17 Sep 2003 16:19:09
nickthelegend4000
props

Looking for anyone w experience in prop selection. I know many out
there will and have a lot to say about it. We bought a MC 209 SD last
year. From now on, we will be running in deep water lakes. Wondering
what your experiences are on SS props, and the new OJ revolution xmp
if you have tried it. Wondering "how" it may boost the
performance/skiability of a boat even further.

This would be a prime opportunity for another boat opinion war in
here. Not looking at starting a debate on boats, we like what we
have. Please keep it to the prop issue if you don't mind. This is my
first inboard so bear with me please. By the way, I'd never go back
to an IO. Inboard spoil you.

Thanks for all of your input,

nick


18 Sep 2003 20:57:40
Bocİ
Re: props


"nickthelegend4000" <nranson@iupui.edu > wrote in message
news:f91fd8a1.0309171519.56519caa@posting.google.com...
> Looking for anyone w experience in prop selection. I know many out
> there will and have a lot to say about it. We bought a MC 209 SD last
> year. From now on, we will be running in deep water lakes. Wondering
> what your experiences are on SS props, and the new OJ revolution xmp
> if you have tried it. Wondering "how" it may boost the
> performance/skiability of a boat even further.
>
> This would be a prime opportunity for another boat opinion war in
> here. Not looking at starting a debate on boats, we like what we
> have. Please keep it to the prop issue if you don't mind. This is my
> first inboard so bear with me please. By the way, I'd never go back
> to an IO. Inboard spoil you.
>
> Thanks for all of your input,
>
> nick

All I can suggest is to find out what the cam on your boat is rated to -
( RPM's) Find a prop guy - tell him what you want from your boat i.e. more
top end speed - or bottom end grunt - More RPM's when running ( maybe for
barefooting) ect

Then ask if you can test drive a few different props - Props are like cars
you really should drive them before you buy.

Once you have found one that suits you - then buy it. ( In Australia we pay
about $350 - $400 new or $150 S/h)

I am still going through my selection at the moment - I have rebuild my 350
chev including a cam rated to 6500 RPM( dont htink you want to know all the
specs so i wont bore you ) - Put on a brand new 650 4 barrel Holley double
pumper with manual secondaries and running a 3 blade Prop with 14" Pitch (
also going through jet changes in the carb) My boat is quick and can pull 2
skiers out of the deep with little effort yet still not hitting the higher
revs.(Can barefoot with spare rpms) So will be chaging to a smaller prop
soon for a test run.

A guy I know who races boats used cars as an analogy for his explanation -
That was props are like car gear boxes - you can have the most powerfull
engine but with incorrect gearing that car will just not go.

Props are the same - if they try to grab too much water they will not rev
out and you will not be able to get Optimal performance form your motor.

Good luck in your quest -

Boc





18 Sep 2003 10:24:49
Trainfan1
Re: props

> A guy I know who races boats used cars as an analogy for his explanation -
> That was props are like car gear boxes - you can have the most powerfull
> engine but with incorrect gearing that car will just not go.

Boc,

Using your car/boat analogy, you may want to look into a vacuum secondary
carb in the 600 cfm range. A ski boat is analogous to a heavy, full-size
car with a stock converter automatic tranny... definately a vacuum
secodaries, heavy spring, application. You want the engine to demand more
carb, you don't want to force it more than it can take. A big-block 18'
flattie drag boat is more like a stick shift bracket racer - much quicker
rpm gain and ability to take the big gulp of air and all that fuel.

Using volumetric calculations (ask your boat racing buddy), it is unlikley
that a 350 cid engine will ever demand the entire 600cfm under 8000 rpm.
With your 650 and mechanical secodaries in the boat, and a 14" prop, your
intake velocity is falling off. Your asking the engine to give 8000 rpm
with those barrels wide open, which it might with an 8" or 9" prop, but the
boat would be largely usless and rather annoying in this configuration.

