Propeller help

[FishnhuntOR]

I recently bought a Weldcraft maverick 186 DV with off shore bracket, 115 main and 6 horse kicker.
Motors run fine but the boat seams to be stern heavy and has poor hole shot, Even with just Me and my son. Once she gets going she's fast and a smooth girl. With more people she is slow getting on plane as well.
I want better holeshot and plane sooner.
Especially if I plan on Pulling my kids this summer.
Prop on there now is aluminum 3x14x21 and has some nicks and rough edges on it. It needs a new prop.

Should I go stainless? 4 blade? Less or more of a pitch?
Thanks in advance


Thanks in advance

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[Caveman Jim]

I'd talk to a professional about this but I can tell you from experience with outboard jets that impellers that are nicked or worn will cost you a quick hole shot.
Good luck finding a solution.

 

[Capn Jack]

First clean the prop blades up. Then check your top RPM with a normal load in the boat. If you are over the rated RPM. You may want to increase pitch. If you are under, you may want to decrease pitch. Either way you will need to establish a benchmark to start from. Sometime you can get by just by having the blades cupped.

(Think I got that straight, but it's late.)

 

[DeltaRose]

21" pitch is too much pitch for a heavier boat. My guess is you need to be in the 17" pitch range, and possibly a four blade prop to help with lift. You will lose some top end performance but will have a better hole shot and the ability to stay on plane at lower speed.

Just my $0.02, as others have said consult a professional….

 

[FishnhuntOR]

I've seen some 19 pitch .
Maybe even 4 blade 19?
Captain jack, what do you mean check my top RPM? I know what rpms are, but am I suppose To be going certain speed or ?

 

[DirectDrive]

I recently bought a Weldcraft maverick 186 DV with off shore bracket, 115 main and 6 horse kicker.
Motors run fine but the boat seams to be stern heavy and has poor hole shot, Even with just Me and my son. Once she gets going she's fast and a smooth girl. With more people she is slow getting on plane as well.
I want better holeshot and plane sooner.
Especially if I plan on Pulling my kids this summer.
Prop on there now is aluminum 3x14x21 and has some nicks and rough edges on it. It needs a new prop.

Should I go stainless? 4 blade? Less or more of a pitch?
Thanks in advance


Thanks in advance

I worked for a boat shop when I was a kid.
When setting up a new boat we would go out with about 4 different props.
We would switch them out until we got the boat running on plane, WOT and not over manufacturer's recommended RPM range.

I suggest you contact a dealer that routinely sells your brand of outboard motor and see if he has some props for you to try. He should also be able to offer advice for propping your hull.
If you can swap out the props he might just want a deposit.
If not, then perhaps he could arrange to prop your boat.

 

[osprey]

Boat dealers quite often overprop (too much pitch and or diameter) boats to achieve attractive top end speeds on a very lightly loaded boat. It is the wrong way to prop a boat and it will shorten the motors service life considerably. The proper way to prop is with the boat loaded to your normal intended load. Get four big buddies a large cooler full of ice and beverages and take them out with a full tank of gas. At full throttle and boat trimmed properly you should be able to reach full rated rpm or close. If you can't you are overpropped. Some boats that are naturally stern heavy can benefit from a 4 blade prop as they provide stern lift and will allow boat to run flatter. Some boats (mine) can become a handful in a big following sea with the additional stern lift a 4 blade provides as it can induce bow steer. From your description it sounds like you are overpropped and could benefit from a 4 blade as well. When going to a 4 blade you will have to reduce pitch even more to account for that extra blade in the water. Prop selection is mostly science with some luck mixed in. Good luck!

 

[bbbass]

All good advice here.

In my experience as the owner of a number of waterski craft and a bass boat, the 17" pitch will provide a better hole shot and get skiers up quicker, the 21" pitch will provide more top end speed. It's a trade off; you don't get both. A 19" pitch is probably a compromise but might still give you some of what you want w/o making the boat too slow.

But I never had a 4 blade prop, might be nice for you to try one out!!

 

[Capn Jack]

^^^ See all of the above ^^^

I've never used a 4 bladed prop, so I don't know of any advantages over a 3 bladed prop.
Heck! The Arneson (?) Drives run with the props half out of the water and the props look
more like a S.S. Screw than a propeller. Go figure....

 

[Darren Summers]

Let me help you out here I used to build props and impellers in Alaska. You're using too much pitch I would suggest 17 pitch, a 21 pitch prop would be more appropriate on a larger outboard such as a 200hp. Don't get caught up in the run faster game generally sought after by many boat owners. You will get cavitation and lots of stress on your transmission.

 

[FishnhuntOR]

Thanks everyone
I ended up getting a 4 blade 13.25", 17 pitch Hustler propeller from turning point. It was 88$ And 30 for kit adaptor.
Figured it Saves me bunch of time going to prop shops and what not. And 100$ isn't going to kill me.
it can't be worse than what it is now

 

[Mikej]

Thanks everyone
I ended up getting a 4 blade 13.25", 17 pitch Hustler propeller from turning point. It was 88$ And 30 for kit adaptor.
Figured it Saves me bunch of time going to prop shops and what not. And 100$ isn't going to kill me.
it can't be worse than what it is now

Not that I can help any more with all the other info given. But I'm curious what RPMs you were turning at Wide open throttle (WOT)? If your not hitting recommended top RPM for the motor your not getting proper (pun?) prop perfomance. With MY boat, little 17.5 Smoker Craft windshield boat. I decided that because my original prop was slightly tweaked after some years that I ought to replace it and put the original as a spare. I got a non-Merc prop (Save $$) of same pitch and diameter. The thing was a DOG. Couldn't believe it. It was a returnable prop, so I took it back and went with the extra $30.00 Merc OEM prop and was golden again.

