, we expect that this construction will last for several years. If we had had access to U.S. steel products, then our mooring would have been built to last longer.

Engineering safety with anchor screws

We were surprised to learn that the shop had never been asked to completely close the loops at the top of the anchor screws. Before we asked them to weld the loops closed, there was at least a one-inch gap remaining. Surely this gap would allow a chain to slip from an anchor screw? We wondered about the safety of other moorings, and were glad that we asked to have the loops closed on our anchor screws.

Costs

All of the parts for our mooring were purchased in the DR. The total cost including parts, labour and three taxi trips to Santiago and Puerto Plata was $1,640 U.S. While this may seem steep, we plan to stay here until the end of November 2016. The cost for the remainder of our stay works out to $14 U.S. per night. Our intent is to sell our mooring to another cruiser who is staying long-term in Luperón. While it would be interesting, we have not priced out what it would have cost us to buy the parts in the U.S.

Many thanks to Handy Andy and his amazing team for installing our mooring and helping us see this project through!

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Related post:

Luperon Long Reads — Waiting Out Hurricane Season