Got the truck back going and took the boat out for some prop trials the past weekend. I tried the 15 1/2 x 21p first and could not get over 5200 rpm and a max speed of 40 MPH. So I jumped to the 17p rev-4 next and was in a better rpm range. The original 17p had been reworked and was more like a 15p and that threw me off to start with. I was thinking I was going to need a 19p or 21p but not the case. I learned that the 17p was best for this combo. The Rev-4 and Mirage Plus both worked well but need to rerun the rev-4 now I have the motor mounted higher up. I had a 48-16314 - 14 1/2 x 17p that was shooting over 6000 rpms and that made me think that the 17p was not enough Pitch. Well after looking at it once it was off there was 3 different markings from prop shops. Im guessing this one was changed to a 15p or reworked to turn higher rpms than a standard 17p. The Mirage plus 48-18278 15 1/2 x 17p done real well. Five people on the boat loaded as I will ever be I could get 5700-5800 rpms. The Rev-4 I could get around 5600 rpms. The top speed on the Mirage was 46 MPH @ 5800 rpm where the Rev-4 17p would only do 43 MPH at 5600 rpms. The Mirage cruse speed around 3800-4000 @ 37-38 MPH was better than the Rev-4 as well. The rev-4 had the full plugs in the vent holes and the Mirage had none in the holes at all. The minimum plane speed was bad with the Mirage. At 3000 rpm it would barely hold plane and it was around 25-27 MPH, but once the vent holes would start venting (10 seconds after holding 3000 rpm) the rpms would go from 3000 to 3300 and it would drop off plane. I thought it would help but it dose not far as plane speed. The vents open do help taking off from a dead stop tho. I would like to try full plugs or small hole vent plugs next to see what that will do. The rev-4 was tested the first day and the motor was way low. I raised it up for the second day 3" higher when I done the Mirage 17p testing so I want to retest the rev-4 to see what it will do up higher. With the motor low it would do well and hold plane at 27 mph at 3000 rpm easily where the mirage would not. Had a lot less bow rise with the rev-4 and better stern lift. The cruse was good at 3800-4000 rpm @ 32 MPH and it had little slip and was a fast smooth accelerating prop. On the way back down the river after we stopped to eat it was ruff white caps at 10 foot intervals maybe 3-4 footers running with a following sea with the wind to my back and it held the boat on plane well and did not slip at all even when we were up out of the water some. She did not do well under 30 MPH but above it she stayed on top and skipped across the caps and did not beat at all and that stopped the digging from the following sea. Even below 30 mph she did dig a little but even then the spray rails worked well and all the water sprayed outward and not much spray came back on us. It may in a cross wind but done well this day. I have not tried the 48-13700 151/4 x 19p Mirage yet and may do so now with the motor raised and with a lite load just to see but I will do the same run with 5 head with the Rev-4 17p with the motor up just to see my difference the 3" raise made. I know they are more of a semi surface prop so it should be better. The motor needs to go up a few more holes but it is maxed out now where it is so I will keep that in mind when I move it to the scepter 20'. I'm sure it will take a different prop on thee 20'vs the 27' but it has been fun running the race hull some and gave me a chance to do it before I start tearing it apart for the redo. We even caught some fish too. I got a 20" drum and a 14" flounder Sunday evening. I will probably run it once more just to take it out one last time and see what the differences make and then I will Post a final chart of all the prop performances and make it a little more readable than this.
Few Pics of the trip out:
