Pontooners are often faced with the lowest water levels of the season about now each year, when close encounters with prop-demolishing structure peak during the “Dog Days” of summer.
For any boater whose lower unit has hit a rock while underway – at any speed — there is no doubt about what has been struck. I know from first-hand experience that even the submerged stumps of oak trees offer a little “give” when blades of aluminum or steel cleave into the hardest wood. That’s not the case with granite, limestone or even sandstone. Depending upon how fast the boat was going and the point of impact, the damage from a rocky encounter can run the gamut from a simple nick in an aluminum blade to the loss of the entire lower unit.
You will eventually “bottom out” in your boating career. Dents and bent blades sometimes can be temporarily “fixed” on the spot. Using vice-grips or channel lock pliers, aluminum blades can be bent back to their original position, or at least close enough to get the boat underway without undue vibration. That’s not the case with stainless steel, which is too strong to easily bend, but I’ve seen it tried.
I have a fishing guide friend who dips the face of each of his props in fresh concrete to make an impression before installing them on his outboards. When he hits something substantial enough to bend his aluminum blades, he removes the misshapen prop, places it in its mold, and hammers it back into shape using the rock-hard impression as a guide.
However, vibration from props that have been bent out of factory form can cause damage to lower unit bearings and seals, so no matter how close you think your prop is to “original” after impact with anything, have it checked by a professional.
Of course, it’s best to avoid close encounters of the hard kind in the first place, by avoiding rocky areas altogether, giving gently sloping shorelines a wide berth, studying charts and watching the depth finder, and tilting up the outboard when crossing shallow water.
If your ‘tooning frequently takes you into waters where collisions with rocks, stumps and other obstacles are commonplace and collisions virtually unavoidable, you might want to consider some added protection for the working end of your engine. Keep in mind that most of the commercially available prop protectors, because they do create drag and can affect engine performance, are intended for low-speed use only. Which is the pace you should be proceeding in shallow, obstacle-infested waters anyway!
FOR MORE INFORMATION:
ClackaCraft Prop-Guard: 503-655-9532; clackacraft.com
Comprehensive Listing of Prop Guards: floridaconservation.org/psm/prop/propguide.htm