 

[FishnhuntOR]

Not that I can help any more with all the other info given. But I'm curious what RPMs you were turning at Wide open throttle (WOT)? If your not hitting recommended top RPM for the motor your not getting proper (pun?) prop perfomance. With MY boat, little 17.5 Smoker Craft windshield boat. I decided that because my original prop was slightly tweaked after some years that I ought to replace it and put the original as a spare. I got a non-Merc prop (Save $$) of same pitch and diameter. The thing was a DOG. Couldn't believe it. It was a returnable prop, so I took it back and went with the extra $30.00 Merc OEM prop and was golden again.

Had the boat out only hand full of times and only once where I opened it on a Calm day. I didn't really pay attention to RPMs.
One other time When I did pick up my buddy and his 2 boys. So 2 men and 3 boys it took my boat minutes before she planned and I had to have the boys come forward as I did mention the boat seems really stern heavy..
Worse case the 17 will be my summer prop and I'll get a 19 pitch for rest of the year.
I'll keep you posted

 

[Capn Jack]

Try thinking of your boat as an airplane. It has to be balanced, or you will never get onto a plane. How could an airplane ever take off with everyone sitting in the tail?

 

[Darren Summers]

Lots of captains carry more then one prop to adjust for their load. It's kind of like gears in a cars transmission. With a small vessel some people actually prefer a progressive prop this might be a consideration in your case.

 

[FishnhuntOR]

Try thinking of your boat as an airplane. It has to be balanced, or you will never get onto a plane. How could an airplane ever take off with everyone sitting in the tail?

So my buddy and I were up front. 3 Boys, 8-12 years old are loading my boat Down so much it's takes minutes at almost full throttle to plane and you think load distribution is the problem?
I maybe a newb, but that just seems strange to me. Now 3, 200 pond guys, I'd give you that

 

[Arne K]

That Turning Point 4 blade is a good prop. I have a 15p one on my Yamaha F115 powered Tolman Skiff. If you're taking that long to get on plane, you're horribly over-propped. The 17 will probably be close but do check your RPM's at wide open throttle and adjust from there. It never hurts to have a spare, anyway. Another thing to consider is the altitude of the body of water you're on. If you're 17 pitch is great on the Willamette, you'll probably need a 15 or even less on a mountain lake at 5000'. Also, being under-propped isn't terrible as long as you pay attention to RPM's and don't over rev the engine. The lower pitch will get you more responsiveness when loaded heavily.

 

[Ura-Ki]

Don't think the 4 blade is gonna be any help here! boats need to dig hard, with the power they have, and to do that, less blades, or less pitch and diameter equals a motor that can build it's peak power quicker, which is what get's you up on plane and moving! Another thing here that nobody has yet touched on is thrust angle, I.E. thrust centerline! It's why many boats have adjustable tilt and or trim tabs! Might anna look at the whole set up before blaming the prop! That said, the listed specs in the O.P. are a bit on the aggressive side for a 115 H.P. motor, and while a 17 pitch prop should dig better, having 4 blades negates the advantage, I.E. More isn't better in this case!

Airplanes have the same issues, look at my AVATAR, that's a 12 pitch 84 inch prop, turns fast and climbs hard, but doesn't cruise very fast, but 0 to 30 knots is instant. Change it out to a 11 pitch 78 inch 3 blade and it takes forever to get up to flying speed and just as long to climb, but goes like hell up top! Best combo is way MORE power with a constant speed 3 blade prop!

 

[Arne K]

My experience (with boats only) is different. Prop makers adjust the diameter of 4 blade props to compensate for the extra surface area. It's also a little bit of a myth that you need to drop pitch when going from a 3 blade to a 4 blade for the same reason. My boat is 24' and runs over 4,000lbs when chasing tuna. I get it done with an F115 and am able to be on plane before 11mph with a 4 blade prop.

 

[LDmax]

Don't think the 4 blade is gonna be any help here! boats need to dig hard, with the power they have, and to do that, less blades, or less pitch and diameter equals a motor that can build it's peak power quicker, which is what get's you up on plane and moving! Another thing here that nobody has yet touched on is thrust angle, I.E. thrust centerline! It's why many boats have adjustable tilt and or trim tabs! Might anna look at the whole set up before blaming the prop! That said, the listed specs in the O.P. are a bit on the aggressive side for a 115 H.P. motor, and while a 17 pitch prop should dig better, having 4 blades negates the advantage, I.E. More isn't better in this case!

Airplanes have the same issues, look at my AVATAR, that's a 12 pitch 84 inch prop, turns fast and climbs hard, but doesn't cruise very fast, but 0 to 30 knots is instant. Change it out to a 11 pitch 78 inch 3 blade and it takes forever to get up to flying speed and just as long to climb, but goes like hell up top! Best combo is way MORE power with a constant speed 3 blade prop!

If brute force isn't doing the trick, you're not using enough brute force (aviation proverb).