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Olson 34 New Prop Selection

Cbuydos

Member I
I have made the decision to replace the prop on my Olson 34. The current Martec folding prop (RH 15” d and 12 p) is beyond service at this point. I’m curious to know what the rest of the Olson owners are using based on the engine you have and specs on your prop you are using (size, pitch, brand)?

Thinking about a Gori geared 2 blade as I race. Gori recommended that I go with a 10 pitch with their propeller. Just a bit nervous about the 2 point pitch reduction, though that could be the difference in the old Martec feathering style vs. the geared Gori style. Love any feedback, experiences, etc...

I’m running a Universal M25XP with Hurth trans.

Chris
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author




There are other threads, so I will hunt around for them. Or you can.
I still have that nice $$ feathering prop, which served well for a decade, but it's presently in storage. I wanted more thrust for powering thru short seas and went to a three blade fixed prop a number of years ago. Paid a speed price when sailing, tho.
 
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Cbuydos

Member I
Thanks Loren. Did a forum search, but no too much on the Olson 34 and prop selection/use. Lots of info. from other Ericson boats. Prop selection varies greatly by boat, engine, & transmission. Really just curious about other Olson 34 owners and what they have been using with success or lessons learned.

Chris
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Other than the different stern hull section, the prop advice from EY owners will apply 99% of the time to our Olson's. We can motor a bit faster, which is nice, but our hulls and the Bruce King Ericson's are both very 'easily driven' hulls, so comparisons are more apt than you might assume at first. I have spent hours motoring along in company with an E-34-2, and our cruising speeds and observed wakes were very similar.

As for drive train, the Ericson's in our size range used the same Universal M25 or M25XP all thru the 80's and the transmission was a (approx) 2:1 Hurth model 50. There are some late-80's Ericson's and at least a couple of Olson's with a Yanmar, which to me just proves that EY would install whatever (reasonable) parts that the customer wanted. It might raise your eye brows a tad to contemplate the differences in winches on several different Olson's (and similar size Ericson's of that era, as well. :)

ps: if boating in salt water, check with your dock mates about whether they have had barnacles jamming up a geared prop. Something to consider.
 

debonAir

Member III
15 x 12 seems like a high pitch to me for a 34.. I was quoted 15 x 10 from Gori, and 16 x 9 from Flexofold for my E35. I suppose you could do the standard test of "does your engine get to max RPM at full speed / full throttle or does it lug a bit" and that would be your answer.

I don't think geared vs Martec matters wrt. pitch. The gears just insure the blades feather and extend in unison giving more reliable reversing, and avoiding the lazy-blade flopping down at low speeds that racers don't like.

Loren.. wanna lend me your $$ prop? I really like the flexofold but its a lot of boat bucks
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
I have this link bookmarked as a thorough discussion of prop issues:

 

67rway

Member II
Mine is a 15 10R Flexofold behind the factory M25XP. Capable of 3300 rpm, but I cruise it at 2800. Mild back to port issue.
 

racushman

O34 - Los Angeles
Mine is also a Flexofold. Not sure what model, it came with the boat.

I have limited experience as boat is new to me, but seems to work very well. Importantly, it backs well, which in my experience isn't always the case for folding props.

This link is to a very comprehensive test Yachting Monthly did on folding and feathering props. It looks like you have to join the email list to read. But what I recall is the FlexoFold scored remarkably well vs fixed and feathering... almost astonishingly well. Worth disclosing your email for a read: https://www.yachtingmonthly.com/gear/folding-and-feathering-propeller-test-29807

Before reading this I was considering a feathering prop. After reading I decided I had lucked out on the prop the prior owner selected.
 

Cbuydos

Member I
Thank you! This is exactly what I was looking for. Looks like I am off to pick-up Flexofold prop. The above link should be archived for all of the members. Extremely valuable information to help make an educated decision.

Chris
 

Slick470

Member III
We ended up with a Gori two blade geared folder which is very similar to the Flexofold. I spoke to all the prop vendors at the Annapolis boat show that year and while the price between the Gori and Flexofold were similar, I found the salesman for AB Marine who reps Gori in the US to be much more helpful. The Flexofold guy acted like I should buy his prop because it is the best and seemed put off that I would I even consider anything else. Honestly I had thought that the Flexofold was probably the best option before the show, but after my interaction with their rep I had no interest in one.

Good luck with whatever you end up with and I doubt you will go wrong with a Flexofold. We replaced a very undersized Martec folder and the difference in forward and reverse with the Gori is night and day.
 

Cbuydos

Member I
Just an end to the Season summary with the new Flexfold prop. Wow what a difference over the Martec. The prop really bites when you put it in grear. No more uncomfortable pause. Very little prop walk and almost instant control in reverse. It immediately gets flow over the rudder so the control in reverse is great. After the first season I am very impressed. Time will tell.

Chris
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Rob & Chris,
What is your experience so far with the FlexoFold? Did they get the pitch 'right'??
Gotta say, that three blade version looks mighty interesting....

Thanks much,
Loren
 

racushman

O34 - Los Angeles
Loren - my experience was very similar to Chris. I had the two blade version. Very solid thrust in forward. Remarkable performance in reverse, very modest prop walk. Seemed to almost defy the laws of physics for a folding prop (just like the article above said). I seem to remember mine was slightly over pitched... ~200 RPM short of red line during sea trial... but I never ran it that hard again, and was not worth bothering with.

Your mileage may vary, but if I had another sailboat it would be my first choice. Like I mentioned above, I originally assumed I would ultimately want a feathering prop for forward and reverse performance, but after a few hours of run time it became clear there was no need.

Hope that helps.

Rob
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
s. I had the two blade version. Very solid thrust in forward. Remarkable performance in reverse, very modest prop walk. Seemed to almost defy the laws of physics for a folding prop (just like the article above said). I seem to remember mine was slightly over pitched... ~200 RPM short of red line during sea trial... but I never ran it that hard again, and was not worth bothering with.
Did you give the vendor the requested info on their site form? Boat data, and engine and transmission ratios and etc? And they built the pitch from that info?
BTW, thanks (!) for sticking around the site and helping out!
 

racushman

O34 - Los Angeles
Sure thing Loren. The owner prior to me had installed the prop, so I didn't go through the process. I did find evidence somewhere in the boat papers that it took two props to get it right... the first one was over-propped.

Wish I could be more helpful.
 

Cbuydos

Member I
Loren, I have a brand new Universal in the boat and the pitch is spot on. There are some differences between the new 25 and the old ones, but they are close. Yes, just worked with the team overseas. Started with the online form and a few conversations over the phone and went from there. I’m very happy and highly recommend the FlexFold.

Chris
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Loren, I have a brand new Universal in the boat and the pitch is spot on. There are some differences between the new 25 and the old ones, but they are close. Yes, just worked with the team overseas. Started with the online form and a few conversations over the phone and went from there. I’m very happy and highly recommend the FlexFold.

Chris
Interesting! Which model and trans do you have?
As of 2018 I have a Betamarine25 in our boat.
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Yup. That engine model has been out for at least 20 years.
I love their promo for reasons why we should want one (and some of the listed features are indeed good ones) and then they say: "Engine prewired to plug-in connector" . OMG! :)

We looked at the new Universal closely back in 2018, and decided that we preferred the design and build of the marinization parts on the Betamarine, also using a Kubota short block.
 

bgary

Advanced Beginner
Blogs Author
Yup. That engine model has been out for at least 20 years.
I knew they'd been out for a long time, but I also thought Universal (as a company) was long gone.
I guess I imagined that, probably fueled by the rarity and cost of things like a genuine "Universal" water pump....
 
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