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Old 26-04-2014, 19:11   #16
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Re: from fixed to ?

Tolly-
My ex and I had two blade folding Martecs on her 45' cat, and we switched to two blade Flex-o-folds. Huge improvement, especially in reverse. Recommended to anybody. (Including big monos Dbraymer lol.)
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Old 26-04-2014, 19:14   #17
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Re: from fixed to ?

Plus 1 for our Flex-O-Fold 3 blade folding prop. 6 k boat speed at 2000 rpm, our most common motoring speed, but 6.5 at 2200, when needed. We have only had it 10 yrs., and the only maintenance has been lubricating it once a year when we are hauled out, and changing its zinc. And, of course, Prop Speed for anti-fouling has worked well.

We found the F-O-F vendor in Massachusetts a pleasure to work with: he was quite helpful, and well informed.

Ann
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Old 26-04-2014, 20:02   #18
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Re: from fixed to ?

Our Contest 48 is almost identical in dimensions to your CT47. We have a 90-hp Beta Marine engine coupled to a 24" Gori 3-blade prop. With over 20,000 miles on it (and way too much motoring), we're delighted with the prop. Here are some reasons:

1. The Gori prop has 2 speeds. The reverse attitude is a much higher pitch than the forward attitude. If you choose, you can put the prop in the reverse attitude and drive it in forward. Gori calls this feature 'overdrive'. With increased pitch in reverse, maneuvering in marinas is much easier.

2. There is no annual maintenance. There are easily replaceable rubber stops but these last a long time and can be replaced in minutes while the boat is in the water.

3. The special puller that's required to remove the prop comes with it.

4. Almost zero drag when folded.

5. The Gori prop costs less than most feathering props.

The only drawback I can think of to the Gori prop is that it uses special zincs that are expensive - I think I pay about US$60 per set but they last a long time on our boat, even though I replace them when they get down to about 50% of their original size.

Fair winds and calm seas.
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Old 26-04-2014, 20:29   #19
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Re: from fixed to ?

Quote:
Originally Posted by ontno1 View Post
Had a 44' boat, about 32,000 pounds with a Maxprop. Feathers, so little drag when sailing. Good forward power, and great backing ability. Adjustable so it can be set for a particular boat and engine. Mine needed a haulout for adjustment, but I think they make one that can be adjusted in the water.
The Easy Three Blade is the way to go. They are easy to install and are adjustable w/o hauling the boat. As long as you keep grease in them and the zincs fresh they'll last a long time.

The only down fall I've found is that one should not shift gears much above an idle. It mushrooms the stops on the blades which could lead to it not changing directions.

But on the other hand it makes one take better care of their tranny while shifting.

Here is a price list for last year. http://www.pyiinc.com/images/pdf/max...price_list.pdf
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Old 27-04-2014, 09:32   #20
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Re: from fixed to ?

My ex and I had two blade folding Martecs on her 45' cat, and we switched to two blade Flex-o-folds. Huge improvement, especially in reverse. Recommended to anybody. (Including big monos Dbraymer lol.)
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My major concern is how much difference it is in backing with folding (Flexofold) compared with my fixed ones. If you shift from one folding to another it might be an improvement if you're lucky, but going from fixed is another thing, I believe.
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Old 27-04-2014, 11:06   #21
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Re: from fixed to ?

Quote:
Originally Posted by Nicholson58 View Post
We have a Hundested 24" 3-blade infinitely variable with a hand crank adjustment in the cockpit. (0 to 90 degrees) 115 HP Westerbeke 6. 2:1 reduction gear. We run 8 - 10 knots at 1200 rpm engine speed. Our boat is 36 tons in the slings. This is the smallest variable Hundested makes but there are other manufacturers that are functionally the same.

It is especially nice to be able to flatten the prop at low speed for maneuvering in the marina or for maximizing the thrust to back out of mud or sand. Also, powering into heavy surf. We open up the blades as the boat speed picks up or water is flat, seas & wind following. These variable props are not cheap but they maximize performance under sail and stretch the fuel. The benefits are greater for larger boats and probably of little use on small & light vessels.
Variable pitch is a tremendous benefit; unfortunately rare in pleasure boat props. Hundested is the benchmark; I would really like the manual control. This is the one prop I, personally, would most like to have, but it is not available even for boats my size AFAIK (25 tons).

The most common variable pitch prop on pleasure boats is the Brunton Autoprop. Unlike the Hundested, it is self-pitching and so automatic, and there are several versions for any size boat. It is profoundly much better than non-pitching props for situations like motorsailing, where it is simply magical, or on the contrary when trying to power into rough seas. I have one of these and love it (had one on my previous boat, too, so I've actually been using them for nearly 20 years). There is a new version called the Eco Star or something like that, which is redesigned and apparently even better. Disadvantage of Autoprop is that it droops one blade when feathered so has more drag when sailing than any other feathering prop; but still a fraction of the drag of a fixed prop. Another disadvantage is that it is very expensive. An additional advantage of Autoprop, on the other hand, is that the blades turn all the way around in reverse, giving excellent power and bite in reverse and an excellent crash stop (after a slight pause while the blades turn around).

Maxprop is widely considered to be the best non-pitching feathering prop, and those who have them love them. They were original fit to Oysters for a long time (nowadays I think Oyster are using a lot of the Brunton Varifold props). Maxprop are now making their own self-pitching prop like the Autoprop -- certainly worth a look from this excellent maker. Maybe it will be cheaper than the overpriced Autoprop.

