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Prop selection- 97 21' Outrage 250 EFI Merc
|Author||Topic: Prop selection- 97 21' Outrage 250 EFI Merc|
posted 03-11-2004 06:14 PM ET (US)
I am repowering my 1997 21 Outrage with a 2003 Mercury 250 EFI. The motor I am replacing is a 1997 Mercury 225 carb. It has a 19P Laser II stainless that I can use but I have been told that the LaserII may not be the best design for the boat- made for lighter/smaller boat applications. Besides that, the size may not work out.
I used the Mercury prop selector and I am getting vey different results (performance, prop type and pitch) based on the "boat type" I choose-"fiberglass fishing" or "offshore fishing".
Weight estimated based on:
Dry Boat Weight: 2500
BoatType: Fiberglass Fishing
I want to go with a stainless.
I know the site is just a general guide. My dealer will work with me on propping the boat on the water with an appropriate prop- just wanted to get the expert's opinions.
I know this is long but I wanted to throw all the facts out there.
Thanks in advance!
posted 03-11-2004 08:24 PM ET (US)
Looking at your results I have seen something that I didn't notice before: the Mercury propeller calculator must allot a particular "hull factor" value based on the TYPE of boat you indicate. In the results above when the weight is held constant and the boat type varied, the "offshore" boat goes slower than the "fishing" boat. This probably reflects an estimation of the hull factor in the speed calculation (which is based on horsepower, weight, and hull factor). An "offshore" boat would probably be considered to have a deep-vee hull and thus a lower hull factor index than a "fishing" boat, which would be a moderate vee-bottom.
My simplistic understanding of these various Mercury propeller lines is limited to relationships like that between the Black Max and the Vengeance. I see those as similar designs just made in different materials. The Laser II has more rake and cup to the blades. If you have a boat capable of doing 45-MPH or more I am sure the Laser II would be a good propeller.
I am certain others can comment with much greater authority on this topic and I hope they do.
posted 03-11-2004 09:11 PM ET (US)
Jim I think your comment on the "offshore" and "fishing" boat classification is right on the money. I would tend to lean toward the "offshore" classification as appropriate for this boat. I have only owned the boat since the end of October 2003 and put about 15 hours on it. With the LaserII top speed with light load (1/4 tank fuel, 2 people, light wind, calm water) was about 45 mph per gps at 5200 max rpm. She was sluggish out of the hole but performed well on plane. Handling though in a bit of current and chop seemed to be a bit sloppy- I did not feel like I had great control of the boat.
I think you are also on the money regarding the prop.
From the Mercury website:
For outboards 75 hp and up and Alpha Sterndrives 3.0L - 5.7L
Maximum top speed is not my top priority- handling in seas and midrange performance is. I am going to use the boat a majority of the time for inshore fishing- a couple people on the boat, full fuel, ice and fishing gear (plus a bunch of fish!) is going to add a bit of weight. Don't get me wrong I like a fast boat as much as the next guy but as you all know this is not designed to be a high speed boat.
Thanks again for your interest and your comments.
posted 03-17-2004 11:59 AM ET (US)
I owned an OR 21 with a '98 Yam 225 EFI. No t-top, it ran 47 mph at 5500rpm trimmed, two adults, 2/3 a bag of gas. Would do 50 w/ light fuel load and one person aboard. Would jump on plane in about 2 seconds without going to full throttle, and it averaged about 3.2-3.3 mpg anywhere between 3000-4000 rpm (25-35 mph). Prop was 15.5x17 Mirage Plus. I have M+ props on newer OR 23 w/ twin 150s and have seen similar benefits in hole shot and mid-range performance.
posted 03-17-2004 04:13 PM ET (US)
Take a look under the PERFORMANCE forum for the following - last updated (as of today anyway) on 2-6-04 w/ the following heading:
New 225-HP, 4-stroke Yamaha--1993 Outrage 21
You will find a prop chart based on testing 5 props on my new Y/O-21. I hope that this helps. Top speed has been a consistent 46 MPH, without loosing acceleration w/ a 17 (P) x 15.25 (D) - SS Salt Water Series Yamaha 3 blade prop - my final selection.
posted 03-17-2004 05:05 PM ET (US)
VMG and jeep9221,
Thank you- both your replies are very useful to me. Explains why I was only getting 5200 rpms out of her with a 19 pitch prop. Looks like the 17 pitch is the one for this boat with a 225 HP. The mirage was also recommended by the person who reconditioned my LaserII last fall.
They are supposed to pick up the boat this Friday for the repower. I think I'll start with a 17 or 19 pitch mirage- I am putting a 250 HP on it and it will be interesting to see how much of a difference the extra 25HP makes in performance. I will see what the dealer recommends also.
Thanks again for your replies. I'll post a "performance report" when she is broken in!
posted 03-17-2004 07:32 PM ET (US)
At the time I bought the boat I was told the Yam SWS props are very similar to the M+ in performance. Deciding factor in this instance was significant price difference. Note the mid-range performance of the SWS prop compared to the others of similar pitch (on Jeep's chart) -- all that diameter (and cupping) pushes alotta water.
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