How to Build a Mooring

Though the basics remain the same, there are several variations to building a mooring. This article outlines our recommended approach for moorings on the Hudson. Please note, our descriptions and recommendations do not imply any NBC liability. You anchor your vessel at the Nyack Boat Club at your own risk.

Your mooring is built from an anchor, a bottom chain, a top chain, pendants, and a system to pick up your pendants and keep them afloat. Please look at the following chart. On this chart you can see the sizes for the various parts of your mooring based on the weight and length of your boat. Not all boats are the same, if your boat length is in one category and your boat weight is in another category please call us.

The Short Story:
Attach the end of the bottom chain to the anchor. Bottom chain is 30 feet long. Use a shackle one size larger than the bottom chain dimension. If needed use two shackles, another larger shackle to adapt to the very large diameter on the neck of the anchor (commonly needed with a Dor Mor).

Add a 5/8" drop shackle to the bottom of the chain or one of the bottom shackles for the MC to use to drop your mooring. Keep the pin out and no need to wire this shackle.

Attach the other end of the bottom chain with a shackle to the lower swivel. Use a shackle and swivel dimension one size larger than the bottom chain.

Attach the other end of the swivel to the top chain (top chain is 20 feet long). Use a shackle dimension one size larger than the top chain.

Attach the other end of the top chain with a shackle to the top swivel. The top swivel and shackle dimensions are one size larger than the top chain. If your top chain is 1/2" the top swivel and the shackles that attach to it are 5/8".

Using a shackle attach the other end of the top swivel to your ring (or diamond).

Attach each pendant thimble to the ring using shackles that compliment the size of the shackle at the end of the top chain.

Either the pick up stick, the buoy/ball, or both, should have a line with a clasp. The ball line should be well shorter than the pickup stick. One or the other lines will wrap the the two pendants together when they are in the water. Typically people tie the ball with a short line to the one of the pendant loops, and then tie the two pendant loops together with the longer pick up stick line and clasp, taking the clasp and line off when the pendants are secured to the boat. This way the pendants will not sink the pickup stick, the ball keeps it all afloat. All shackles should be tightened and wired with stainless steal seizing wire. Use a small crowbar or large screw driver and a large adjustable wrench, or pipe wrench, to tighten the shackles.Anchors:

According to the House and Ground Rules, two types of anchors are acceptable at Nyack Boat Club: an american made mushroom or Dor Mor.

We strongly recommend Dor Mors. Mushrooms will often wrap, requiring you lift and reset the mushroom. If the wrap is really bad, the bow of your boat can be pulled under the water. Mushrooms do have good holding power but it's not worth saving the money. Get a Dor Mor. It's unlikely you can find a new american mushroom in any case.

Dor Mors are american made Pyramid anchors. They have a really short stem and the anchor is one piece. Unless you are unlucky enough to drop the anchor on a rock, the pyramid will bury itself in the mud, entirely, including the anchor shackle. You can get more info about, and order, Dor Mors here. Mud preserves chain and shackles. We have been setting and pulling Dor Mors for a few years now, they indeed bury deep in the mud and have excellent holding power.

The official H&G rule:

Moorings which were deployed for the 2012 season are grandfathered for subsequent seasons provided the chain and hardware meet or exceed Club recommendations. Any replacement mooring base purchased from March 7, 2013 forward, and any mooring base used by a member who is new to the mooring field in 2013 or thereafter must either be a Dor Mor or a standard or counterweighted mushroom of US manufacture, or a professionally set Helix of US Manufacture. Iron or concrete blocks may not be used. The Mooring Committee shall enforce this rule by means of an annual survey that must be completed each year by every member who applies for a mooring spot.

Chain:
Bottom Chain must be 30 feet long. Top Chain must be 20 feet long. Together that's 50 feet of chain. All moorings at NBC have 50 feet of chain. The bottom chain creates catenary. In a heavy storm your pendants are the weakest part of your mooring, the first to break. By having bottom chain so heavy so that it hangs with a curve when lifted, or so heavy that not all of it leaves the bottom, it acts as a spring, allowing some part of chain to flatten, or lift, in heavy gusts and then falling back down after the gust. This zipper like action keeps the pressure from the wind gusts off the pendants. If you skimped on the anchor size make it up with bottom chain. Don't over do it though, try to stick with the chart.

