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About Moorings

What is Mooring?

Mooring is the fastening of your watercraft to a fixed object on the lake bed or to a floating object such as an anchor buoy.

Mooring by permanent anchor is the attachment of the watercraft to a float or buoy on the surface, which is itself attached to a permanent anchor at the bottom of the waterway by a rode (a line, cable, or chain).

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Permanent Anchor Moorings

There are four basic types of permanent anchor moorings; dead weight, mushroom, screw in, and triple anchor. These moorings are used instead of temporary anchors because they have considerably more holding power, cause less damage to the marine environment, and are convenient. They are also commonly used to hold dock floats in place.

  • Dead weight moorings are the simplest kind of mooring. They are generally made as a large concrete block with an attached rode and resist movement with sheer weight. They are simple and cheap, and are better suited to rocky bottoms where other mooring systems do not hold well. They are heavy, bulky, and awkward.

    Dead Weight Mooring System

  • Mushroom moorings are the most conventional moorings for mud and silt substrate. They are shaped like an upside down mushroom which can bury itself in these materials quite readily. They have up to ten times the holding power to weight ratio as dead weight moorings, but they’re more expensive and don’t hold well on rocky bottoms.
  • Screw in moorings are shafts with wide blades spiraling around it so that it can be screwed into the substrate. They have a high holding power to weight ratio. Screw in moorings are so small that they are relatively cheap, but a diver is usually needed to install, inspect, and maintain them.
  • Multiple anchor mooring systems use two or more light weight temporary style anchors set in an equilateral arrangement and all chained to a common center from which a conventional rode extends to a mooring buoy. These systems have minimized mass, are easy to deploy, have a high holding power to weight ratio, and are easy to access the anchor components because temporary style anchors are readily available.

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Rode system

The rode system is a line, cable, or chain several times longer than the depth of the water running from the anchor to the mooring buoy, the longer the rode is the shallower the angle of force on the anchor (it has more scope). A shallower scope means more of the force is pulling horizontally so that ploughing into the substrate adds holding power but also increases the swinging circle of each mooring, so lowering the density of any given mooring field. By adding weight to the bottom of the rode, such as the use of a length of heavy chain, the angle of force can be dropped further. Unfortunately, this scrapes up the substrate in a circular area around the anchor. A buoy can be added along the lower portion of rode to hold it off the bottom and avoid this issue.

 

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