I have a 10 year old Martec elliptical RHDH14P-3 one inch shaft that I replaced
with a Flex-o-fold last year. This was used with Yanmar 3GM30F. It is
From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Rick Brass
Sent: Saturday, February 17, 2018 1:17 AM
Cc: Rick Brass
Subject: Re: Stus-List Help with folding prop insights?
My 38, Imzadi, came with a 16x10 ½ RH Martec prop when I bought her in 2003.
16x10 ½ was the prop recommended for my 15,000lb boat with a 36hp engine and
whatever gear reduction I have. I was quite pleased with the performance. It
would get hull speed (about 7.2 kn) at 2400 RPM and reach 3000 in a pinch. It
took me a month or two to learn the trick to reverse: Hit the throttle high to
unfold the prop (with moderate forward speed and moderate throttle, the flow of
water keeps the prop partly closed... so performance sucks), once the boat is
moving aft fast enough for flow over the rudder you shift into neutral and
steer with the rudder. I've been backing into my slips for 14 years and have
only hit the dock a couple of times. BTW, the prop does give a fair amount of
My prop must have been near the end of its third life, because after a couple
of years one of the "ears" in the hub broke and I had to replace the prop with
a 2 blade fixed prop of the same diameter and pitch. I found that I lost about
½ knot of boat speed when sailing in light to moderate winds.
I bought a used Martec that was 17x10 and had Martec refurb it. I was greatly
over propped, and could barely get to 2000RPM. Also had a vibration because the
prop tips were too close to the bottom of the boat, I think.
I replaced that Martec prop with a Gori geared prop: Their recommended prop is
a 16 ½ x10 was still overpropped because of the blade profile, and frankly,
after 3 years of use, I was more satisfied with the Martec. When I discussed
the overprop situation with them while the boat was being painted last winter,
they said that the 10 pitch was the lowest they had in the 16 ½ diameter, and
going to a smaller diameter would involve getting a whole new propeller. At
their suggestion I had a local shop trim 1/2'" from the tip of each blade. It
is better, but still not as good as the Martec.
You mention that your prop is 18x12, which seems like a lot of prop depending
on your engine max RPM and HP, gear reduction, and boat weight. Before you
spend money on reconditioning the prop, you might want to ask Martec what prop
diameter and pitch they recommend for your boat.
From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Bruce via
Sent: Thursday, February 15, 2018 8:28 PM
Subject: Stus-List Help with folding prop insights?
I have a fixed, 3 bladed prop on Astralis currently, and suspect that its
slowing us down here in Florida where we just don't get the wind like we did on
Lake Michigan, so we rarely see much over 12 kts or so. I'm thinking I'd like
to get a little more speed out of her, and one area of improvement could be the
In the pile of old parts that the prior owner left us, I found an old, and
obviously used Martec Eliptec RH18DX12P-3, two blade folding prop (it is not
geared). I have the blades and hub, but at the moment cannot find the center
pin. It seems like Martec may still be in the business of repairing these
I've read some of the various reviews, and I understand there are better
solutions out there, but clearly I'd be dropping a few boat bucks to pull it
Do any of you have direct experience with the Martec Eliptec, and can advise me
whether I'll hate this thing from a performance or vibration point of view if I
get a pin and put it on the boat?
I am OK with somewhat limited reverse, but would be anxious if I was giving up
a lot of forward power. And, I really don't want a lot of vibration,
especially if it's going to do things like tear up the cutlass bearing.
Thanks for your insights!
Bruce C. Whitmore
1994 C&C 37/40+, "Astralis"
Madeira Beach, FL
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