A Bimini knot tying assist device having a line twister for twisting together in a pre-designed manner portions of a standing line section and a tag line section of a Bimini knot to form a twist or spiral segment, a movable compression element for axially, proximally, linearly compressing the segment and holding it at a predetermined axial distance from the twister, a slide structure for mounting the twister on an elongated support for allowing limited axial movement therealong of the twister during formation of the knot by an operator wherein the operator applies a forward pulling force on the line sections, and a retraction component connected to the support and to the twister for applying a retraction force to the twister against the forward pulling force applied by an operator to the line sections.