If the payload is not to be separated from the guide frame and the 

 payload is bulky, it is advisable to weld the guide cone directly onto 

 the side of the payload. 



To avoid hydrodynsmic instability during descent or ascent, the 

 whole payload package and the guide frame should be as symmetrical as 

 possible. Vertical vanes can be added to the payload package to stabilize 

 possible rotational motion. 



For each guideline there should be one guide cone with both upper 

 and lower skirts afixed to the guide frame. The guide cone should be 

 designed to quickly open and close for the enclosing and releasing of 

 the guideline. A quickly operated latch is needed for this purpose. 

 The tube section of the guide cone should be reinforced with collars, and 

 the latch should be capable of transferring the circumferential load in 

 the tubes. The internal surface of the tube should be clear and smooth 

 to avoid abrasion of the guideline. The diameter of the tube depends on 

 the size of the guideline or the diameter of the guide post. The inner 

 diameter of the tube should be larger than the outer diameter of the 

 guide post for a smooth fit. Sliding of the tube over ordinary wire 

 rope can create abrasion grooves on the tube wall. A set of roller 

 bearings installed in the guide cone can effectively prevent abrasive 

 wear to the tube and to the guideline. Low friction plastic should be 

 considered as an alternative to roller bearings to reduce abrasive wear 

 on synthetic lines. The tube should be short enough to reduce the 

 friction, but long enough to obtain righting moment against tilting of 

 the guide frame during deployment. 



Operation of the Guideline System 



Two basic rules must be followed in order to ensure a guideline 

 system free of entanglements: 



1 . Reduce or compensate the surface motion of the platform so 

 that at no time shall the tension in either the guideline or the lift 

 line be zero. 



2. Provide every possible means to release the in-line torque in 

 both the lift line and the guideline. 



Those factors that enable the fulfillment of these basic rules 

 are discussed in the following sections. 



Surface Platform. The first step of the guideline operation is to 

 position the surface ship over the proposed anchor site. The position 

 of the ship is monitored by a navigational system, such as Lorac. In 

 shallow water the ship can be moored to maintain station. However, in 

 deep water, the ship must be capable of maintaining station by means of 

 a dynamic positioning system. The maximum drift of the ship should not 

 be more than 10% of the working depth. For more precise measurement of 

 the anchor landing position, an underwater acoustic transducer system 

 can be used. For instance, a three-transponder system was used in the 

 SEACON I project [6] . 



14 



