GL: Props

[fred]

Ken,

Prop selection ought to bring a pretty large selection of diverse
opinions.

Generally, the "correct" prop is the one that allows the engine
to run full throttle right at the RPM redline.  

However, I noticed that on
my particular boat, the engine options were a 330 HP or a 370 HP engine.
Oddly the larger engine delivered better fuel mileage at slow speeds.  Talking
to the manufacturer, they told me the larger engine turns a prop with greater
pitch.

So, I'd say if the props you were using gave you redline RPM at full
throttle, you might go to the next higher pitch, and get improved fuel mileage
at trawler speeds.  Though it will cost you by reducing your top speed.

If
your boat has a small engine and is normally only good for 8 or 10 knots, then
stick with what ya got.

Switching to a different prop manufacturer might
give you a prop that is cupped a bit more and that might improve performance,
but you pay for that also with very sluggish backing up performance.
Whatever you do, go with very small changes.

Lastly, get the props tuned
exactly, look into the MRI system which uses a laser to exactly measure the
blades.  MRI costs about 450 bucks a prop.

Fred
Tug 44
----------------------------------------
From: "Ken Tucknott"
<katuck214 at mchsi.com>
Sent: Sunday, November 02, 2008 5:08 PM
To: "Great
Loop" <great-loop at lists.samurai.com>
Subject: GL: Props 

Hello all,
Once again I could use some direction from the list.  I am going to replace my
props next spring, using the existing ones as back ups.  I am not  'married'
to any type or manufacturer, and I will view all comments as positive.  Not
exactly sure of the size, I do believe they are 22x18.  Any additional info
needed please let me know.  Boat will be cruising at a slow leisure pace while
doing the Loop.  Fuel consumption is more important than speed.

Thanks to
all in advance.

Ken Tucknott
Trista Gray
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