Here is the original post of February 3rd - I run a 17' 1998 Xpress with a 1998, 90 HP Yamaha outboard. The boat gets up on plane fairly easily and fast enough. The only dislike is then when running 3/4 to full throttle (this is on very calm water), and adjusting the electric trim to where I can achieve max rpm and speed the boat starts to porpoise. I have to trim the motor back down to get it to stop porpoising, naturally decreasing the speed and rpm. I have been reading about the pros and cons of installing a hydrofoil stabilizing fin on the cavitation plate of the motor. Some say speed is lost, which doesn't bother me. I can sacrifice 3 or 4 MPH. I would think that being able to run with less boat in the water and without porpoising would be a better ride and use less fuel. I really don't care to mount stabilizers to the rear of my boat. If I could get some suggestions as to whether the installation of a stabilizer on the motor would help my situation, or is it worth it?
thanks
Update: during the past few weeks I raised the motor up on the transom 1 hole. This puts the anti-cavitaion plate approximately 1" above the bottom of the boat. Removed the prop to obtain the following: It is a Ballistic, 3 blade SS, 13-1/2" dia x 17 pitch. Yesterday the lake was as calm as glass with no wind, so the wife and I took the boat out. The results are WOT = 5300 RPM & 44 MPH (speedometer)and no porpoising. Trimmed up until it just starts to porpoise, still WOT = 5500 RPM & 47 MPH. Trimmed back down to obtain smooth ride. (naturally the RPM and Speed dropped to before). Hole shot test = Zero to plane in 5 seconds. Incidentally, in my original post I had stated that I really didn't want to install trim tabs. I have been reading articles about Nauticus Smart Tabs SX and at least have opened my mind to that idea if it takes that to stop the porpoising at WOT, trimmed out.....I'll do it. What do ya'll think?
thanks
Update: during the past few weeks I raised the motor up on the transom 1 hole. This puts the anti-cavitaion plate approximately 1" above the bottom of the boat. Removed the prop to obtain the following: It is a Ballistic, 3 blade SS, 13-1/2" dia x 17 pitch. Yesterday the lake was as calm as glass with no wind, so the wife and I took the boat out. The results are WOT = 5300 RPM & 44 MPH (speedometer)and no porpoising. Trimmed up until it just starts to porpoise, still WOT = 5500 RPM & 47 MPH. Trimmed back down to obtain smooth ride. (naturally the RPM and Speed dropped to before). Hole shot test = Zero to plane in 5 seconds. Incidentally, in my original post I had stated that I really didn't want to install trim tabs. I have been reading articles about Nauticus Smart Tabs SX and at least have opened my mind to that idea if it takes that to stop the porpoising at WOT, trimmed out.....I'll do it. What do ya'll think?
