mgg wrote:


I'm not sure that's entirely accurate from my own experience. I had a
aluminum 19 on my 190hp Merc and it ran WOT at about 5400RPM (when I bought
the boat). The manual states 4400-4800rpm for WOT.

I read and heard that the adjustment was (rule of thumb) 1" pitch/200 rpms.
So I increased the pitch to 23 with a SS prop, and I'll be damned if WOT is
at about 4600rpm now...perfect. Maybe it would have been different if I
stayed with aluminum, I don't know. YMMV

--Mike

That's a pretty fast 190 hp. 55 mph?

What hull is that Merc in?

Rob

That's a pretty fast 190 hp. 55 mph?

What hull is that Merc in?

It's a 1995 Reinell 184 BRXL. Let me qualify that MPH statement. The stock
speedo has seen 55 in smooth water and no wind. However, we know how
accurate those things are. I'm going to use a GPS next time out and see what
I really get. Prolly closer to 50. Bottom line really is that WOT is now
within specs with the new prop, and she goes "pretty fast." g

--Mike

"trainfan1" wrote in message
...
mgg wrote:


I'm not sure that's entirely accurate from my own experience. I had a
aluminum 19 on my 190hp Merc and it ran WOT at about 5400RPM (when I
bought the boat). The manual states 4400-4800rpm for WOT.

I read and heard that the adjustment was (rule of thumb) 1" pitch/200
rpms. So I increased the pitch to 23 with a SS prop, and I'll be damned
if WOT is at about 4600rpm now...perfect. Maybe it would have been
different if I stayed with aluminum, I don't know. YMMV

--Mike

That's a pretty fast 190 hp. 55 mph?

What hull is that Merc in?

Rob

mgg wrote:

That's a pretty fast 190 hp. 55 mph?


What hull is that Merc in?

It's a 1995 Reinell 184 BRXL. Let me qualify that MPH statement. The stock
speedo has seen 55 in smooth water and no wind. However, we know how
accurate those things are. I'm going to use a GPS next time out and see what
I really get. Prolly closer to 50. Bottom line really is that WOT is now
within specs with the new prop, and she goes "pretty fast." g

--Mike

If you are running the 1.65:1 gearset, I think you'll find you're
pushing 54-55 if your tach is right.

Rob

On Thu, 31 Mar 2005 21:23:59 -0500, trainfan1
wrote:

If you are running the 1.65:1 gearset, I think you'll find you're
pushing 54-55 if your tach is right.

================================

Assuming 10% prop slip, that's what I calculate also.

51 mph at 15 % , and 48 mph at 20%.

Assuming 10% prop slip, that's what I calculate also.

51 mph at 15 % , and 48 mph at 20%.

Would a SS prop reduce slip?

--Mike

"Wayne.B" wrote in message
...
On Thu, 31 Mar 2005 21:23:59 -0500, trainfan1
wrote:

If you are running the 1.65:1 gearset, I think you'll find you're
pushing 54-55 if your tach is right.

================================

Assuming 10% prop slip, that's what I calculate also.

51 mph at 15 % , and 48 mph at 20%.

On Fri, 01 Apr 2005 06:12:07 GMT, "mgg" wrote:

Assuming 10% prop slip, that's what I calculate also.

51 mph at 15 % , and 48 mph at 20%.

Would a SS prop reduce slip?

=================================

It's hard to say, but it might. The advantages of stainless over
aluminum are structural rigidity (less flex) and surface smoothness
(less friction). Improving either quality could decrease slip which
would have the effect of increasing speed at comparable RPMs.

On Fri, 01 Apr 2005 07:55:30 -0500, Wayne.B
wrote:

On Fri, 01 Apr 2005 06:12:07 GMT, "mgg" wrote:

Assuming 10% prop slip, that's what I calculate also.

51 mph at 15 % , and 48 mph at 20%.

Would a SS prop reduce slip?

=================================

It's hard to say, but it might. The advantages of stainless over
aluminum are structural rigidity (less flex) and surface smoothness
(less friction). Improving either quality could decrease slip which
would have the effect of increasing speed at comparable RPMs.

I wonder if powder coating a aluminum prop would improve the way an
aluminum prop works?

Later,

Tom

"Wayne.B" wrote in message
...
It's hard to say, but it might. The advantages of stainless over
aluminum are structural rigidity (less flex) and surface smoothness
(less friction).

Are you sure? Methinks cast aluminum may be stiffer than steel, as it will
break, as opposed to bending like steel.

Just thinking out load.


--
-Netsock

"It's just about going fast...that's all..."
http://home.columbus.rr.com/ckg/

Wayne.B wrote:


Would a SS prop reduce slip?


=================================

It's hard to say, but it might. The advantages of stainless over
aluminum are structural rigidity (less flex) and surface smoothness
(less friction). Improving either quality could decrease slip which
would have the effect of increasing speed at comparable RPMs.


Steel gets the job done with thinner blades, less interference with the
water. More complex designs & pronounced cupping for a given blade
thickness are possible in steel. We have used the OMC SST II props on
our boats since 1986. They're powder coated steel. The polished props
do look pretty!

Rob

Great info from all of you guys! Thanks.

--Mike


"Wayne.B" wrote in message
...
On Fri, 01 Apr 2005 06:12:07 GMT, "mgg" wrote:

Assuming 10% prop slip, that's what I calculate also.

51 mph at 15 % , and 48 mph at 20%.

Would a SS prop reduce slip?

=================================

It's hard to say, but it might. The advantages of stainless over
aluminum are structural rigidity (less flex) and surface smoothness
(less friction). Improving either quality could decrease slip which
would have the effect of increasing speed at comparable RPMs.