Join Date: Oct 2009
Location: Gloucester, MA
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Reef, you will not be able to install the mooring by simply swimming as you won't be able to exert enough force if the bottom is any good. You either need good traction on the bottom (note- I have personally never installed one in deep enough water that I have had to suit up and dive) or you need to have a boat very firmly anchored in place to work from. If you have a way to extend the shaft of the helix so that it is long enough to be reached from above the water's surface, this works decently well but you do need to spend some time getting the anchor lines adjusted right (or you need to rent a spud barge). Anytime you do this, you should make sure that the soil is appropriate for the anchor type.
Flybyknight, putting 3 helix anchors at 120 degrees apart is very different than putting 3 danforths or similar in the same arrangement. In this arrangement, each anchor has to be able to independently take all of the load from the boat (imagine 1 anchor being directly upwind, the other two won't do anything). A helix makes a great boat anchor not only because of its holding power but because it doesn't need to reset or rotate if the direction of pull changes. If you take the examples of danforths, 3 anchors is necessary so that the anchors always see a relatively straight line pull. There is way more to the 3 anchor arrangement than most people realize, the lengths of chain are very critical to really minimize the load. The arrangement does work quite well but a lot of people install them improperly because they don't understand the important of the geometry.
It is possible to rig up a load sharing arrangement between multiple anchor points so that they will have relatively equal loading independent of wind direction but this is not standard to my knowledge. The problem is that you need to allow for moving parts which tend not to work well over long periods of time underwater. The way that most systems are setup, in most wind directions, one anchor will be doing all of the work and the other one will simply be there for backup.