What are Catalina 320 owners opinions of the three bladed versus two bladed propellers supplied by Catalina as standard equipment?
I have a 2-bladed propeller on
Ray Harris, Aurora Hull, C320 #102
I bought my 320 this spring, upgrading from a C30. My opinion is the three bladed propeller is really a no brainer. The difference in control, (especially in reverse and turning in tight quarters) is significant and speed while motoring is much better.
Jon Vez, Solstice, C320 #582
Phone: (401) 847-7960
Fax: (401)849-0631
Email: Sales@autoprop.com
Recommended
prop sizes by Engine and Transmission:
Catalina
320
Engine:
Yanmar 3GM30F
Max.
BHP: 27
Max.
RPM 3600
Reduction
Ratio: 2.21:1
Rotation:
Right Hand
Shaft
Diameter: 1”
Autoprop
recommends a propeller size of 16” in diameter.
Max.
BHP: 27
Max.
RPM: 3600
Reduction ratio: 2.47
1" shaft
Right hand
17" Autoprop
Many Catalina 320 owners
opt to replace the standard
We
have the 16" Autoprop on the Yanmar.
For those of you still using the fixed blade propellers from Catalina,
you don't know what you're missing, a good 1+ knot gain while motoring and a
sound .5 to 1 knot gain while sailing plus improved steering while sailing due
to less turbulence on the rudder. The best single investment we made to
improving the 320.
Jim Carlsen, Wine and Roses,
C320 #573
Both propellers are pretty
good. The Max-Prop has a SLIGHT advantage while sailing, something on the order
of 2 or 3 percent efficiency. But the Autoprop is a much better motoring
propeller, probably better than anything on the market. The tests in Practical Sailor just about put it into
it’s own class.
The automatically
adjusting pitch and 360 degree blade rotation are what makes the difference.
Propellers are really a compromise, what works at low speed for pulling power
does not work at higher speeds for cruising. It’s similar to a car with 4 or 5
forward speeds. Different pitches would be more efficient. Same for reverse -
the trailing edge becomes the leading edge on a fixed blade and suffers. The
Max-Prop does turn partially around so the leading edge still leads, but the
other side of the blade does the pushing - hence the flat and less efficient
blade. The blades on the Autoprop are always going forward and always at the
most efficient pitch, even in reverse. This extra bite in reverse is what virtually
eliminates propeller walk on the Autoprop.
The angle of the blades is dependent on shaft speed, hull speed through
the water, and direction of rotation. It continuously adjusts itself. At zero
shaft speed while moving through the water, the blades point to the rear (an
infinite pitch). But you’ve got to be able to lock the shaft.
In my experience, the
Autoprop is about 25 percent more efficient under power than fixed, folding or
feathering propellers. That’s based on my boat and comparisons with similar
boats with other propellers. That translates to either a higher cruising speed
for a given RPM or decreased fuel consumption. The ability of the propeller to
change pitch really helps in powering directly into heavy weather. It also is
great for motor sailing - the propeller will adjust itself based on the force
supplied by the sails. You probably wind up with a 40 or 50 pitch under these
conditions.
All is not perfect though
- the propeller works better in larger sizes. The hub is somewhat bigger than
the hub on a normal propeller, and the blades are therefore a drop smaller. On
a very small propeller, you’ll wind up with no blades at all. Because of this, they don’t even make one for
smaller boats. The guys there are very honest - give them a call and see if
they even recommend putting one on a 320. If they do, it would be my first
choice.
Windwalker has the Yanmar
3GM30F (27 hp) and the 16” Autoprop. I
calibrated the B@G
knot meter at a measured mile before performing the tests.
There was about 10 knots
of wind in
RPM vs. Observed Knots
|
Engine RPM |
Trial 1
Speed
in Knots |
Trial 2
Speed
in Knots |
Average
Speed, Knots |
|
1000 |
4.0 |
4.0 |
4.0 |
|
1200 |
4.7 |
4.4 |
4.55 |
|
1400 |
5.45 |
5.1 |
5.28 |
|
1600 |
6.0 |
5.6 |
5.8 |
|
1800 |
6.4 |
6.0 |
6.2 |
|
2000 |
6.6 |
6.3 |
6.45 |
|
2200 |
6.9 |
6.7 |
6.8 |
|
2400 |
7.2 |
7.0 |
7.1 |
|
2600 |
7.3 |
7.0 |
7.15 |
|
2800 |
7.35 |
7.2 |
7.28 |
|
2850 (Max) |
7.35 |
7.35 |
7.35 |
Richard A. Walker, Windwalker, C320 #687
The
following commentary was a result of a discussion regarding whether a stainless
steel shaft or a standard bronze shaft was required with the Autoprop.
I may be the one who was talking about a SS shaft with
the Autoprop. Even though I put an SS
shaft on WindSwept, it may not be necessary.
