4 blade work best for some boats?

[Shoneycutt1976]

2003 x17 , 115 mariner 10" atlas 13.5 x 22 laser 2 prop. 50 mph gps @ 5200. Full tank , livewell and lot of gear. Doesnt seam to get enough lift. Used to have a 90 hp yamaha , turbo 13.125 x 17 4 blade and would ride higher in the water now it seams to just lift the back of the boat more. Found a couple o 4 blade props. Turbo 13.750 x 22 and a renegade 13.5 x 23. Any suggestions?

[Ranger391v]

I've never liked the Laser prop. It was a good prop back in it's day, but that was like in the 80's or early 90's. I always liked the 4 blades (namely the Trophy Plus) on 16' & 17' hyperlift hulls (like your X17) with midrange HP motors/gearcases (basically 70hp to 115hp).

Other props that ran good on 16'/17' hyperlifts:
There is also a prop known as a V4 version Raker (not to be confused with the most common version which is for V6 engines). Depending on how old it is, etc. you'll have to rehub the prop to fit your motor (unless it's a JohnRude) and the hardest part is playing with thrust washers and rear spacers to make it properly fit. With that said, it is possible as I use to do it on a Yamaha 75/90 all the time ...... but it helped that I had a box full of junk like that to play with too. We did the same thing with the Renegade prop as well (again, another OMC/BRP JohnRude prop). When playing with the Renegade, we always got the same one used on the V6 engines .... this is due to the prop's barrel becomes a 'through hub' prop on the smaller gearcases whereas on a V6 gearcase it's a 'over & through prop'. The Trophy Plus is the same way. Yamaha has a v4 version of their Pro Series prop. It's a 3 blade just like the Raker .... and performance is similar. The Raker and Pro Series tend to be great if you're mainly concerned with top speed. The 4 blades (Trophy Plus and Renegade) give up very little on top end (and depending on setup maybe none). But the 4 blades do everything else much better on these 16'/17' hyperlift hulls.

All of these props (Trophy Plus, mini-Raker, Renegade and mini-Pro Series) work great on the 16'/17' hyperlifts. Some just take more work to get to properly fit depending on engine brand. Again, the easiest thing to do is get a Trophy Plus prop and pick the correct Merc Hub Kit for your motor and be done with it. With it being a Mariner, the hub kit for the Trophy is that much easier to do too.

Good Luck!
-391v

[Shoneycutt1976]

Thanks for the advice. I have a trophy plus here but it's a 25 pitch I believe. Way to much for my boat. If I'm if I'm able to pull 13 and 1/2 by 22. Laser 2 prop, do you think I could pull a 13 inch by 22 for blade such as a trophy or a turbo? Not really concerned about top speed. Just need more bow lift. . The Yamaha lifted great with a turbo 4 blade 17 pitch. This other setup just seems to plow the front end into the water.

[Ranger391v]

Yea, 25" will be way too much pitch. I want to say we were running something like a 21" Trophy when running the 115 Yamaha 2 strokes. I don't know how your model 115 compares to the gear ratio of the Yamaha's. With that said, I'd try to find one around that pitch.

Also, keep in mind, that Turbo 4 blade is not near as good a prop as that Trophy Plus will be. I used to have a 4 blade Turbo as well, and the Trophy Plus was that much better. That Renegade you mentioned above in your original post, it will run very similar to a Trophy. Thus if that prop is re-hubbed to fit your Mariner, I'd try it at least. Just make sure the thrust washer fits properly, as a JohnRude prop shaft tapers differently than a Merc/Mariner.

[Shoneycutt1976]

Thanks again. I'm thinking I'll look for 13x 21. To get started.

[Ranger391v]

Your welcome Sir! And good Luck!!!!! These short hyper' hulls can be a handful trying to get to run right. The 2 things that I found that greatly helped make them act right (meaning holeshot to mid-range and then top end) is a 4 blade prop and a hydraulic jackplate (which I remember reading above you have an Atlas). Once the 4 blade takes care of the majority of 'all around handling', that hydraulic jackplate will let you raise the motor for best WOT speeds. My findings (and others) is that the prop shaft height really needs to be deeper on holeshot to mid-range so the boat still lifts the bow decently. We found that if you leave the prop shaft height high for WOT speeds that the hull runs extremely flat until you get to WOT. We were also plugging out top water intake holes too. But you have to really be careful when doing this as you can pop a powerhead from lack of water quickly doing that.

Hope it helps!
-391v

[Shoneycutt1976]

I'll keep you posted with my results.

[Shoneycutt1976]

I have an update. So I didn't realize when I switch Motors that there was settings on my tachometer. Guess I need to read the destructions more LOL. So after getting that fixed and calibrated took out the late today and the boat comes out of the hole really strong. As soon as it comes up on plane it takes a nosedive. Then when you start to trim it up at about 4,000 RPM at 42 miles an hour the boat porpoises really bad. When you lay into it and get it trimmed up the boat will run 50 miles an hour but it's turning 62 to 6300 RPM and then the back end of the boat gets loose and kick sideways. Question is I'm still looking for a 4 blade but I'm trying to determine what pitch I need and one other thing I run into is my gearcase measures 4 and 1/4 inch. Most everything I find is in the 14 inch diameter range but they don't tell you Hub diameter. I do know that the 150s xr2 xr4 and so have a 4 and 3/4 inch gearbox. Also the service manual State's wide open throttle she should be 5250. The boat that it was on before (16' cajun )run really close to that

[Ranger391v]

All pretty typical results for both the 16'/17' hyperlifts and a Laser (slipping). Same recommendations above still apply. The Trophy Plus will cure some of the lift and porpoising issues and still allow the boat to run a really good top end. The 3 blade performance props (Raker, Pro Series ........ dang sure not a Laser) will get about 1mph faster than the Trophy, but will not lift in the midrange HP's like the Trophy.

If it's a Trophy Plus for a v6 gear case, it will fit your midrange HP gear case too. It's just that you're fixing to make it become a through hub exhaust prop instead of on over-&-through exhaust prop like originally designed when used on a v6. Still use the proper hub kit for your Mariner 115. Truthfully, whenever I ran a Trophy Plus on a v6 I'd run them with the cavitation ring to close up that gap anyway. I never did like over-&-through exhaust props anyway.LOL

Pitch is a guess. I'd guess 21"/22" starting out with. Know your prop shaft heights below the pad on your Atlas. I would start it at 4.5" below the pad and raise it no higher than 3.5" below the pad, unless you have a water pressure gauge. Optimal WOT setting will most likely be higher, but there is no way I'd chance raising the motor any higher without a water pressure gauge. Also, make sure you're measuring prop shaft height on level concrete with a hull leveled and cav. plate level.

[Shoneycutt1976]

Cool deal thanks. Have a water preasure gauge also. Found a trophy plus 13 3/4 x 21 . I'll start with that. Forgot to ask about prop diameters and how they affect performance. Again, thanks for the advice.