fin shaped skeg 16 is integral with the underside of the housing 12 the skeg 16 has an arcuate frontal region 18 a generally linear rear region 20 and sidewalls 22 as shown in fig2 which is a frontal view of the embodiment of fig1 the sidewalls 22 of the skeg 16 are tapered inwardly the skeg 16 is wide at the housing 12 and is gradually narrower closer to the bottom the bottom edge of the skeg 16 as oriented in fig1 is significantly lower than the lowest edge of the propeller 14 the skeg 16 is typical in shape and size of most skegs the skeg 16 is representative of the type of skeg on which the present invention can be used the present invention may be used on boat motor skegs of various sizes and shapes when the boat motor 10 illustrated in fig1 and 2 strikes an object the skeg 16 typically contacts the object before any other part of the motor 10 the impact may cause part of the skeg 16 to be broken off of the boat motor 10 a different boat motor 24 having part of a skeg broken off is shown in fig3 the entire original skeg is rarely completely broken off so a remaining skeg stub 26 almost always has adequate length to allow mounting of the device a replacement skeg 30 which can be attached to the skeg stub 26 of fig3 is illustrated in fig4 and fig5 the replacement skeg 30 is a generally planar fin shaped structure having a rearwardly angled front edge 31 and inwardly tapered exterior sides 33 the shape of the replacement skeg 30 is similar to the skeg of fig1 the replacement skeg 30 is thick enough to have.