acquainted with the problems of mothbalied ships, are well aware 

 of these troublesome organisms. These things happen and I urge 

 you to exercise all kinds of caution in this regard. Plastics, too, 

 often fail due to the presence of sulfur in the bottom environment. 

 Many of the sediments have a high sulfur content, and many of the 

 plastics are adversely affected under these circumstances. 



We have negligible data on the combination of high hydrostatic 

 pressures and marine organisms. Yet we know this is a very potent 

 combination. We need more work here. Accelerating such environ- 

 mental tests is difficult. For instance, plastic changes its proper- 

 ties under pressure. Can we accelerate these effects by simply 

 increasing the pressure still further? Under this greater pressure 

 it is not the same kind of material that it was before. 



Also, you in industry, and the Navy, are becoming cautiously 

 aware that synthetic salt spray tests simply do not represent the 

 normal environnnent. 



I am sure of only two safe materials in the plastics or near- 

 plastics: gutta-percha and polyethylene. The first is very old, 

 selected by Lord Kelvin, who did better than he may have realized 

 in selecting it for the insulation of the marine telegraph cable. This 

 has stood up over many, many years. The other, a much more 

 modern material, polyethylene, has been used a much shorter time 

 but shows promise. However, it would be very dangerous to assume 

 that because polyethylene stands the environment, that polypropylene 

 will also. Maybe it will, but I do know that there could be some lit- 

 tle marine organism sitting around that would just love to work on 

 this molecular modification. This is something we may learn more 

 about, but we must be very careful in extrapolating our experience. 



You have heard references made to telemetry. The oceanog- 

 rapher must collect data over a very large area. Radio, of .course, 

 appears to be the answer. But here again the oceanographer runs 

 into problems, partly because the space in the electromagnetic 

 spectrum is already overcrowded, and interference is tremendous, 

 particularly in that part of the spectrxim he prefers, mainly the 

 high frequency bands. These wave lengths are both the most 

 crowded and the most advantageous. The VHF and UHF portions 

 of the spectrum are line-of-sight at ordinary power. Thus, two 

 alternatives are being proposed: First, the use of aircraft for 

 highflying interrogation and recording devices may sound relatively 



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