Stern lifting prop

[msojjo]

Can anyone tell me what props i should be looking at. I have a very heavy stern boat and am looking for a stern lifting prop, but don't know what brands and makes i should be looking at, any help would be helpful.

 

[steelespike]

Re: Stern lifting prop

can't be too specific but 4 blade props work very well to get a boat up on plane and
keep it there with less throttle and diddling. Wouldn't hurt to give us the details of
your boat.The Solas Amita 4 blade is very predictable, effective and reasonable.
tell us about your present prop boat specs and your present performance, max rpm and speed.

 

[dan t.]

Re: Stern lifting prop

You want a non raked prop with a large blade area,not all 4 blades fit this criteria, some such as the alpha 4 give bow lift

 

[msojjo]

Re: Stern lifting prop

I'm currently running a 17 pitch michican wheel balistic prop. It's stainless steel three blade. I have a 20 foot bowrider that averages in weight around 4200 lbs with fuel and people. I have a 350 mag and wide open throttle is 4900 trimed up, with 5000 rpm max recomended by merc.

 

[rallyart]

Re: Stern lifting prop

Two Merc props that will get you out faster would be the High 5 and the Vensura which is a 4 blade. Both are stainless. I'd stay the same pitch and prefer the Vensura but many like the High 5.
The props won't lift the stern but they give you more push so you spend less time getting up to speed.

 

[Dhadley]

Re: Stern lifting prop

Are you looking for stern lift at holeshot or while on plane thru wide open?

 

[msojjo]

Re: Stern lifting prop

Are you looking for stern lift at holeshot or while on plane thru wide open?

I'm sorry, forgot to add that. Looking for something at holeshot, with such a heavy stern it just digs in and pops the bow up in the air making it take quite a while to get onto plane. once on plane i have no problems. I know that putting trim tabs would help me greatly but i am not to excited about drilling more holes into my transom.

 

[Tail_Gunner]

Re: Stern lifting prop

• Manufacturer:Mercruiser
• Horsepower: 300 HP
• Years: All Years

• Model: Bravo One 350 Magnum Sterndrive
• Specs: Thru Hub Exhaust & 15 Tooth Spline, 4-? Gearcase
• Max RPM: 4800-5200 RPM

If that is a mag your target is 5200....Its a valve train restriction not the crank...5.7 motors can turn 7000 rpm and live well....your drive doesnt like more than 6000

Ballastic props are not known for being effictive on I/O's

Lets try to get this linear...What is your speed and rpm @ wot....A 300 hp motor should have incredbile response on a 20 ft boat..even with 1.5 gearing.

 

[msojjo]

Re: Stern lifting prop

Yes it is the mpi 350 mag with the bravo drive. It say's on the air cleaner shroud that my recomended range is 4600 to 5000 rpm. I've been hearing more and more that a balistic isn't good for my boat. With the 17 pitch prop i'm running at 4900 rpm and a speed of 57 on the speedo, so i'm guessing that equates to 50 to 52? I haven't had a chance to gps it yet, but i know that i'm flying.

 

[rallyart]

Re: Stern lifting prop

4900 rpm = 294,000 revs/hour
divided by 1.5 for gear ratio is 196,000 prop revs/hour
17" per rev = 3,332,000 inches/hour = 52.6 miles per hour
less 10% prop slip = about 47 miles per hour real maximum speed.

The speedo is probably wrong but the tach might be wrong, or the pitch on the prop might be higher than it is stated on the prop

(if it's a 15" diameter prop the tip of the blade is travelling 146 MPH)
(Sorry, my curiosity kept me at the calculator too long)

 

[msojjo]

Re: Stern lifting prop

I know that the prop is a 17 pitch, new and has not been worked on. My tach is brand new this summer, i replaced it because the old one would jump around when at low rpm's now it's good. I know the speedo is probably off, just don't know how much, they all are arn't they.

 

[rallyart]

Re: Stern lifting prop

Only thing worse than a boat speedo is a boat fuel guage.

 

[Robbabob]

Re: Stern lifting prop

I don't know what to add. "IF" you have 300HP using a 17" pitch, your 20' should be jumping out of the water (and on plane), even at 4,200 pounds.

I assume you have the weight distributed forward as best as possible. Gas, ice chests and guests all in the stern area won't help your cause.

Now, if you want all the top end AND improve hole shot, it's time to start drilling more holes (for the tabs). Changing the prop to give better hole shot will only reduce your top speed, and potentially cause too high an RPM at WOT.

If you are fine with losing top end, go with a suitable 17" 4-blade. It'll be all in the testing.

Good luck!

 

[sstocker31]

Re: Stern lifting prop

I'm kind of new to all this boating thing, but while reasearching the props that came with my boat I discovered that they are "stern lifting props"
Have a look at mercury marine "offshore series" of props.
I can't offer any feedback on these, as I haven't had the chance to use them yet.