Rob
*
*
*

"Bocİ" <Boc@i_farted.com > wrote in message
news:Bcgab.3821$vQ1.190274@nnrp1.ozemail.com.au...
>
> "nickthelegend4000" <nranson@iupui.edu> wrote in message
> news:f91fd8a1.0309171519.56519caa@posting.google.com...
> > Looking for anyone w experience in prop selection. I know many out
> > there will and have a lot to say about it. We bought a MC 209 SD last
> > year. From now on, we will be running in deep water lakes. Wondering
> > what your experiences are on SS props, and the new OJ revolution xmp
> > if you have tried it. Wondering "how" it may boost the
> > performance/skiability of a boat even further.
> >
> > This would be a prime opportunity for another boat opinion war in
> > here. Not looking at starting a debate on boats, we like what we
> > have. Please keep it to the prop issue if you don't mind. This is my
> > first inboard so bear with me please. By the way, I'd never go back
> > to an IO. Inboard spoil you.
> >
> > Thanks for all of your input,
> >
> > nick
>
> All I can suggest is to find out what the cam on your boat is rated to -
> ( RPM's) Find a prop guy - tell him what you want from your boat i.e.
more
> top end speed - or bottom end grunt - More RPM's when running ( maybe for
> barefooting) ect
>
> Then ask if you can test drive a few different props - Props are like
cars
> you really should drive them before you buy.
>
> Once you have found one that suits you - then buy it. ( In Australia we
pay
> about $350 - $400 new or $150 S/h)
>
> I am still going through my selection at the moment - I have rebuild my
350
> chev including a cam rated to 6500 RPM( dont htink you want to know all
the
> specs so i wont bore you ) - Put on a brand new 650 4 barrel Holley double
> pumper with manual secondaries and running a 3 blade Prop with 14" Pitch (
> also going through jet changes in the carb) My boat is quick and can pull
2
> skiers out of the deep with little effort yet still not hitting the higher
> revs.(Can barefoot with spare rpms) So will be chaging to a smaller prop
> soon for a test run.
>
> A guy I know who races boats used cars as an analogy for his explanation -
> That was props are like car gear boxes - you can have the most powerfull
> engine but with incorrect gearing that car will just not go.
>
> Props are the same - if they try to grab too much water they will not rev
> out and you will not be able to get Optimal performance form your motor.
>
> Good luck in your quest -
>
> Boc
>
>
>




18 Sep 2003 17:55:29
Robert Scibienski
Re: props

Go to the source. Talk to Eric at Johnson Propeller.




On 17 Sep 2003 16:19:09 -0700, nranson@iupui.edu (nickthelegend4000)
wrote:

>Looking for anyone w experience in prop selection. I know many out
>there will and have a lot to say about it. We bought a MC 209 SD last
>year. From now on, we will be running in deep water lakes. Wondering
>what your experiences are on SS props, and the new OJ revolution xmp
>if you have tried it. Wondering "how" it may boost the
>performance/skiability of a boat even further.
>
>This would be a prime opportunity for another boat opinion war in
>here. Not looking at starting a debate on boats, we like what we
>have. Please keep it to the prop issue if you don't mind. This is my
>first inboard so bear with me please. By the way, I'd never go back
>to an IO. Inboard spoil you.
>
>Thanks for all of your input,
>
>nick



19 Sep 2003 09:44:41
HWallaceii
Re: props

Nick,
Tell us more: Engine? Trans? What will you use it for?

Ham Wallace


20 Sep 2003 06:28:36
Pat Sproule
Re: props

Boc, try one of the 4 blades as well. Made a huge difference to our Hallett
(tried it as well as some 3 blades). We got ours through DH Porter in
Sydney.

Pat.


"Bocİ" <Boc@i_farted.com > wrote in message
news:Bcgab.3821$vQ1.190274@nnrp1.ozemail.com.au...
>
> "nickthelegend4000" <nranson@iupui.edu> wrote in message
> news:f91fd8a1.0309171519.56519caa@posting.google.com...
> > Looking for anyone w experience in prop selection. I know many out
> > there will and have a lot to say about it. We bought a MC 209 SD last
> > year. From now on, we will be running in deep water lakes. Wondering
> > what your experiences are on SS props, and the new OJ revolution xmp
> > if you have tried it. Wondering "how" it may boost the
> > performance/skiability of a boat even further.
> >
> > This would be a prime opportunity for another boat opinion war in
> > here. Not looking at starting a debate on boats, we like what we
> > have. Please keep it to the prop issue if you don't mind. This is my
> > first inboard so bear with me please. By the way, I'd never go back
> > to an IO. Inboard spoil you.
> >
> > Thanks for all of your input,
> >
> > nick
>
> All I can suggest is to find out what the cam on your boat is rated to -
> ( RPM's) Find a prop guy - tell him what you want from your boat i.e.
more
> top end speed - or bottom end grunt - More RPM's when running ( maybe for
> barefooting) ect
>
> Then ask if you can test drive a few different props - Props are like
cars
> you really should drive them before you buy.
>
> Once you have found one that suits you - then buy it. ( In Australia we
pay
> about $350 - $400 new or $150 S/h)
>
> I am still going through my selection at the moment - I have rebuild my
350
> chev including a cam rated to 6500 RPM( dont htink you want to know all
the
> specs so i wont bore you ) - Put on a brand new 650 4 barrel Holley double
> pumper with manual secondaries and running a 3 blade Prop with 14" Pitch (
> also going through jet changes in the carb) My boat is quick and can pull
2
> skiers out of the deep with little effort yet still not hitting the higher
> revs.(Can barefoot with spare rpms) So will be chaging to a smaller prop
> soon for a test run.
>
> A guy I know who races boats used cars as an analogy for his explanation -
> That was props are like car gear boxes - you can have the most powerfull
> engine but with incorrect gearing that car will just not go.
>
> Props are the same - if they try to grab too much water they will not rev
> out and you will not be able to get Optimal performance form your motor.
>
> Good luck in your quest -
>
> Boc
>
>
>




