cfauvel
Chief Petty Officer
- Joined
- Aug 16, 2005
- Messages
- 645
we are talking about a 1986 225hp Evinrude on 1986 21' Offshore Yachts (beefed up)
Ok went out today to get a WOT mark and here are some of my numbers using the GPS and Paddle wheel.
I estimated that the boat with 5 people and a dog and full live well, 35 gals of fuel weighs in at 3500 or so lbs.
No trim tabs are on the boat. The motor has a DoelFins= on the antiventilation plate, The boat runs and feels best with the engine trimmed in more than 0 degrees. Trimming out so that the bow lifts and rides the stern pad, does give me more speed, but starts to porpoise alot...just better keeping the bow down to cut through the waves.
I am running a 14.5 x 20" 3 blade raker.
I got the following numbers
RPM Paddle Wheel GPS SOG
3200 23 20
3500 27.33 22
3800 33 25
4000 37 28
4800 45 n/a
5100 50 41
I could not get the magical 5500 RPM, the closest was 5200. At 3500 RPM the boat falls of plane, 3800 RPM is about the slowest I can keep it on plane.
It takes about 7 to 10 seconds to get up on plane.
I want to be able to get up on plane faster, I want to be able to stay on plane at slower speeds and want to hit that magically 5500 rpm. I am not too concerned about top speed since WOT is not the ideal speed for gas and not easy to do in 2-4 foot sea.
I hope I have given all the info I can for people to help me pick out the right 4 blade. I've heard that 4 blades do exactly what I want.
Thanks
Chris
Ok went out today to get a WOT mark and here are some of my numbers using the GPS and Paddle wheel.
I estimated that the boat with 5 people and a dog and full live well, 35 gals of fuel weighs in at 3500 or so lbs.
No trim tabs are on the boat. The motor has a DoelFins= on the antiventilation plate, The boat runs and feels best with the engine trimmed in more than 0 degrees. Trimming out so that the bow lifts and rides the stern pad, does give me more speed, but starts to porpoise alot...just better keeping the bow down to cut through the waves.
I am running a 14.5 x 20" 3 blade raker.
I got the following numbers
RPM Paddle Wheel GPS SOG
3200 23 20
3500 27.33 22
3800 33 25
4000 37 28
4800 45 n/a
5100 50 41
I could not get the magical 5500 RPM, the closest was 5200. At 3500 RPM the boat falls of plane, 3800 RPM is about the slowest I can keep it on plane.
It takes about 7 to 10 seconds to get up on plane.
I want to be able to get up on plane faster, I want to be able to stay on plane at slower speeds and want to hit that magically 5500 rpm. I am not too concerned about top speed since WOT is not the ideal speed for gas and not easy to do in 2-4 foot sea.
I hope I have given all the info I can for people to help me pick out the right 4 blade. I've heard that 4 blades do exactly what I want.
Thanks
Chris