Page 122 - The ROV Manual - A User Guide for Remotely Operated Vehicles 2nd edition
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  110 CHAPTER 5 Vehicle Design and Stability
 FIGURE 5.1
Polyurethane fiberglass encased and simple painted foam blocks.
  FIGURE 5.2
Types of syntactic foams.
 Composite tubes with closed end caps have also been used in shallow water applications, as well as a very good PVC material known as Divinycell. This material is blown foam that is quite capable for depths not exceeding 1000 m. It is an open-cell foam and should have a skin added to it for increased protection at depth. It does have some drawbacks, however, as it does not cycle very well. When buoyancy materials are developed and tested, they are subject to 1000 cycles to test depth before they are offered up for sale. Every manufacturer does this and has the data to back up the program.
5.1.2.2 Syntactic foam
For deepwater applications, syntactic foam has been the material of choice. “Syntactic” is a deriva- tive of the Greek word, syntac, which means “to disperse in an orderly arrangement.” Accordingly, syntactic foam is simply an air/microballoon structure encased within a resin body (Figure 5.2). The amount of trapped air within the resin structure will determine the density as well as the dura- bility of the foam at deeper depths.
(Courtesy Trelleborg.)


























































































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