Prop choice

[Tafflad]

Hi .. I have a Montery 194FS fitted from new with a 4 blade 20" pitch Alluminium prop.
The boat is used for skiing/wakeboarding ... recreational only.

On previuous boats I have fitted a High Five .....

2 questions ...

Q. If I was to fit a High Five ... how do I match the pitch, High Five is in 'odd' pitch size, so would need to go up or down ... which is reccomended ?

Q. Or should I just get a 4 blade stainless in 20" pitch .... Vensura / Tempest ?

 

[steelespike]

Re: Prop choice

Generally a high five is for powerful boats.
And over kill for the money.Selection for a ss 4 blade would depend on your present performance.
But a 20 ss seems reasonable.

 

[Squire]

Re: Prop choice

Hi .. I have a Montery 194FS fitted from new with a 4 blade 20" pitch Alluminium prop.
The boat is used for skiing/wakeboarding ... recreational only.

On previuous boats I have fitted a High Five .....

2 questions ...

Q. If I was to fit a High Five ... how do I match the pitch, High Five is in 'odd' pitch size, so would need to go up or down ... which is reccomended ?

Q. Or should I just get a 4 blade stainless in 20" pitch .... Vensura / Tempest ?

If your current performance puts you in the optimum WOT range I wouldn't rule out a 19" Rev 4 to give you the best overall performance. More money than some of the alternatives but you should be able to find one in the same price range as the High-5.

 

[Tafflad]

Re: Prop choice

The boat is a 19'4" bowrider .... you say High Five is for performance boats, not sure what your criteria for that would be

My last boat a Maxum 1800 SR3 had a High Five (non MPI 4.3L) .........

If there is no real benefit for going to a High Five over a 4 blade prop, then I won't bother.
I can't really tell if I should get a Vensura or Tempest ....
or is there another make I shoul look at.

 

[steelespike]

Re: Prop choice

The boat is a 19'4" bowrider .... you say High Five is for performance boats, not sure what your criteria for that would be

My last boat a Maxum 1800 SR3 had a High Five (non MPI 4.3L) .........

If there is no real benefit for going to a High Five over a 4 blade prop, then I won't bother.
I can't really tell if I should get a Vensura or Tempest ....
or is there another make I shoul look at.

You could probably run a high 5 on a 3.0 but would it be the ideal prop?
And would the cost justify the performance?
Someone with more technical help may be along.
Who ever helps you we will need your wot rpm and gps speed lightly loaded.
If you read the stickys at the top of the prop forum and get us as much info as possible it will help.
We need to be able to evaluate your present setup before we can make an informed suggestion for a prop change,
especially with the cost involved.

 

[Tafflad]

Re: Prop choice

This is not a 3.0L this is a 4.3L MPI (220hp) dry weight of 1406 Kg (3163Lb)
Estimated running weight of 1795 Kg (4040Lb)

I don't have WOT details ... I'll see if I can read it next time I'm out, you say "gps speed lightly loaded." what does this mean .... I have no GPS speed indicator, only the standard speedo which is water pick up off engine drive.
I won't be able to run boat at Max speed as highly unlikely to have suitable water conditions .... but will get rev counter reading of full open throttle while it is accelerating.

 

[callen369]

Re: Prop choice

Hi,

If you feel the need to go to a high five, then I suggest going 19 pitch to keep your hole shot, WOT rpm's, and speed about the same. Of course, that's a big chunk of change, and I'm not sure you'll see a big difference.

Personally my four blade is very smooth and has good hole and top end speed. If your 4 blade is an older prop, you will probably get better results from newer designs in 4 blade.

Can't recommend a brand for stainless, running aluminum down here because of the shallow water. So I went a little on the cheaper side switching from a 3 blade 14.5x21 to a Turning Point 14x21.

 

[Tafflad]

Re: Prop choice

No burning desire for a High Five ..
Boat has a 3 yr old 4 Blade 20" ....

I prefer a SS prop, so just trying to figure out what I need .......... top end isn't an issue.
Makes/models ? to consider welcome advice.

 

[steelespike]

Re: Prop choice

I know your boat is a 4.3;I was saying you could put a high 5 on a 3.0 but would it be ideal based on the cost and performance.
Usually when going to a ss prop from aluminum it is suggested to try the same pitch.(depending on the present performance)
Lightly loaded would be just a driver if you have a 60 gallon tank would be nice if half full or less but not required.
The idea is to see how well the setup performs. See if the rpm and speed make sense and get a better idea for a more
informed prop selection. Often we get we get reported rpm and speeds that aren't possible from the given setup specs.
If you don't have a gps some cell phones have a gps app.

 

[Tafflad]

Re: Prop choice

I know your boat is a 4.3;I was saying you could put a high 5 on a 3.0 but would it be ideal based on the cost and performance.
Usually when going to a ss prop from aluminum it is suggested to try the same pitch.(depending on the present performance)
Lightly loaded would be just a driver if you have a 60 gallon tank would be nice if half full or less but not required.
The idea is to see how well the setup performs. See if the rpm and speed make sense and get a better idea for a more
informed prop selection. Often we get we get reported rpm and speeds that aren't possible from the given setup specs.
If you don't have a gps some cell phones have a gps app.

