What prop on a 18ft w/a 115 tower of power

[fishdog4449]

Re: What prop on a 18ft w/a 115 tower of power

I had a 115 tower on a heavy 18' runabout, i had two props a 17p hustler vented aluminum (aggressive pitch, comparable to stainless) for watersports and a vented 19p hustler for cruising. wot with the 19 would be 5700 and holeshot was great the vent holes really allowed the motor to spin up to 3k or so before the prop would bite

 

[earringboy]

Re: What prop on a 18ft w/a 115 tower of power

Installed new impeller and the 21p prop. Sunday looks good for a test run. Seems these 115's are all over the place as far as the prop/rpm goes, I suppose it all has to do wiht hull design and weight. We will see tomorrow afternoon if all goes according to plan and Murphy stays away.

 

[earringboy]

Re: What prop on a 18ft w/a 115 tower of power

hit the water today.
21p allowed 4950-5000 rpm @41mph.
It will come off and the hunt for a 19 has begun. I will put the 15 back on until I come up with a 19 or 17 to test. Kinda thought the 21 was going to be at 4900, so no surprises. An 18 might be just the right blend of throw you r wife off her seat hole shot and top end. Although I would recommend NOT dumping your wife outa her chair, far to dangerous on many levels.

 

[earringboy]

Re: What prop on a 18ft w/a 115 tower of power

Anybody got any suggestions as to what brand of propeller to go with?
I think an 18 would be just right but I can only find those in stainless and that is way over buget right now.
19p should put the motor at 5300 to 5400
18p should be 5500 to 5600
17p should be 5700 to 5800

what would you guys use?

 

[steelespike]

Re: What prop on a 18ft w/a 115 tower of power

If you want to split hairs you could have the 19 repitched down or the 17 repitched up. probably one is prefered over the other.You could also have cup added or removed to change the apparent pitch.Increasing cup may allow more motor height.

 

[earringboy]

Re: What prop on a 18ft w/a 115 tower of power

I think I will send my 17p in to be rebuilt and have it repitched to 18 and maybe see what they think about adding cup, found a shop that will do it at a reasonable price. I was also thinking of getting a Michigan Vortex in 19p. Any thoughts? What can I expect by raising the motor?

 

[trendsetter240]

Re: What prop on a 18ft w/a 115 tower of power

I think I will send my 17p in to be rebuilt and have it repitched to 18 and maybe see what they think about adding cup, found a shop that will do it at a reasonable price. I was also thinking of getting a Michigan Vortex in 19p. Any thoughts? What can I expect by raising the motor?

Raising the motor will allow more RPM and speed in most cases. Depending upon how low your motor is now...

If the anti-ventilation plate is currently below the hull and you raise it to 1/2 to 1 inch above the hull you should see a few hundred RPM and 1 or 2 MPH gain.

Personally, I would go with a solas amita 4-blade 17p. Second choice would be the TP hustler 17p. Both are inexpensive. The amita will give you better low end and cruise handling while the hustler will give you good hole shot and a few more mph on the top end.

I find the hustler is a little loose at slower speeds.

Cheers.

 

[earringboy]

Re: What prop on a 18ft w/a 115 tower of power

Why a 4 blade?
Also do the Solas and Vortex have better blades design than the old stlye Mercury factory props? Thinner cross sections with less drag and better performance? And are the Solas blades thiner due to their squeeze casting?
What about the Volvo props? Larger exhaust hub?

tested so far and results:

Mercury Factory 21p 12 3/4 prop=4950rpm & 41mph on fairly calm water and low wind. Not a rebuilt prop.

Merc Factory 15p 6000 rpm and 36 or so mph, this was a rebuilt prop.

Both were old style non-flo torq props.

 

[trendsetter240]

Re: What prop on a 18ft w/a 115 tower of power

Why a 4-blade? If you search this prop forum you will find loads of info on the 3blade vs 4blade question. Personally I like the smooth power and grip at speeds just above plane. They grip like nothing else in the 4000 to 5000 RPM range on my boat. And yes, 4 blades can be cast thinner than the same design 3 blade.

I recomended solas because I have used one and they are inexpensive and provided good results for the cost. The prop on my boat now is a Solas HR Titan 4 blade stainless and I absolutely love the performance.

No experience with Volvo props but also have not read or heard anything that would make me believe they are any better than the other options available.

 

[earringboy]

Re: What prop on a 18ft w/a 115 tower of power

I have read many posts on 3 v 4 today and do think I will go with a Solas 4 blade aluminum 12 3/4dia x 17p. I am leaning towards the rubex version, what do you all think of a prop with a user seviceable hub as opposed to the traditional press in hub?

My motor should probably be raised as well, but for now I will stick with changing the prop

13 3/4 15p Merc prop 6000rpm @36mph or so, saw the tach and backed to quick to see exactly how fast GPS read

12 3/4 21p Merc prop 4900rpm @ 41mph

 

[earringboy]

Re: What prop on a 18ft w/a 115 tower of power

I found a Michigan Wheel Apollo 13 1/8 x 19 prop used on craigslist near me, it has a few small dings on the edges, what do you guys think of this prop?

 

[JaseBosto]

Re: What prop on a 18ft w/a 115 tower of power

I think you should file the dings out. You would be surprised what a small ding can do.

 

[earringboy]

Re: What prop on a 18ft w/a 115 tower of power

I planned on touching up the edge, what do you think of that prop as compared to others? I am a goldsmith and have access to great stainless polishing compounds.

 

[Dhadley]

Re: What prop on a 18ft w/a 115 tower of power

We're still talking about aluminum props only, right?

 

[earringboy]

Re: What prop on a 18ft w/a 115 tower of power

So far I have had ONLY aluminum stock mercury props with the pressed in hub. I plan on picking up a 3 blade Michigan Wheel Apollo Stainless Steel 13 1/8 x 19p on Thursday and giving that a shot. It is vented and has the removeable hub. It is used and in good condition, will need a few nicks removed but they are very small, $150.00

 

[Dhadley]

Re: What prop on a 18ft w/a 115 tower of power

150.00 for a nicked up prop is not a good deal. Your testing will not prove anything since the ss prop is not in new condition. Put the 150 toward a new ss prop to get a true idea of what's going on.

 

[earringboy]

Re: What prop on a 18ft w/a 115 tower of power

okay. I was looking at it due to price, and the nicks are all less than 1/16 inch deep I could clean up the edge in 10 min or so. Any suggestions in a new Aluminum prop, 3 blades or 4? Or would you suggest stainless? I am in the north all freshwater. What would you put on your boat?

 

[earringboy]

Re: What prop on a 18ft w/a 115 tower of power

mercury black max/quicksilver black diamond in 17p or the solas Amita 4 with the press in hub in 17p?

 

[trendsetter240]

Re: What prop on a 18ft w/a 115 tower of power

mercury black max/quicksilver black diamond in 17p or the solas Amita 4 with the press in hub in 17p?

As I mentioned before, the amita 4 is a very good option for an inexpensive aluminium prop for your setup. The amita 4 will be better than your current merc stock 19p. If you want the perfect prop you will need to try a few stainless props.

Go with the amita 4 17p and see if you still want another prop. My expectation is that it will be all that you need.

 

[earringboy]

Re: What prop on a 18ft w/a 115 tower of power

I think I will order the Amita 4, do you think I am right with a 17p? Traditional hub or the rubex? The stock Merc 21p only allowed 4900 rpm, I guess I would rather watch the tach and back off than not have enough power, especially if I have extra passengers. Thanks Trendsetter420.