Abstract: A diving sinker has a fin on the top surface of a planing member and a chamber on the bottom of the member. The chamber increases the volume of the diver and, hence, its buoyancy. The chamber is rotatable about the axis of a screw that holds it to the bottom of the planing member so as to move a weighted section in the chamber to gain directional control over the diver as it is being towed through the water from the trolling boat. Space in the chamber that is not occupied by the lead weights is occupied by a rigid foam synthetic resin. The trolling line is fed through the eye at the end of a latching arm and through a slot between two flat surfaces, one of which is movable relative to the other to provide a space or slot between them into which the fishing line may be wedged to secure the diver against sliding on the line.

Abstract: A fishing line release mechanism and a mounting device for trolling at a predetermined depth and releasing the fishing line when a fish strikes the bait. The release mechanism carries a resilient disc which supports the fishing line. The disc is mounted on a hinged member which latches with the release mechanism housing. The release mechanism includes an adjustment screw to control the amount of tension required to trigger the release.

Abstract: A flat plate has means for connecting a fish bait to the rear portion thereof and has a link swingably attached to the front portion thereof with an eye on the end of the link for attachment to a trolling line. An upstanding fin projects from the top of the plate and has a slot located in the forward portion of the fin and extending obliquely rearwardly of the plate for receiving and detachably holding the link in a position which causes the plate to dive when it is drawn through the water. The sides of the slot are flexible and there is an adjustment screw to adjust the amount of force required to detach the link from the slot.