 

[JimS123]

Re: Stern lifting prop

We wanted stern lift, less bow rise and better hole shot. Went with a Precision Propeller Turbo Prop I and it did all we asked it to do and more.

We provided the appropriate specs (boat model, engine rpm, speed, etc.) to their TS department and they recommended the right prop.

They guaranteed it would do what we wanted, but really they missed the mark. The speed was 2 mph FASTER than they said.

They have an awesome database and they really know what they are doing. Customer Service is dead today, but not there.

Do you think I'm highly impressed?

 

[Tail_Gunner]

Re: Stern lifting prop

Yes it is the mpi 350 mag with the bravo drive. It say's on the air cleaner shroud that my recomended range is 4600 to 5000 rpm. I've been hearing more and more that a balistic isn't good for my boat. With the 17 pitch prop i'm running at 4900 rpm and a speed of 57 on the speedo, so i'm guessing that equates to 50 to 52? I haven't had a chance to gps it yet, but i know that i'm flying.

Id like to help but...1.5 gearing 17p prop @ 4900 yeilds 53mph and that no slip...Check your tach closely..boat tachs are worse than the weatherman..

Dont get me wrong here if your turning 4900 rpm with a load of people that makes some sense with your boat engine combo...can you post your gearing its usally on the leg of the outdrive stamped alumin tab..There are some very good props out there just getting the right pitch is the question for the load your running..

Aka do you run that boat with 1000 lbs of people and equipment to 4900 rpm with a 17p prop

 

[msojjo]

Re: Stern lifting prop

Id like to help but...1.5 gearing 17p prop @ 4900 yeilds 53mph and that no slip...Check your tach closely..boat tachs are worse than the weatherman..

Dont get me wrong here if your turning 4900 rpm with a load of people that makes some sense with your boat engine combo...can you post your gearing its usally on the leg of the outdrive stamped alumin tab..There are some very good props out there just getting the right pitch is the question for the load your running..

Aka do you run that boat with 1000 lbs of people and equipment to 4900 rpm with a 17p prop

I have only run the boat to 4900 rpm with just me and fuel with the prop. I am 200 lbs, and usually run with a half tank or so, 25 gal. I have the bravo 1 drive with the 1.50 gears.

 

[msojjo]

Re: Stern lifting prop

I don't know what to add. "IF" you have 300HP using a 17" pitch, your 20' should be jumping out of the water (and on plane), even at 4,200 pounds.

I assume you have the weight distributed forward as best as possible. Gas, ice chests and guests all in the stern area won't help your cause.

Now, if you want all the top end AND improve hole shot, it's time to start drilling more holes (for the tabs). Changing the prop to give better hole shot will only reduce your top speed, and potentially cause too high an RPM at WOT.

If you are fine with losing top end, go with a suitable 17" 4-blade. It'll be all in the testing.

Good luck!

That's why i purchased the boat, with the 350mag i thought i would fly out of the hole. I really don't keep much in the boat, ski's and jackets are all under the floor in the locker, midway. Fuel tank is probably back a little farther than it should be, just in front of the motor. Duel batteries next to motor, and some odd's and ends wrenches, screwdrivers, filters, oil, and a few other things in a bucket next to the motor compartment. I don't care really about top end, even now with a 17 it feels too fast, i live on a smaller lake, so i just want hole shot, i can watch my rpm's.

 

[Silver Eagle]

Re: Stern lifting prop

That's why i purchased the boat, with the 350mag i thought i would fly out of the hole. I really don't keep much in the boat, ski's and jackets are all under the floor in the locker, midway. Fuel tank is probably back a little farther than it should be, just in front of the motor. Duel batteries next to motor, and some odd's and ends wrenches, screwdrivers, filters, oil, and a few other things in a bucket next to the motor compartment. I don't care really about top end, even now with a 17 it feels too fast, i live on a smaller lake, so i just want hole shot, i can watch my rpm's.

When I had my 21 ft bow rider I used a 17 inch three blade prop. I tried a Four blade and the planning wasn't as good and the vibration was awful. How many people are in your boat ? I had at the most four adults .I always put the heavy one up front. I told them I didn't want the boat to come out of the water.It had a 230 hp Merc I/O

 

[Tail_Gunner]

Re: Stern lifting prop

Well its a 21' open bow...probably 3500 lbs wet it has to have a 21 degree dead rise with 1.5 gearing...If all that is right.. a heavy deep v does have a bit more of a time struggle getting out of the hole ...although there are some that would call a 20-21 shallow rise

You seem not intrested in top speed so here's a prop in a 16 that has some of the strongest lifing quality's you will find....
Turbo 2+2 TH Series

....... dont ask

Get that in a 16 pitch and you will be happy maybe you will keep the same top end...That prop line has tremdous lift

Just google the above it should take you to a site that there priced right..Yep it comes up good luck