[Posted on March 23rd, 2015 by Bill Stewart]
Single point moorings can be used as a station within the ocean for ships and oil rigs as a halfway point between where they need to be and land. It can help to save time and costs. The mooring is essentially a floating platform and when choosing to work with or build such a system, there are various things to explore.
There are several aspects that go into single point moorings. This includes the anchor that is at the bottom of the ocean, the mooring line, and the connectors. The mooring line is ultimately what gets connected to the anchor and then goes up to the floating structure at the top of the water’s surface. The material of this line can vary from wire to chain to synthetic fiber rope. What is actually used will depend upon an array of environmental factors.
The right material needs to be used for the situation, otherwise it is possible for the line to break, causing the mooring to free float without being tethered down.
The entire system of a mooring relies on the strength of the anchor or anchors at the ocean floor. Analysis of soil composition needs to be made so the anchors are properly seated into the soil. There are such types of anchors as vertical load, suction, and drag embedment that can be used. If the wrong anchor is used, it can drag across the ocean floor, causing the mooring to sway and relocate.
The Actual System
There are several systems that can be used with a mooring. The ASCE will often speak about the different systems based upon the type of water that is being used. Single point moorings are ones that include a buoy, anchoring elements, mooring, and a product transfer system. These are most commonly used within the oil drilling industry, but it can be used for other industries as well. It’s important to understand that this is one of the many systems out there. Others include catenary, taut leg, dynamic positioning, and spread.
Some consideration has to be made as to where the mooring will be positioned. It cannot be placed simply anywhere in the ocean. There needs to be a plan as to where it goes based upon where the work locations are and where the land is. Further analysis of the ocean floor conditions may also need to be made.
Understanding the environmental factors are ultimately the most critical part of looking at a mooring. Some of the various factors that need to be considered include ocean waves, currents, and wind.
Analysis has to include the various environmental conditions of a project to determine how the mooring should be built and using what materials. At Stewart Technology Associates, we offer various analytical reports that can be useful.