Permanent Anchor Mooring
    There are three basic types of permanent anchor moorings; dead weight, mushroom, and helix . 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.

Example: US Virgin Islands, a vast number of public moorings are set out in popular areas where boats can moor.
This is to avoid the massive damage that would be caused by many vessels anchoring in close proximity.

    Dead weight moorings are the simplest kind of mooring. They are generally made as a large concrete
    block with a rode attached which resists movement with sheer weight; and, to a small degree, by settling
    into the substrate. The advantages are that such moorings are simple and cheap. A dead weight mooring
    that drags in a storm still holds well in its new position. Such moorings are better suited to rocky bottoms
    where other mooring systems do not hold well. The disadvantages are that they are heavy, bulky, and
    awkward.
    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. The advantage is that
    it has up to ten times the holding power to weight ratio as compared to a dead weight mooring. The
    disadvantage is that they're more expensive than dead weight moorings, don't hold well on rocky or pebbly
    substrates, and they take time to settle in before reaching full holding capacity.
    Pyramid mooring anchors are designed to rapidly penetrate the sea floor due to their sharp pointed
    sides and compact size. They have be tested and are said to have a range of 3 to 10 times it's dry weight
    in holding power.  The holding power increases as the anchor penetrates the sea floor.  This is due to their
    unique pyramid shape and large surface area which increases the suction effect the deeper it sets.
    Helix moorings are a modern method. The screw in mooring is a shaft with wide blades spiraling around it
    so that it can be screwed into the substrate. The advantages are an extreme high holding power to weight
    ratio. An additional consideration is size. Helix moorings create a small footprint in the sea bed floor. In
    addition, once in place, they do not drag or move as dead weight or mushroom moorings tend to do. The
    advantages are minimized mass, high holding power to weight ratio, and less wear to the gear.

       
Helix Mooring Benefits:    Holding power pull test

                                                   
Vineyard Haven, Pull Test Results

                                                 
Mooring Type Bottom Condition Breakout Force

                                                 350-lb. Mushroom   5 ft. deep in mud   2,000 lb.
                                                  500-lb. Mushroom   in sand bottom   1,700 lb.
                                                 3,000-lb. Concrete USCG block   set in mud   2,100 lb.
                                                  6,000 lb. cement block   on sand bottom   3,200 lb.
                                                          8/10 Helix   soft clay mud   20,800+ lb.

                                     We use 8-10-12 helixes -- which provide even greater holding strength
 Helix moorings