lying at the base or hanging from various 

 portions of the array. Rigging and handling 

 lines may part under heavy strain resulting 

 in a large ball of loops, snarls, etc. These 

 lines, which are generally not shovi^n in the 

 array or buoy schematic, can be more haz- 

 ardous than the hardware itself. 



Surface Traffic: The primary danger to the 

 submersible from surface traffic is the possi- 

 bility of surfacing under or in the path of 

 transiting vessels, and, to a lesser degree, 

 being snagged by a fishing vessel. Most sub- 

 mersibles lack the control and the sensors 

 necessary to stop ascent and assure that no 

 surface traffic is present. Although the sub- 

 mersible's support ship may be displaying 

 the proper signals to denote subsurface op- 

 erations, commercial or pleasure craft may 

 and often do ignore them. 



Subsurface Traffic: The possibility of collision 

 with a fleet-type submarine in the open sea 

 is small. There are, however, areas of the 

 ocean clearly marked on navigation charts 

 as submarine transiting lanes. In some in- 

 stances clearance to operate in these lanes 

 and various ranges can be obtained by prior 

 arrangement and appropriate charts along 

 with supporting data may be available prior 

 to an operation. Although the operator is 

 under no legal requirements to coordinate 

 his efforts with the Navy, to ignore such 

 lanes and operating areas can place the sub- 

 mersible in danger of collision. 



Explosive Ordnance: Millions of tons of explo- 

 sive ordnance have accumulated on the floor 

 of the world's oceans and seas, particularly 

 over the last century. Explosive projectiles, 

 sea mines, torpedoes, depth charges and 

 bombs, hedgehogs and aerial bombs repre- 

 sent a threat to submersibles. Some may 

 detonate only by contact, but others may be 

 detonated magnetically or by pressure 

 changes. The submersible operator will ob- 

 viously avoid ammunition dumping sites, but 

 an inestimable amount of ordnance litters 

 the ocean floor at all depths and in all loca- 

 tions. The nature of this hazard is discussed 

 in detail in reference (4). The explosive 

 threat is not the only aspect of such ord- 

 nance; moored mines have employed moor- 

 ing cables ranging in length from less than 

 100 feet to 5,000 feet. The cable is small in 



diameter and is connected to an anchor 

 which, depending upon the mine, may range 

 in weight from about 300 pounds to 1,500 

 pounds (in air) and is connected at the other 

 end to a mine case which may range in 

 weight from 50 pounds to 1,000 pounds (in 

 air). Snagging or becoming entangled in this 

 cable could represent a serious hazard. In 

 some areas the density of these cables and 

 anchors is quite high. For instance, in the 

 zone running between the Orkney Islands 

 and the coast of Norway some 71,000 cables 

 and anchors litter the bottom. 



Miscellaneous: The effects of radioactive 

 wastes and corrosive chemicals on a sub- 

 mersible may not be immediate, but the long 

 term effects of investigating such dumping 

 grounds could be hazardous, not only to the 

 vehicle itself, but to the surface support crew 

 as well. 



Abandoned, lost and discarded junk of all 

 descriptions litters the sea floor, especially in 

 areas of high surface traffic. In most cases, 

 information is unattainable concerning such 

 debris and the pilot is left to his own discre- 

 tion. Little can be said concerning where 

 discarded hardware, cables, and lines will be 

 encountered except that historically high 

 density ship traffic areas are the most likely 

 areas. Harbors, roadsteads and channels — 

 contrary to rules and regulations — are gen- 

 erally littered with all types of debris. Lim- 

 ited visibility generally prevails in such 

 areas, and the practice of making shallow 

 test dives in a harbor while the surface ship 

 is conveniently tied up may lead to unfore- 

 seen consequences. Fortunately, these areas 

 are generally shallow and therefore permit 

 diver assistance in the event of an 

 emergency. 



From the foregoing list of potential haz- 

 ards, it would appear that diving is a danger- 

 ous pastime; it is. In spite of the cute names 

 given to some vehicles, there is nothing cute 

 about cold, pressure, asphyxiation or drown- 

 ing, and the high safety record in submersibles 

 reflects the fact that serious, contemplative 

 consideration of such hazards has preceded 

 the thousands of successful dives. Such con- 

 sideration follows two fundamental planes: 

 Preventing the emergency, and responding 

 to it. Certification and classification are the 

 frontline defenders for prevention. 



635 



