What a difference an inch makes...in props
Just got back from an incredible weekend in Seward. I took my new 21' North River Seahawk w/ 150 Yamaha out to test the new prop set up. I went from a 13-3/4 x 15 (that's what they put on my motor?!) to a new aluminum 14-1/2 x 17 three blade prop. What an incredible difference an inch or two makes! At WOT I was getting about 43 MPH at 5800 RPM. I liked the 3-blade prop so much that I didn't even try the 4-blade that my dealer gave me to try out. Was getting about 34-ish MPH at 4000 RPM and was able to stay up on step at lower RPM's (3000-3500). I run my boat fully loaded (heavy most of the time). Total weight between 3600 and 4000 lbs.
Oh yea - caught a few fish. Trolling for kings we caught 3 halibut inside the bay. Went outside to Johnstone and got into the grey cod and flounder but I did manage to catch a nice yelloweye. We ate most of him that night. I didn't know yelloweye tasted that good. Other than the wind blowing during the day the weather was great the whole weekend!
Life is good...
My new prop
I just went out of whittier yesterday with my new prop on my Weldcraft 220 Ocean king and Yamaha 150. I went from a 13 1/4 X 17 stainless Solas 33 MPH WOT @ 6000 RPM's to a 15 1/4 x 15 Yamaha steel prop as listed on yamahas performance page. I got 37 MPH WOT @ 5600 RPM's it gets on step much faster too. I had 4 people 90 gallons fuel. Cruised 30 MPH at 4800 RPM's. I wish I knew more about diameter effect. Why would you want to run the smaller props? I understand the pitch but I dropped a pitch and got more speed with larger diameter. Considering a 15 1/4 X 17 but I am very pleased with this improved performance Three Humpbacks feeding in passgage canal last three days bubble netting small fish. Saw a few chums jumping out around ester Island.
Four Blade Stainless
Went to Deep Creek the last few days and tried out the four blade ss prop. Even better performance. 5600 rpm and 44 MPH WOT. Launches out of the hole. Troll speed 1.5to 2 MPH. I'll keep that one on the motor and keep the 3blade alum for a spare.
Fish Count - 8 halibut / 0 kings