Motion compensators and mooring devices

A motion compensator for underwater use in a mooring of a vessel to an underwater anchorage point, comprising:

• first telescopically acting means for coupling to the anchorage;
• and
• second telescopically acting means for coupling to the vessel;
• said first and second means are also for defining a variable, gas containing volume therebetween such that movement of said first and second means apart from one another expands said volume and is resisted by a restoring force produced by the expansion of the gas containing volume against ambient water pressure at a depth of said underwater use.

A method for mooring a vessel to transfer fluid to or from the vessel, comprising the steps of:

• mooring the vessel by a hose used for said fluid transfer using an underwater motion compensator which has
• (a) a first telescopically acting means for coupling to the anchorage;
• and
• (b) a second telescopically acting means for coupling to the vessel;
• (c) wherein said first and second means are also for defining a variable, gas containing volume therebetween such that movement of said first and second means apart from one another expands said volume and is resisted by a restoring force produced by the expansion of the gas containing volume against ambient water pressure at a depth at which said compensator is underwater;
• and
• transferring fluid to or from said vessel.