Let me explain.
When I first installed my Autoprop, it was installed by
a diver. I got very severe
vibration. This was with the stock
bronze shaft. I had to have the Autoprop
removed by the diver, who was able to do this without the special puller.
The second installation was done with the boat out of
the water for a.bottom job. At this time
we found the gap between the hub and cutlass bearing was 2-1/4 inches. Autoprop says this should be 1 to 1.5 times
shaft diameter, or 1.5 inches maximum.
The Autoprop people gave me two options.
The preferred option was to pull the shaft and have it shortened. The second, which I went with, was to try a
special hub that Autoprop sent to me which moved the blades forward, closer to
the cutlass bearing. The theory was that this would stop the end of the shaft
from whipping. I had less vibration, but
still an excessive amount. What was
particularly troublesome was that the shaft jumped around enough that it hit
the inside of the shaft log. Not wanting
the inside to become the outside, I had a diver remove the propeller a second
time, again without a special puller.
The third try was nearly two years later when WindSwept
was out of the water for her second bottom job.
This was in November 99. I knew
at this time that I had to pull the shaft and have it cut shorter. This was an expensive job, as the rudder has
to come off, the coupling flange had to come off, the flange end of the shaft
had to be machined after cutting, and I had a PSS shaft seal that also had to
be disassembled. Since I was putting
this much work into it, and Catalina would provide a new SS shaft for $190 plus
shipping, I decided to put in the new shaft to make sure I got it right. I also replaced the cutlass bearing at the
same time.
The result is that I
have very little vibration and the Autoprop is still on. The propeller shaft seems to be rock
steady. There is a little vibration, but
it is more a low frequency pulsation, which I think is coming from the
propeller itself. It is pretty minor
however.
I think my problem comes from a propeller shaft that was
cut too long by Catalina. In one of my
discussions with Catalina they told me that each shaft is cut to length
depending on field measurements. Therefore, I wouldn't expect everyone to have
a similar problem to mine.
By the way, if you try using the bronze shaft, you will
either have the vibration from the start or probably not at all. I would, however closely measure the hub to
cutlass bearing distance, and strongly considering shortening the shaft if this
exceeds 1.5 inches. From what I have
heard of other Autoprop installations on 320s, this has not been a
problem. In fact some have had to
install a drive saver between the shaft flanges, or alternatively machine a bit
of the trailing edge of the strut away to keep the Autoprop blades from hitting
the strut when it reverses direction.
Larry
Frank, WindSwept, C320 #246
2257
Phone
(562) 435-4495
Fax: (562) 435-7846
Email: (martec-props@worldnet.att.net
What are Catalina 320 owner experiences with Martec Folding and
Feathering propellers.
Martec Two Blade Folding
We converted to a Martec folder from the 3 blade that was originally on our boat. I have noticed no appreciable loss of forward speed, 6.9 to7.1 knots at 2800-3000 rpm (Perkins M30). Backing power seems good as we have to back about 200 feet into our slip and can do so without much difficulty. The improvement in sailing speed seems quite significant especially acceleration in light air.
The downside is that any folder or feathering propeller will have more vibration underway than a fixed propeller so if you motor a lot it may get on your nerves a certain rpms. Also there is one heck of a clunk, that takes some getting used to, when the blades open under power.
The quality of the propeller appears excellent and the installation is quite easy. Martec did say that if you do extensive motoring in heavier seas that you may want to jump to the 16x12 but for us that was not necessary.
Dave Ash, C320 #48 Nous
Sommes Ici
We have the Martec two blade on Charmed and it seems to work
well. In light air it definitely moves
the boat faster. It's not perfect
though. It is definitely harder to back
down but not impossible to do, but it takes some practice. I haven't noticed any problems in powering
through chop. It does create more
vibration under power. We are looking
for ways to reduce this and might try a damper between the shaft coupling and the
transmission to reduce this. West Marine
has such a part.
Vin Ratford,
Charmed, C320 #560
Bob Sweeney, Inkling, C320
#129
Martec Two Blade
Feathering
I have had the MARTEC two blade, 16 inch, feathering propeller on
my 320 for three years now and love it.
It gives plenty of power in reverse,
with great control and does show some speed increase under sail in light
wind. This may be a good compromise between the Auto prop and the folding
propeller.
Jim Mills, C320
#209
Martec Three Blade Feathering
One other option is a Martec 3-blade feathering propeller That's
what's on my C42 and it is wonderful. Another BIG feature of feathering
propellers is they motor in reverse almost as well as in forward. I can come to
a complete stop, put it in reverse, and the stern will go to port 3-4 degrees
before I get control again. There's no "cupping" of the blades. With
fixed propellers, they are optimized to go in forward with little regard to
reverse. As you all know, they travel to port nearly 45 degrees before you can
straighten the boat out. (One way to minimize is to do what I did on my C36,
goose it in reverse until it was just about out of control, put it in neutral,
gain control back, goose it in reverse again, you may have enough speed to gain
control then.) Another big advantage of Martec feathering propellers is their
ability to easily change the pitch, independently in forward and in reverse. It
may take a few trips underwater to get just the pitch you want. I set it a year
ago and am still happy with that pitch.
