I just installed the new rockguard on my 35 SD. The motor is on a 24 X 42 Duracraft with plywood floor and I usually carry at least 20 gallons of gas because that gives me 140 to 160 miles range. I took 2 people fishing last weekend in the Chatanika river outside of Fairbanks. It has about a mile of rock and gravel below the landing that is 5 to 12 inches deep with several boat eating rocks that are aluminum coated. I touched the skeg and guard about 4 times going downstream through the rocks and 3 times coming out. The prop showed no hits. My downstream speed was 24 mph and upstream was 20 mph, which is almost identical to the speeds I was getting before installing the rock guard. Out in the mud and weeds of Minto Flats it ran like a typical GD with no weed build-up or problems in the mud. I didn't like the longtail rock guard but this new one for the SD is a real winner if you ever run in rocks and gravel.