I was new to bags till last year my new boat has a 150 Yamaha two-stroke and was giving me 2.7 to3+ miles per hour at idle so last spring I purchased 2 18 inch bags for my 22 foot boat and I actually found out they weren’t large enough and went to the Amish outfitters 28 inch bags beefy bags and now I believe I have control of my boat I also found out that lead lengths are critical front and back on bag positioning as well as keeping bag to the sides of the boat versus under the boat there is a definite learning curve but I do believe you can get total speed control with them as well as running higher rpm’s with your two-stroke to eliminate fouling the plugs Sent from my iPhone using Lake Ontario United mobile app