fig1 illustrates the submerged single point mooring apparatus of the invention in which a vessel 10 is shown moored to a mooring system shown generally at 20 . the vessel is shown in two positions . the first shows the vessel floating under conditions of a low low water ( llw ) of the body of water and moderate forces acting on the vessel tending to force the vessel away from the mooring . the second , at a high high water condition ( hhw ) is also illustrated under conditions tending to force the vessel away from the mooring . under conditions of a fully loaded vessel at llw , the yoke suspension means 15 is selected such that the yoke 30 securing the vessel 10 to a mooring base 40 is substantially horizontal and parallel to the floor of the body of water 5 . a triaxial articulation means 50 allows the yoke 30 to move in yaw , pitch and roll in response to such motions on the ship 10 with respect to mooring base 40 . yoke suspension means 15 connects the outer ends of arms 31 and 32 of yoke 30 to mooring brackets 12 on the vessel . the yoke suspension means 15 may advantageously be heavy chains or multiple wire rope tendons or alternatively may be a rigid metallic shaft with swivel means 15a for axial swiveling of one end relative to the other . the yoke suspension means 15 in combination with universal joints 33 and 34 connected to the vessel and to an outer end of a yoke arm advantageously allow a strain and wear free three degree of freedom rotation between the yoke suspension means 15 and the vessel 10 or the outer ends of yoke 30 . under conditions of an empty vessel at hhw , the yoke 30 is inclined upwardly with respect to the floor of the body of water 5 . fig2 shows a plan view of the submerged single point mooring apparatus . the triaxial articulation means shown generally at 50 consist of a turntable structure 60 mounted on the mooring base 40 and a coupling means 70 connecting the turntable 60 to the yoke 30 . the turntable 60 is adapted for rotation about a vertical axis 61 . a first pin 62 is mounted in the turntable structure 60 coaxial with pitch axis 62a and rotatably connects the coupling means 70 to the turntable structure 60 . a second pin 72 is integral with the coupling means 70 and is oriented orthogonally to the first pin 62 . the apex end of yoke 30 is free to rotate about pin 72 . thus the yoke 30 is free to yaw , pitch and roll about the three mutually orthogonal axis 61 , 62a and 72a while securely attached to the submerged mooring base . the outer ends of yoke 30 contain weight holding means 80 for securing heavy weights 81 which may be high density concrete blocks and the like sufficient to provide an adequate position restoring force to the vessel via yoke suspension means 15 as the suspension pendants are inclined as a result of wind , wave and current forces 11 acting on the moored vessel . the weighted yoke suspension means 15 , universal joints 33 and 34 and yoke 30 in combination with triaxial articulation means 50 thus provide a resilient position restoring force to the vessel and simultaneously allows the moored vessel to surge , heave , sway , pitch , yaw and roll in response to wind , wave and current forces . flexible conveying hoses 90 and 91 are provided for connection from either side of the vessel to piping along the yoke and to a product swivel 95 mounted on the triaxial articulation providing a conduit to a submarine pipeline 96 . alternatively , rigid piping with fluid transfer swivel articulations may be provided . fig3 shows a detailed view of yoke suspension means 15 and universal joints 33 and 34 in the embodiment where the suspension means are multiple wire rope tendons . only three tendons are shown while in actuality there may be several rows of tendons with two or more tendons in each row . this embodiment of suspension means 15 will absorb twisting of the suspension tendons ( due to yawing motions of the yoke and the vessel ) without need for special axial swiveling means . an important feature of this embodiment of suspension means 15 is the arrangement provided for equalizing the loads on the individual tendons . the wire rope tendons are attached at one end , preferably at the upper universal joint 33 , to threaded rods 35 with adjustment nuts 36 . this arrangement permits adjustment of the tension in each individual tendon and also easy replacement of single tendons while the yoke weight remains suspended on the remaining tendons . fig4 shows the preferred means of equalizing the tension of the tendons . each of the individual tendons in a group of multiple tendons will be tensioned simultaneously by standard hydraulic bolt tensioners 37 . the hydraulic tensioner grips the outer end of the threaded rods 35 and pulls the tendons 15 to the required tension . the stop nuts 36 are then seated tight while the hydraulic tension is still effective , after which the hydraulic pressure is released and the hydraulic tensioners 37 removed . fig5 illustrates that the suspending elements may be single or multiple chains . all hydraulic tensioners 37 will be in one group of tendons and be pressurized from a common hydraulic pressure line 38 , thus insuring equal tension in all tendons in the group regardless of differences in initial length or different stretch ratios for individual tendons . thus there has been provided a single point mooring system according to the invention in which the mooring base and yoke are preferably submerged under extreme conditions of either low low water and heavy loading of the vessel or high high water and empty loading of the vessel . such a completely submerged mooring system provides a means for mooring a vessel to an offshore pipeline or the like while substantially protecting the mooring and the yoke from ice flows and heavy sea conditions . the system provides a resilient restoring mooring force to the vessel in response to forces tending to force the vessel away from the mooring and provides a means for connecting the vessel to a fixed mooring base while allowing for surge , sway , heave , yaw , pitch and roll motions of the vessel . various modifications and alterations in the described structures will be apparent to those skilled in the art of the foregoing description which does not depart from the spirit of the invention . for this reason , these changes are desired to be included in the appended claims . the appended claims recite the only limitations to the present invention and the descriptive manner which is employed for setting forth the embodiments and is to be interpreted as illustrative and not limitative .