mac 19 propeller pitch question
- re: Incidentally to the group -, my '93 Mac 19 has been "in dry
dock" (on the trailer in the back yard) awaiting my finishing some
modifications for going on two years. The biggest one being
installation of a 2 stroke Merc. 50 and EZStick steering and the
fiberglass work of waterproofing the holes made in the motor well
when the steering went in. If you've a 50hp too, can you please tell
me what prop pitch works best and what speeds you top out at?
I got my mac 19 with an almost new looking Tohatsu m40c ( 2 stroke )
with a 10 pitch 3 blade fairlu dinged up prop. It seemed to move the
the boat well with the tank empty, ( sorry no speedo ) but really
struggled to get up on a plane with the tank full.
I got this chart ( I'm sure your 2 stroke has similar rpm )
and ordered the 7.1 pitch 4 blade prop ( the one for the heaviest
load ) and the difference was ammazing. It planes with a full tank no
problem, and it "felt" much faster with the tank empty. Worth noting
is that with this prop the motor mount/transom "creak" a little going
from dead slow to faster. A little unnerving. I have video on youtube
of my mac with this prop tank empty on a flat day.
I have a digital windspeed meter, so I'll try and get a ball park top
speed. Macgregor says 25mph ( with an empty boat 1 person and no mast
attached and no extra wieght) So I bet the top speed is less for my
boat with 2 batteries, 2 gas tanks, anchor/chain etc.
I also picked up a brand new "hustler" 3 blade 8 pitch prop for 40
bucks on ebay and will give that a try soon if I get the chance.
I assume it will be a little faster with the tank empty and slower
with the tank full.
I keep the tank full with my wife and 2 kids aboard mostly, but I'll
empty it if I'm by myself and want to freak out the local "yachties"
by blasting by.
I really hate the noise of the 2 stroke 40 at full speed...And also
the limited steering of the side mounted tillar. ( no right turns
I'd like to get a 4 stroke 50 hp honda or suzuki ( with a center
mounted tiller ) but they cost too damn much. 7 to 10 grand!!