21 Sep 2003 08:51:42
Bocİ
Re: props


"Pat Sproule" <patsproule@ozemail.com.au > wrote in message
news:MGJab.4120$vQ1.206323@nnrp1.ozemail.com.au...
> Boc, try one of the 4 blades as well. Made a huge difference to our
Hallett
> (tried it as well as some 3 blades). We got ours through DH Porter in
> Sydney.
>
> Pat.


Ok was actually going to ask that -------- I have the 14" 3 blade on now
( brass Austral ) what would you suggest to go to in regards to pitch for
ther 4 blade or even a smaller 3 blade?

on another note - i have to lift the motor today and take of the sump ( 350
chev) sigh -- it has developed a leak and suspect a small rust hole :(


Boc





21 Sep 2003 09:22:31
nickthelegend4000
Re: props

Ham,

I have 330hp engine, standard 1:1 trans. We slolom and wakeboard. I
had heard that some props(SS) can make a big difference in wake,
vibration, etc. We will continue to do the same standard activities w
the boat. Standard 4 blade prop that is on it needs a "touch up" and
would like to buy another as a spare or main prop if it will give me
better performance. Hope this helps.

nick

hwallaceii@aol.com (HWallaceii) wrote in message news:<20030919054441.08204.00001096@mb-m14.aol.com >...
> Nick,
> Tell us more: Engine? Trans? What will you use it for?
>
> Ham Wallace


22 Sep 2003 13:38:44
Pat Sproule
Re: props

We went from a 12x15 3 blade Moritz to an 11x14 4 blade Austral (general
rule of thumb is to take an inch off when going to the 4 blade. I lost about
3 or 4 mph off the top speed but picked up heaps of tow down low. Peak revs
are 5000 with an indicated 50mph. This is a fairly light weight 18ft boat
with a reasonable stock 350 running a soft clutch.

The big difference was that when standing on the throttle the motor can
literally jump straight to about 2800rpm which is right in the meat of the
power band. Before it used to bog at around 2000 and take a while to climb
onto the torque curve. This is great for dragging out several slaloms or
barefooters, or even disposing of the passenger to the back seat.

You should be able to ring someone like Porter, and based on the details of
the hull, motor and it's intended use, they will suggest a prop that is
fairly close. I prefer using them over the local marine shop based on their
specialised knowledge of an otherwise black art.

Make sure you read up about driveshaft alignment if you are going to pull
the motor. It's a bit of a fiddly process to get it right when you put it
back in.

Pat.


"Bocİ" <Boc@i_farted.com > wrote in message
news:1S4bb.4348$vQ1.218049@nnrp1.ozemail.com.au...
>
> "Pat Sproule" <patsproule@ozemail.com.au> wrote in message
> news:MGJab.4120$vQ1.206323@nnrp1.ozemail.com.au...
> > Boc, try one of the 4 blades as well. Made a huge difference to our
> Hallett
> > (tried it as well as some 3 blades). We got ours through DH Porter in
> > Sydney.
> >
> > Pat.
>
>
> Ok was actually going to ask that -------- I have the 14" 3 blade on now
> ( brass Austral ) what would you suggest to go to in regards to pitch for
> ther 4 blade or even a smaller 3 blade?
>
> on another note - i have to lift the motor today and take of the sump (
350
> chev) sigh -- it has developed a leak and suspect a small rust hole :(
>
>
> Boc
>
>
>