Swivels:
There are two swivels shown in our diagram, the top swivel is the most important and you can not leave that out. That said we recommend including both swivels a shown. The Hudson River is a tidal estuary that changes current direction twice a day. This induces twist in your chain as the boat will tend to rotate around your mooring with each current shift. The swivels release the twisting from this rotation. Again, the top swivel is mandatory. The middle swivel will release any twist being sent down the top chain preventing translating the twist to the bottom chain. Though Dor Mor suggests that larger moorings, those with 3/4" and or 1" chain, don't need the middle swivel as the chain is just too heavy to twist, it's still recommended (note - this is a place that some have choosen to save some money). We have pulled, moorings with 1" bottom chain, without middle swivels, and found a great deal of twist in the chain - use both swivels.

Pendants and rings:
You should have two pendants. Be sure that your pendants have thimbles at the end that attaches to the ring. Usually they are attached using shackles but we recommend looking for a source who sells a double pendant pre-attached to some kind of ring (usually a pear or diamond shape). NBC has been using RW Rope for the guest moorings but they are nylon and not polyseter. You should try to find polyester NOT nylon pendants. Nylon will stretch in heavy weather increasing the chafe. In any case this system is simpler and leaves out two shackles. Be sure to include chaffing protection on your pendants. Hamilton Marine also sells a nice alternative using Novablue pendants.

Also you might want to consider new england rope cyclone pendants, they extend the pendants with a dyneema system that has no strech and is very strong. I bought mine from jamestown distibuters but you can also find them on Defender. Not sure you if you can purchase directly from new england rope.

Buoy Systems:
There are basically two main types of systems: one where the ball stays in the water and one where the ball comes out of the water. The latter is what is described at the top of this article.

System where ball stays in the water permantly attached to chain -
Pro:
There is no weight on the pendants as the top chain is held afloat by the ball at all times.

Cons:
Your top chain will degrade faster due to being held at the top of the water where there is greater oxidation.
The ball will rub against your boat when the tide changes, potentially wearing the hull finish.
The pendants can get caught under the ball in slack tide and get cut up on the seizing wire and shackles.

System where ball comes out of the water -
Pro:
None of the cons mentioned above. More chain is kept in the mud reducing degradation and wear. No chance of getting pennats wrapped under the ball, no rubbing on your hull.

Cons:
If you have heavy top chain it can be difficult pulling up the pendants, especially at high tide. You might want to consider longer pendants if you are doing this. A good way to extend the length of the pendants is to add dyneema pendant extensions.

You must have a ball, no the pickup stick is not enough, it can be pulled under the water by the weight of the chain and pendants, and at some point your pickup stick will break or come undone.

Shackles:
As mentioned the shackle sizes should be one size larger than the chain they attach to. Also notice that in the short description at top we suggest using the same size shackle between the chains as between the anchor and bottom chain. Shackles wear out and might need to be changed before your chain. By having the same size shackle at both ends of the bottom chain, each year you can easily pull the chain up for inspection. Inspecting the shackle between the top and bottom chain is a good indicator of the condition of the shackle at the anchor. If the one between the chains is rotted, likely you need to lilft the anchor and change the shackle at the other end of the bottom chain as well.

Rigs should be inspected each year. Pull the chains up to the bottom swivel and inspect all shackles and swivels. Change any component that needs replacement.

Note: Erinie has pointed out that some recomend going two sizes up for shackles and swivels. The logic is based on the speciifications, and that at only one size larger the shackle and swivel will be the weakest link in your rig. Do this with care and logic making sure you have shackles that can be used with your chain link size. Extra shackles are not recommended, only use two shackles together when required, as in with a large Dor Mor stem adapting to a chain where one shackle can't couple both dimensions.

Dor Mor Shackle Sizes

If you are using a Dor Mor anchor you will likely need a shackle to adapt the bottom chain shackle to the anchor it self. Dor Mor's have very wide anchor ring. What follows is a chart that describes the size shackle needed based on the anchor you purchased.

Last updated 4:29pm on 11 January 2025