OK ... I'll try & measure on the w/end ... but as mentioned, may not be able to let it get to top speed .... as doing 50mph in the bay when there is rough water & a wind would be too risky. Will be able to get WOT though.

 

[emilsr]

Re: Prop choice

What is the diameter of your current prop? That'll help determine which size high-5 that you need. It's a fairly small diameter prop at 13 1/4"....more of a bass boat prop, but some folks like them for towsports on small runabouts. I tried one on a 20' runabout and didn't particularly care for it, but every boat/situation is different and if you liked it before you'll probably like it again.

Squire's suggestion of a Rev 4 is also a good option; the extra inch+ of diameter will give you a little more "oomph" down low without the stern lifting properties of the High 5. The downside to that is a slightly higher minimum planing speed, but bigger wake for boarding and it'll be easier to maintain low boarding speeds. Just another one to think about/try.....maybe both is the answer (one for ski, the other for boarding).

 

[Tafflad]

Re: Prop choice

OK .. putting a tape on it, measures 14"
If anybody knows how to read pn it is stamped as 834654A45P20

Don't want to have 2 props.
A little more ooomph is good, as is maintaining low planning speeds.
Not after any increase in top end.

The idea of Rev4 sounds interesting .. I thought they were only for High speed application ...

as these are only in 'odd number pitch' I would have to go to 19" or 21"

Guess - it will have to wait until I get WOT & speed readings on weekend

 

[emilsr]

Re: Prop choice

Based on the info provided, 19p in a high 5.....assuming you're in the correct rev range right now (which I don't see that we've established).

 

[rallyart]

Re: Prop choice

I tried the High-5 and the Vensura, a a couple others, on my 18' with 170hp. The Vensura was the best for my boat, easily. Adjusting the vent size improved my hole shot and my top speed was the same as with my old 3 blade SS.

 

[Squire]

Re: Prop choice

Based on the info provided, 19p in a high 5.....assuming you're in the correct rev range right now (which I don't see that we've established).

Or a Rev 4 I admit I have no experience with the High 5 but I am very impressed with my Rev 4 and the improvements I gained over the Vengeance I started out with.

 

[Tafflad]

Re: Prop choice

OK did a number of test runs .... average figures ... 2 people on board, 3/4 tank fuel
4 blade 14 x 20" Aluminium prop.
4.3L MPI with Alpha drive 1:62

engine trimmed in ...
4000 WOT 38 mph

Then with engine trimmed partly out ...
4400 WOT 43 mph

As conditions not perfect, did not trim out any further.. a question here when people ask for WOT figures, are these trimmed in or trimmed out ?

BTW .. really neat smart phone app .. "Speedview" has multiple view options & compass ... and like most Android Apps it's free.

Interestingly boat Speedo was almost spot-on, thought it would have been inaccurate.

 

[callen369]

Re: Prop choice

Sounds like you need to drop a couple inches of Pitch. Unless you have another maint issue, those RPM's need to be Ballpark 4800. Think max on mine is 4800, MPI's maybe higher, you'll have to double check. I would have guessed that prop would have been pretty close to on the money. You are running a 4.3 MPI, 220 ish horsepower.... I think your gear ratio is different than mine...Think I am running a 1.81....but mine is carb'd and only 190 rated. If everything else is good, I would try dropping to at least a 19, if not 18 pitch. Man, if you drop pitch to raise RPM, you may loose speed....if we had the same gear ratio, I would be better prepared, Maybe someone else can chime in, but maybe the 1:62 is more for towing, hence lower top speed, better hole shot...If that's the case, a 19 would get you closer to the RPM's you want, and wouldn't sacrifice much top end if any. If you are not into towing, and prefer speed, you may need to check with guys on here about changing your ratio.

As far as WOT, I can't guarantee, but most guys list a top speed along with it, so I will say trimmed out top speed is what you should be looking at.

I was surprised by my speedo as well, mine is a 96 with OE everything, and it matched my GPS as well. Now if I could keep it from clogging all the time....BTW, mine runs 4800 RPM trimmed out at 48/49 MPH.

 

[steelespike]

Re: Prop choice

A wot test needs to be all out settled out to maximum trim. Unfortunately your conditions don't allow.
So we don't have an accurate maximum wot rpm. If you feel it would approach 4800 in calmer conditions your probably ok with the present prop. If you want more jump and to stay on plane easier at reduced throttle maybe drop an inch or 2.But you will lose some top end but with the rough conditions maybe it would be easier to maintain reduced speed.

 

[Tafflad]

Re: Prop choice

If I get a calmer day next week I'll try again ... I think it will get me higher revs by trimming out further ... but unsure if it will be 4800

as this is a 20" pitch ... form what I see most SS at on odd pitch size .. so I could drop to 19"
I'll try to get test done first

 

[Tafflad]

Re: Prop choice

OK ... full throttle and trimmed out to just before cavitation ..
4800 rpm and 44 mph

Back to original Q ... what SS prop should I look at - wake, kneeboard, ski, hydrofoil .... all recreational only inshore salt water.

Getting on plane at lower speeds & staying on plane would be goal rather than top end .... 90% of use is 20 - 25mph