Kim and Mevciev 



MOTIONS RESPONSE OF A RELATED SERIES 

 OF THREE AND FOUR FLOAT PLATFORMS 



BACKGROUND 



In the early 1960's a substantial program of research and de- 

 sign analyses was undertaken on the concept of using slender vertical 

 floats to support water-based aircraft, thus providing a comfortable 

 and stable environment for crew and equipment. This work was sup- 

 ported by the United States Naval Air Systems Command under the 

 cognizance of E.H. Handler, whose review article on "Tilt and Vertic- 

 al Float Aircraft for Open Ocean Operations" describes the progress 

 of this concept up to 1966. Two early studies of particular significance 

 established the validity of the concept. In one of these studies two 

 PBM seaplanes [2] were tested in five-to-eight-foot high waves. One 

 of these craft was supported avobe the water surface by vertical floats 

 and was found to be quite comfortable while the crew of the convention- 

 al PBM soon became uncomfortable. The other investigation involved 

 a one-man helicopter which was equipped with tiltable floats L^J and 

 tested in heavy, choppy waves, reacting with slow and gentle motions. 

 Earlier model tests of this vehicle at Davidson Laboratory [4] led to 

 the introduction of horizontal plates at the lower end of the vertical 

 floats, which are found to be a vital feature in the effective employ- 

 ment of this concept. 



In order to provide systematic design information for the dy- 

 namic performance in waves of these types of craft, results of a series 

 of vertical float configurations which have been model tested in ir- 

 regular waves to determine their response characteristics have been 

 described by Mercier [5J . Variations in the series include number of 

 floats, float spacing and slenderness, size of damping plate and meta- 

 centric height, and heading of the vehicle relative to the waves. The 

 information developed may also be useful for other types of craft, 

 such as work platforms, research and range -tracking platforms, oil- 

 drilling rigs and possibly buoys, which can be configured with vertic- 

 al floats. 



Float supported platforms may be envisioned with any number 



* Superior numbers in text matter refer to similarly numbered 

 references listed at the end of this paper. 



796 



