Prop help

Hey guys I run a 2007 Crestliner 1750 fishhawk with a merc 115 4-stroke. I’m trying to find the right prop for my boat. I was running a hustler 13 3/4×15 aluminum and I would max out at 38-40 mph and according to the tach I was at about 6000 rpms. It’s a little slow on plane but I tried a 13 1/4×17 and figured I’d add a hydrofoil if things got too bad in that dept. Well I ran it this weekend and it went totally backwards. My plane time was similar but instead of gaining speed I lost a ton. I maxed out at 34 mph and was at about 6400 rpms and if I trimmed up even just a little I’d go over my max rpms and loose speed and forward bite. I don’t know if this is prop wash. So now I’m thinking of trying a13x19. But I’m just confused how I lost so much top end going from a 15″ to a 17″. Thanks for the help.

Why are you dropping the diameter of the prop, sounds like you need the surface area.

I have a 115 opti on a 2006 monark king 175 w/ a full windshield (similar boat) that I played with some props on, heres my results:

-Came with a 13″ or so x 21, didn’t know much about proping and just slapped a whale tail on and called it good because of issues getting on plane=5100-5200 rpm, and 38 mph on a perfect day. The whale tail actually caused the bow to slam down hard when crossing wakes and big waves(noticed immediatly after I took it off for the prop testing that there was a much more cusion like skip in this situation)

-after 5 years of dealing with it I tried a 13.25×19 michigan wheel basic alum, removed the tail and gave it a shot=5650rpm(sweet spot) and 41-41.5 mph, excelent improvement

-Then Propman on here recommended the Quicksilver Nemesis 4-blade , so I figured I would give it a shot in a 12.75×19=5350-5400 rpm(less stress on the motor at that rpm) better hole shot, and just a hair over 43 mph!

This is the same prop as the Mercury Spitfire but about 40 bucks cheaper.

Propulsion Inc in Hudson ordered it in for me and gave me 30 days to try it. They offered a full refund if unsatisfied, and undamaged of course, but I was very happy with it so didn’t need to return it!

The Diameter seemed a little small on it but I was informed that with the extra blade the surface area is still there to make up the difference.

I would recommend at least giving it a shot! Don’t know unless you try it! Every Boat and motor has its own unique set up depending on how you have it rigged, the weight distributed and other variables from what I’ve read/heard.

I run the same boat in a 2003 with a 115 Yammy 4 stroke. The 13 X 19 is my favorite over all prop giving me about 40 MPH GPS. The 13 X 21 is slower out of the hole but eventually gets 41.5 MPH GPS. I have never exceeded 6000 RPM and rarely go over 5000. I can get about 33-34 mph at 5000 with a lot less gas burned. Fast enough for me…

I had a 1750 fishawk with a 115 merc opti-max and ran a 13 1/2X21 three bladed prop.Slow on hole shot but good top end in the 46 to 48 range. tried a 131/2 X19 three blade and gained on hole shot but lost about 4 to 5 mph. RPM with 21 was abbout 5700 and with 19 ran about5900 to 6000 grand.how is your motor mounted on the transom? Mine was set about an inch up from the transom

Maybe try giving Crestliner a call, ask to talk with someone familiar with testing the boats out. Most likely they have already tested out that particular setup you have and have a good idea on what prop to try out. It never hurts to ask, they are a good source to start with.

sounds like it went just the way it should have with the changes you made! you made a jump from a 15 to 17 pitch but lost a lot more contact with the water your mistake was downsizing on the prop!

stick with the 13 3/4 and adjust pitch from there!

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Hey guys I run a 2007 Crestliner 1750 fishhawk with a merc 115 4-stroke. I’m trying to find the right prop for my boat. I was running a hustler 13 3/4×15 aluminum and I would max out at 38-40 mph and according to the tach I was at about 6000 rpms. It’s a little slow on plane but I tried a 13 1/4×17 and figured I’d add a hydrofoil if things got too bad in that dept. Well I ran it this weekend and it went totally backwards. My plane time was similar but instead of gaining speed I lost a ton. I maxed out at 34 mph and was at about 6400 rpms and if I trimmed up even just a little I’d go over my max rpms and loose speed and forward bite. I don’t know if this is prop wash. So now I’m thinking of trying a13x19. But I’m just confused how I lost so much top end going from a 15″ to a 17″. Thanks for the help.

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We’ve had very good results with the new Quicksilver Nemesis 4 blade props if you want to stay in aluminum. For Stainless the Powertech RAF is a excellent prop for your setup.

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We’ve had very good results with the new Quicksilver Nemesis 4 blade props if you want to stay in aluminum. For Stainless the Powertech RAF is a excellent prop for your setup.

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Told ya!! He knows is stuff from what I can tell!

Another thing to check when the boat is on the trailer is to see if the cavitiaion plate(the horizontal “fin” that hangs over the prop) is in line with the bottom of the boat when the motor is trimmed all the way down. It sounds like with the small amount of trim movement you are getting, the motor may be mounted to high on the transom causing immediate cavitation or “prop wash” when trying to trim up. That is just speculation though. Most dealers know how to mount a motor but you may have gotten a rookie rigger that didn’t know how precise this has to be!
I have done a lot of reading trying to figure out my boat proping and came upon a lot of good info!

Queston for Propman, I just bought a 2003 1750 Fishawk with a 115 4-stroke Yamaha with a 25 inch transom. I have a 19p 3 blade aluminum. Top end is 40 mph. I want to keep this one for a spare and get a new aluminum. What do you recommend?
Thanks to all the IDO’ers for all the great post!!!

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Queston for Propman, I just bought a 2003 1750 Fishawk with a 115 4-stroke Yamaha with a 25 inch transom. I have a 19p 3 blade aluminum. Top end is 40 mph. I want to keep this one for a spare and get a new aluminum. What do you recommend?
Thanks to all the IDO’ers for all the great post!!!

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What rpms you running with that 19 pitch?

WOT is around 5500 to 6000.This boat is new to me so I really watch where I am going. I will give you a better answer after my next trip latter this week Thanks for your help

Propman I have a question for you that I think I may know the answer for but not completely sure.
I have a 2012 Smoker Craft Ultima & 115 Yamaha 4 stroke w/ 13″D x 19″p.
Full throttle tilted down it runs 5800 rpms & WOT 6100 rpms.
It takes about 6-8 seconds to plane (just a guess, never actually timed it.) & losses plane around 20 mph. It also seems to loose grip in tight turns.
I would like to have a better hole shot & be able to maintain a lower speed at plain.
I am guessing the quicksilver nemesis 19p is a good solution since I am leaning towards staying with aluminum.
Thank you in advance for any advise you can give.

If you want to stay with aluminum prop, I would for sure try out a Quicksilver Nemesis. It will have better holeshot and grip. A 19 should be what you need.

Thank you for the reply Propman. I just realized this post is a year old, I thought it was from this may. I guess I should have started a new post.
Are the nemesis & the spitfire exactly the same or one any better than the other? As I understand Mercury is the parent company of quicksilver. Or something like that.

Yes quicksilver Nemesis and the Mercury Spitfire are exact same prop, just different part #s.