On this list there was discussion about the extra time it takes to
switch from forward to reverse and visa-versa. This is true. It takes less than
one second for the switch. After a little experience, you get to compensate and
it is a non-problem. What's a bigger problem is the need to start the engine in
reverse. I understand with the bigger boats/fixed propellers, if you put the
gear in reverse while sailing, it is nearly impossible to put it in neutral to
start the engine. I've heard the recommendation is to start it in reverse then
switch to neutral. That scares me.
Back to the discussion about applying antifouling paint on folding/feathering propellers. I am no authority on this subject, but had two different people professionally paint the bottom (yup, I had water based paint that lasted 1 year). Both said it is unwise to paint a feathering propeller as they couldn't guarantee to keep ALL paint out of the moving parts. They both refused to paint the propeller That does bring my operating costs up a bit as the bottom can go for several weeks, propeller just a few weeks.
Norm Perron,
Aphrodisiac, C42 #600,
We bought the Martec 3 blade SS feathering propeller and love
it. Pretty pricey but less than the
Autoprop and less drag than the Autoprop.
Backing performance is a dream.
So much better than the fixed 3 blade.
Back straight as an arrow and stop on a dime. It did take almost 40 minutes to install
though.
No extra hardware was needed, no changes to the shaft or bearings.
The speed increase was tremendous.
Especially in the light to moderate air.
Terry W Thomas,
Stern First, C320 #488
Autostream
3-Blade SS Propeller
I installed a Martec 3 blade feathering propeller (16" 10 pitch) on my new C320 (hull # 619) last February. Since I had it installed when the boat was delivered I can't comment on any speed improvements under sail. I am disappointed with the performance when motoring. Previous e-mails on the Martec indicated minimal if any propeller walk. I have significant propeller walk, especially in reverse (pulls to port). At the beginning of season maximum, speed was 7.1 knots @ 3600 RPM which is right on for the Yanmar peak power curve. Past and recent e-mails indicate the Autoprop. achieves the same results at 2900 - 3100 RPM. I must therefore assume the Autoprop is a much more efficient design? Still hard to believe that the horsepower the Yanmar is putting out at 3000 RPM can get the boat to 7 knts.
By Aug. my top speed was only 6.5 knts and I could only get about
3200 RPM out of the engine. In October.
I had the boat hauled and the bottom cleaned.
Lots of barnacles on the propeller which cut down on efficiency. Once cleaned I was able to achieve 7 knts
again but by the end of the season I experienced a different result in that the
engine was now maxing out at 3800 RPM and only 6.8 knts achieved. I assume that somehow the pitch changed and I
must repitch the propeller. Instructions provided by Autostream on how to
adjust the pitch are really poor so I intend on contacting them in the
spring. Should be an easy operation
since there are two adjustment screws for this purpose.
The propeller is an ugly looking thing, but seems to be well
constructed of stainless steel. I think
I paid on the order of $1600 for the propeller plus installation by my dealer.
Since the propeller was on since the boat was new I do not have a before and
after result so hard to say what the improvement really is.
Joe Tamucci, C320 #619
Max-Prop
PYI INC.
Phone: (425) 355-3669
Fax: (425) 355-3661
E-Mail: pyi@pyiinc.com
Here are some owners comments regarding two blade versus three
bladed Max-Props
I had a 3 blade Max-Prop on my TMI 30 (Chrysler) and loved it. Both my forward and reverse performance improved big time over the fixed two blade plus our sailing speed increased .5 knots +. The only thing I had to do installing the propeller myself was to drill the ss shaft for a lock pin. PTI supplies both the pin and the drill bit to do the job. The bit went through the shaft with no problem and all I had to do was trim the pin length with a file. I strongly recommend that you call PYI. They have people there who can answer ALL of your questions. The best recommendation I can make is to say that I plan to install a Max-Prop on our C320, #394. The present fixed 3 blade is terrible in comparison.
Ralph Winkler,
Wind Dancer, C320 #394
I would definitely buy the 3-blade feathering propeller
I had a 2-blade Max-Prop feathering propeller installed on "
I'm not aware of any shaft work that was done when the 2-blade
feathering propeller was installed, and know that no shaft work was necessary
when the 3-blade propeller was installed.
While the 3-blade propeller may produce more drag, I have not
noticed any real difference between the two under sail. In addition, I have not noticed any real
difference leaving the slip or returning to the slip with the 3-blade propeller
versus the 2-blade propeller.
Chris King,