I would not consider folding props on a heavy ketch. Folders, as a general statement, have less drag but less bite than feathering props. They are good for catamarans and racing monos, or lighter boats.
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Old 27-04-2014, 11:40   #22
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Re: From Fixed Prop to?

Max Prop. Bulletproof, powerful. Go feathering.
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Old 27-04-2014, 12:15   #23
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Re: From Fixed Prop to?

The MaxiProp (= MaxProp?) is what we have and we're happy with it. I think any kind of MaxiProp can be adjusted while in the water, but the newer ones are very easy to adjust while the older ones have to be taken apart. I do that under water, even clean and grease them underwater.

Still, if I would have to buy a new prop, I would have a very long look at the Gori 3-blade.

Last but not least: prop-walk is an asset, not a negative
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Old 27-04-2014, 13:01   #24
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Re: From Fixed Prop to?

I got the information fram a manufacturer that fixed props on sail boats often are under dimensioned, to make the drag less. Therefore the feathering propeller cold be of larger size and/or with higher pitch. Anyone heard of that statement?

From the data of my boat with fixed 17X12 props, they recommended 19X13 feathering, to get the full power from the engines. Also since feathering, because of their flat blade surface, are not as efficient in forward as fixed of folding props.
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Old 27-04-2014, 13:06   #25
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Re: From Fixed Prop to?

Quote:
Originally Posted by s/v Jedi View Post

Last but not least: prop-walk is an asset, not a negative
I agree in all aspects. We had a 50ft Colin Archer type sailing yacht for 17 years, 5 tons Skandia semi diesel engine with manually adjustable pitch on a 4ft diameter 3 blade propeller. Prop-walk was the largest help when docking. Used well it is definitely an asset.
On my catamaran though, I don't even feel it.
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Old 27-04-2014, 19:21   #26
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Re: From Fixed Prop to?

[QUOTE=s/v Jedi;1528076]The MaxiProp (= MaxProp?) is what we have and we're happy with it. I think any kind of MaxiProp can be adjusted while in the water.............. [/QUOTE

They no longer use the "i". And the easy props can be adjusted with the twist of a dial.

Max Prop > Company
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Old 27-04-2014, 19:32   #27
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Re: From Fixed Prop to?

I researched all fall and winter.

it came down to 4 choices - Kiwi, Gori, Autostream, and Flex-o-Fold.

my final decision was the Flex-o-Fold.

it was a very easy install...

have a look at this article:

http://www.flexofold.com/upload_dir/...onthly_low.pdf

it is on their web site but it has some good info about all the props you may be looking at.
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Old 27-04-2014, 20:07   #28
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Re: from fixed to ?

Quote:
Originally Posted by Dockhead View Post
Variable pitch is a tremendous benefit; unfortunately rare in pleasure boat props. Hundested is the benchmark; I would really like the manual control. This is the one prop I, personally, would most like to have, but it is not available even for boats my size AFAIK (25 tons).

The most common variable pitch prop on pleasure boats is the Brunton Autoprop. Unlike the Hundested, it is self-pitching and so automatic, and there are several versions for any size boat. It is profoundly much better than non-pitching props for situations like motorsailing, where it is simply magical, or on the contrary when trying to power into rough seas. I have one of these and love it (had one on my previous boat, too, so I've actually been using them for nearly 20 years). There is a new version called the Eco Star or something like that, which is redesigned and apparently even better. Disadvantage of Autoprop is that it droops one blade when feathered so has more drag when sailing than any other feathering prop; but still a fraction of the drag of a fixed prop. Another disadvantage is that it is very expensive. An additional advantage of Autoprop, on the other hand, is that the blades turn all the way around in reverse, giving excellent power and bite in reverse and an excellent crash stop (after a slight pause while the blades turn around).

Maxprop is widely considered to be the best non-pitching feathering prop, and those who have them love them. They were original fit to Oysters for a long time (nowadays I think Oyster are using a lot of the Brunton Varifold props). Maxprop are now making their own self-pitching prop like the Autoprop -- certainly worth a look from this excellent maker. Maybe it will be cheaper than the overpriced Autoprop.

I would not consider folding props on a heavy ketch. Folders, as a general statement, have less drag but less bite than feathering props. They are good for catamarans and racing monos, or lighter boats.


I bought an AutoProp for my boat and it was terribly problematic, despite my continuous efforts to strictly follow the manufacturers maintenance schedule. I finally left it on a 'Free to a Good Home' table at one of the yards where we were hauled out. Even the quickest search will return dozens of other boat owners who have had problems with these props.

Please clarify for me your statement about folding props on heavy ketches. My experience with my folding Gori is that it has plenty of 'bite'. We have a 24x18 prop with a transmission reduction of 2.5:1. At 1,400 RPM, we cruise at 6 knots in calm conditions and burn about .9 gallons of diesel per hour. The engine reaches it maximum RPM - 2,600 - at WOT and the boat reaches it's hull speed, 8.3 knots. I don't see where I'm missing any 'bite'.

Fair winds and calm seas.
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Old 27-04-2014, 20:12   #29
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Re: From Fixed Prop to?

+1 vote on the Hundestedt, we love ours.
I have dived and worked on many "Adjustable" propellers, adjusting pitch, clearing lines, replacing parts and anodes etc. The Maxprop is a good choice, never had problems with them except for "other" peoples' mistakes in assembly or pitch setting, and easy to work on. