text: fig1 shows a chain sheave 1 which rotates in the clockwise direction during pay - out of a mooring or anchoring line consisting of a rope r and a chain c interconnected by means of a coupling link 3 which is of generally spherical configuration and may e . g . be of the type described in the copending application ser . no . 559 , 774 of krogstad and odegard , filed on mar . 19 , 1973 , now pat . no . 3 , 977 , 181 . as will be seen , the coupling link has been landed correctly in a pocket 6 of the chain sheave owing to the fact that the chain c is oriented in the chain sheave in such a manner that the chain link 4 linked to the coupling link 3 is in vertical position , every second one of the following chain links 9 , 9 &# 39 ; being likewise in vertical position . if the chain had been turned 90 ° with the links 4 , 9 , 9 &# 39 ; horizontal and present in pockets , the coupling link 3 would have landed on the top of two opposed teeth 7 , 7 &# 39 ;. in that case the deviation of the rope r from the longitudinal axis of the coupling link would have been beyond the permissible limits , so that the rope would be subjected to friction and bending stresses . fig2 is a section through the sheave showing its bottom groove 12 , a pocket 6 and a pair of opposed teeth 7 , 7 &# 39 ;. fig3 and 4 illustrate the function of the arrangement according to the invention , both illustrating the same situation during haul - in as viewed from different angles . fig3 shows the chain sheave rotating in the counter - clockwise direction , the coupling link 3 having been received in a pocket when it first entered the chain sheave , which was at that time not driven , since at that stage haul - in was performed by a separate rope winch . however , at the time of engagement of the angular position of the coupling link about its longitudinal axis was not under control , and in the situation illustrated , the adjacent chain link 4 and links number three 9 and number five 9 &# 39 ; have landed in horizontal position on the top of teeth 7 , 7 &# 39 ; as illustrated . if all the links had been common links , the chain would probably have synchronized itself with the sheave after some time without twisting , and it would then have been so displaced relative to the circumference of the sheave , that upon rotation of the chain sheave in the opposite direction during pay - out , the first link 4 would land in horizontal position in a pocket , and the coupling link 3 would therefore land on top of a pair of teeth 7 , 7 &# 39 ;. fig3 and 4 illustrate how the first asymmetric link 9 , when landing in horizontal position , immediately tends , owing to its special configuration , to rotate towards vertical position , and the next following asymmetric link 9 &# 39 ; will complete the twisting , so that the next link 11 is approximately horizontal and located in a pocket . when the sheave subsequently rotates the other way , the asymmetric links 9 , 9 &# 39 ; will be vertical , and the correctly synchronized situation as illustrated in fig1 will exist . in order to improve the engagement of the asymmetric links 9 , 9 &# 39 ; with the teeth for causing rotation of these links , the latter may advantageously have a greater length than the common links of the chain , the length of the common type adjacent and intervening links 4 , 4 &# 39 ;, 10 and 11 being then chosen correspondingly smaller than that of a common link so as to make the total length of the string of links , 4 , 4 &# 39 ;, 9 , 10 , 9 &# 39 ;, 11 approximately equal to that of a string of the same number of common links . fig5 - 7 show the configuration of an asymmetric chain link according to one embodiment of the invention . one longitudinal side 14 is concave , and the other longitudinal side 15 is more convex than that of a common link . the convex portion of the link has a somewhat greater thickness than that of a common link . the link is in the form of a solid body having holes 16 , 16 &# 39 ; which are somewhat larger than the rounded stock at the ends of a common link . disregarding the convex portion , the diameter of curvature of the surface of engagement of the link 17 , 17 &# 39 ; is approximately the same as a common link .