SURFACE SUPPORT 



No discussion of undersea work systems can be complete without mention of the 

 surface-support craft and handling systems. Although this subject is extensive enough to 

 be a paper by itself, it is sufficient to state that a stable platform with good position keep- 

 ing is vital to undersea vehicle operations. An important development in type of craft to 

 meet these requirements is the SWATH (small waterplane area twin hulled) ship. The 

 SWATH ship's capabilities are achieved by placing the greater portion of the ship's buoyant 

 volume below the sea surface and supporting the above-surface structure by thin struts 

 which are little affected by wave action. Stability is exceptional both underway and at 

 rest in sea states up to 7. The concept includes full automatic control over pitch, heave, 

 roll, yaw, and sway. The 190-ton Stable Semisubmerged Platform (SSP KAIMALINO, 

 figure 14) was designed and developed at NOSC to satisfy a need for a small, oceangoing 

 work platform which would have the reduced motion, greater deck space, and higher speed 

 of much larger conventional monohulls. The SSP measures 89 feet (27 meters) in length 

 and 45 feet (14 meters) in width. The vessel was designed by NOSC with support from the 

 Pearl Harbor Naval Shipyard; it was constructed at the Coast Guard Yard at Curtis Bay, 

 Maryland. 



Figure 14. SSP KAIMALINO, a SWATH ship. 



The SSP has two submerged, parallel, torpedo-like hulls which support a cross- 

 structure above water by means of four streamlined, vertical, surface-piercing struts. Two 

 controllable canard fins are located near the hull bows, and a full-span stabilizing fin witli 

 controllable flaps is near the hull stern. The fins provide dynamic stability, damping, and 

 control over heave, pitch, and roll. The design configuration of the SSP will permit normal 

 operations in 9- foot (3 meters) waves. With a full fuel complement of 18.8 tons, the SSP 



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