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Martec Prop Usage

K2MSmith

Sustaining Member
I have a Martec prop which the previous owner had cleaned/refurbished not too long before I purchased the boat. See photo. I believe it would be the 2-blade "elliptical" type. (not sure of the exact "mark" number).

From the Martec site, there it not that much information on use. I am wondering if I should keep the boat "in gear" when the motor is off when I am sailing (either in "forward" or "reverse" as opposed to "neutral" ?). Is there anything I should do to facilitate opening/unfolding the prop when going into reverse ? I realize that the prop opens by centrifugal force so perhaps it doesn't matter, but I do notice some shaft vibration in reverse that I don't notice in forward gear - but maybe a characteristic of these props (?).

There are a note on the Martec site under "Racing":

"Manually rotate the shaft to the best sailing position, where the previously marked pivot pin is vertical"

My prop shaft doesn't appear to be easily accessible, but I'll have to check to see if this is marked. I assume you would have to do this rotation when the transmission is in "neutral".
 

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Marlin Prowell

E34 - Bellingham, WA
The Martec blades pivot independently, so the lower blade can drop down while the other blade feathers. Other folding props, like the Flexofold, are geared, so if one blade wants to feather, the other blade will, too.

Note that the note is under the Racing section. When I crewed when racing on a boat with a Martec prop, I had to go below and observe the prop shaft while the skipper would tap the start button to slightly turn the prop shaft. The goal was to align the prop shaft as Martec describes, with the hinge pin vertical. I’d call out when the shaft was oriented correctly. Did it make a difference in a race? I doubt it. Any slight mistake during the race would cost more than a droopy prop blade, but it made the skipper happy.

I think the issue of keeping the transmission in neutral or in gear depends on the transmission. Hurth ZF transmissions (for example) must not be in forward while sailing with fixed props. Technodrive Twin Disc transmissions don’t seem to care as much. Check your transmission manual for details.
 

Navman

Member III
I keep mine in neutral when the engine is off and sailing. Sometimes you can here a slight noise.A droopy blade I suppose. That's when I put the gear in reverse and then back to neutral and the noise goes away. By doing that I guess it allows the water flow to better align the blade to the flow. Works for me. I do love my Martek prop except when I am in adverse conditions and need more umph. That's when I wished I had a three blade feathering or folding prop.
 

Phil MacFarlane

Member III
When shifting from neutral to either forward or reverse make sure the engine is at minimum rpm. When you are ready to shut off the motor and sail, pop it into reverse just for moment this will help fold the blades then put it in neutral. The reason it vibrates in revers is, as stated above the blades are independent of one another and at low rpm in reverse they want to close somewhat this can lead to an imbalance which should go away with higher rpm.
 

frick

Member III
I used to have a sharpie mark on my prop shaft, and I would pop down and turn it by hand to align the pin vertically. To be honest, I don't do that now unless I hear from noise from the prop.... I have sailed with Martek props for decades
 

markalan

Member II
I took off a brand new 3 blade prop that came with the Olson 34 and replaced with the 2 blade Martec racing prop. I simply painted some white out on the top of the shaft when aligned. When racing or wanting to sail faster I set the prop and regardless always put in reverse. If I leave in neutral the shaft will start turning when under weigh.
 

Phil MacFarlane

Member III
I took off a brand new 3 blade prop that came with the Olson 34 and replaced with the 2 blade Martec racing prop. I simply painted some white out on the top of the shaft when aligned. When racing or wanting to sail faster I set the prop and regardless always put in reverse. If I leave in neutral the shaft will start turning when under weigh.

Good move to the Martec. If it turns in neutral it's not folded, at least all the way.
 
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