"Dave Jones" wrote in message
...
I just re-proped my boat -- my range is supposed to be 4200-4600

is this under "best case" conditions? (flat water, no wind, light load,
trim
optimised, etc)

Or "no mater what, when you're "WOT" your engine should be between
4200-4600?

Thanks
Davie

It should be optimized for your normal loading and usage and depends a lot
on the size of your boat. That RPM range indicates a likely I/O setup and I
assume it's a single engine. You may find out, as I did years ago, that you
will have two props ... one for normal use with 2 or 3 people aboard and a
second, lower pitched prop for when the whole gang shows up for a boat ride.

RCE

www.eisboch.com

RCE wrote:
"Dave Jones" wrote in message
...

I just re-proped my boat -- my range is supposed to be 4200-4600

is this under "best case" conditions? (flat water, no wind, light load,
trim
optimised, etc)

Or "no mater what, when you're "WOT" your engine should be between
4200-4600?

Thanks
Davie


It should be optimized for your normal loading and usage and depends a lot
on the size of your boat. That RPM range indicates a likely I/O setup and I
assume it's a single engine. You may find out, as I did years ago, that you
will have two props ... one for normal use with 2 or 3 people aboard and a
second, lower pitched prop for when the whole gang shows up for a boat ride.

RCE

www.eisboch.com



Excellent advice. For my Evinrude 115(16' Glastron), I have a SS 19"
prop that is good for overall use, a SS 17" prop for heavy loads w/
watersports & gear for a day away from the dock, and a large surface
area AL 15" prop for power on demand (we sometimes pull 5 skiers with
this prop) but even with 5 skiers in tow, the engine will over-rev at
full throttle once they are up.

Our old inboard is getting tired, I have 2 14", a 15", a 10" & a 9"
NiBrAl (or brass) props for it, it likes the 14" cupped Michigan the
best at 4600-4800 rpm(engine is rated 220hp at 4400) . It over revs
with the 14" Stannus, to almost 5000 rpm, this we do only for short
bursts with a good load in the boat.

I/O & inboard engines(& most outboards - some Mercs are VERY sensitive
to this) really should not be run for any duration over recommended WOT max.

Target the middle of the range with your usual load.

Rob

"RCE" wrote in message
...

"Dave Jones" wrote in message
...
I just re-proped my boat -- my range is supposed to be 4200-4600

is this under "best case" conditions? (flat water, no wind, light load,
trim
optimised, etc)

Or "no mater what, when you're "WOT" your engine should be between
4200-4600?

Thanks
Davie

It should be optimized for your normal loading and usage and depends a lot
on the size of your boat. That RPM range indicates a likely I/O setup and
I assume it's a single engine. You may find out, as I did years ago, that
you will have two props ... one for normal use with 2 or 3 people aboard
and a second, lower pitched prop for when the whole gang shows up for a
boat ride.

RCE

www.eisboch.com


Are you telling us that you actually changed props each time your guest list
changed?

"Bryan" wrote in message
. com...

"RCE" wrote in message
...

"Dave Jones" wrote in message
...
I just re-proped my boat -- my range is supposed to be 4200-4600

is this under "best case" conditions? (flat water, no wind, light load,
trim
optimised, etc)

Or "no mater what, when you're "WOT" your engine should be between
4200-4600?

Thanks
Davie

It should be optimized for your normal loading and usage and depends a
lot on the size of your boat. That RPM range indicates a likely I/O
setup and I assume it's a single engine. You may find out, as I did
years ago, that you will have two props ... one for normal use with 2 or
3 people aboard and a second, lower pitched prop for when the whole gang
shows up for a boat ride.

RCE

www.eisboch.com


Are you telling us that you actually changed props each time your guest
list changed?


No. Not every time. Most of the time there was only one or two people on
the boat and I had a 14 pitch prop. Once in a while, if I knew we were
going to have four or five people on the boat for an outing, I'd change it
to a 12 pitch. The 12 was originally an 11 that I had re-pitched after
experimenting. This boat was an older (1982) Century 7000 Express that was
heavy and underpowered with the 260 hp GM 350 engine. It was stern heavy and
struggled to get up on plane with more than 3 people on board.

Changing the prop was a 5 minute job, even when the boat was in the slip.

RCE

www.eisboch.com

"RCE" wrote in message
...

"Bryan" wrote in message
. com...

"RCE" wrote in message
...

"Dave Jones" wrote in message
...
I just re-proped my boat -- my range is supposed to be 4200-4600

is this under "best case" conditions? (flat water, no wind, light load,
trim
optimised, etc)

Or "no mater what, when you're "WOT" your engine should be between
4200-4600?

Thanks
Davie

It should be optimized for your normal loading and usage and depends a
lot on the size of your boat. That RPM range indicates a likely I/O
setup and I assume it's a single engine. You may find out, as I did
years ago, that you will have two props ... one for normal use with 2 or
3 people aboard and a second, lower pitched prop for when the whole gang
shows up for a boat ride.

RCE

www.eisboch.com


Are you telling us that you actually changed props each time your guest
list changed?


No. Not every time. Most of the time there was only one or two people on
the boat and I had a 14 pitch prop. Once in a while, if I knew we were
going to have four or five people on the boat for an outing, I'd change it
to a 12 pitch. The 12 was originally an 11 that I had re-pitched after
experimenting. This boat was an older (1982) Century 7000 Express that
was heavy and underpowered with the 260 hp GM 350 engine. It was stern
heavy and struggled to get up on plane with more than 3 people on board.

Changing the prop was a 5 minute job, even when the boat was in the slip.

RCE

www.eisboch.com

This alternating prop, so to speak, idea is intriguing. I've been wondering
how to deal with the variability of having me and 4 12-year old girls on the
boat or two families with large adults. If the prop change for my boat is a
minute job once I decide which prop to carry as my alternate ...