Do It Yourself Mooring

Updated May 7, 2019

Also see

  1. RBC Mooring Standards
  2. Article about moorings by an insurance company
  3. Mooring rigging best practice by Wayne Hamilton, Hamilton Marine
  1. RBC mooring standards are based upon the best practice demonstrated in this video.  Don’t rig a mooring with seeing this video.  Its that good!

    Hamilton Marine on rigging a mooring

  • Do It Yourself Mooring
    How to build a mooring: Building a mooring is something that anyone can do if they have the information, time and a little bit of money.  If you don’t want to do this yourself you have a couple of options.  You can call the Mooring Man and about 1000 dollars later you will have a mooring.  You could wait until one becomes available at the club and then put your name in for it.  Check with the Harbourmaster for cost and availability.

a. Stone: 2000 or 4000 lbs: So if you have decided to do it yourself the first thing that you need is a stone, that is the mooring anchor best for Renforth Cove. This is usually a concrete block that is either 2 by 2 by 4 or 2 by 4 by 4.  If your boat is under 30 feet then the smaller one will do fine.  To get this stone, you can go to a concrete company and ask them to cast one for you. They will only charge you about 25 dollars for this. You should bring them the bottom chain to cast into the block. After it is poured and cured you will have to arrange for a truck to pick it up. The concrete company will load it for you. It is best if this is on a flat bed truck to have it near the back and put a couple of blocks under it so that you can have the truck back down the wharf and then you can easily flip it into the water.

b. Bottom Chain: 22 feet of 1 inch or ¾ chain: The bottom chain is really the key to how the whole mooring system works.  This is more important than the block itself or the size of the top chain.  The job of the bottom chain is to change the direction of “pull” from vertical to horizontal.  When this part of your mooring system is parallel to the bottom for the most part then there is very little chance that your mooring will ever move.  To achieve this, the bottom chain must be heavy, and at least as long as the depth of the water.  Renforth Cove harbour is about 20 feet deep for most of the time, especially for the outer (westerly) moorings in RBC north field.  This chain can be obtained for scrap value at the following sources: the scrap yard at the end of Rothesay Ave, the Coast Guard, or Simpsons down at Five Fathom Hole.  What ever you do, don’t pay full price for this chain!

c. Top Chain 24 feet of 3/8 inch or 1/2 inch proof coil: if the bottom chain is the most important part of the system then the top chain (and shackles) is the weakest link! Pardon the pun!  The role of the top chain is to transfer the weight of the pull of the vessel to the end of the bottom chain.  You will again need a chain that is at least the depth of the water – 24 feet is usually fine for our area.  3/8″ chain is fine for boats under 30 feet, half inch is recommended for bigger vessels.  RBC’s standard is 1/2″ top chain (always err on the side of caution).  The size of the chain is not really critical because of its breaking strength but rather for its additional weight.  You will need two shackles of decreasing size to connect the two chains together.  The pins on the shackles should be “seized” with stainless steel wire.  This is an absolute must!  You can be guaranteed that any shackle left long enough under varying load, will undo itself!  The preferred chain comes from Fales in the McAllister Industrial Park.  This chain American made and is used in the salt and potash industry. It resists corrosion well.

d. Float. Ball or Log:  This is your choice.   Each has its promoters and detractors, traditions, advantages and disadvantages.   Here are thoughts on the matter.

A cedar log that has been drilled, pinned at the bottom and “trained” with a set of training pants will last for years and years with very little maintenance.   For winter preparation all you have to do is slip the headlines off.   The down side is that a log is often harder to spot when picking up your mooring.  These floats can mark your boat if you hit it, and they tend not to get inspected often as it is very difficult to pull the whole log up and actually look at the chain connection.

The inflatable ball is easy to see, inspect and do maintenance on.   If however you don’t get around to removing it in the winter, you only have a slight chance of finding it in the spring.   Between the ice and the snowmobiles they are very susceptible to damage and sinking, or being dragged by the ice flow.   Another reason for the floating ball is that,when you do winterize it, the chain is dropped into the bottom where there is little oxygen, and so the chains tend to last much longer.   As a bonus, you are also forced to do an inspection twice a year simply by servicing it in the spring and fall.

RBC’s standard is an 18″ polyurethane yellow or orange ball.

e. Headlines: Headlines are the connection between your vessel and the mooring ball and top chain.  You should have two of them.   One on the top of the ball (for ball that permit this) where you can see the connection and one (or both) on the chain that goes directly to the mooring.   This second (safety) is a foot or two longer and does not take any load.  It is there in case of failure of the first line.    The lines should be made of nylon and be replaced every three years.   Polypropylene can be used but should never be trusted after two years.  It is extremely susceptible to UV damage and chafe.    Headlines should have chafing gear attached where they go through the chocks on the boat.   The length of the headlines should be between 1.5 and 2 times the distance from the mooring bit on the boat to the surface of the water.     This will look short to you, but it is the safest and most neighborly.   A long headline does nothing at all for the holding power of your mooring.  If you want to increase holding power you must do this with the bottom chain.   A long headline is a hazard to navigation and also takes up excessive room in the mooring field.  Also remember, in areas with tides ,to plan water depth for normal high tide.  Low tide means the total scope of your mooring can increase!

If you use nylon lines then you will need to affix a float at the end of the lines for pickup as nylon sinks.   This gives the added bonus that your headlines are not trailing out in the water causing a hazard to other boats moving through the mooring field.  Yes they are a little more difficult to pick up, but it is good seamanship.

Click this illustration of a typical Renforth Boat Club mooring to enlarge.

Typical Renforth Boat Club Mooring

Typical RBC mooring

When you have your mooring in the water and it is time to put it in position, please contact the Harbourmaster and make arrangements for it to be placed in an approved location.

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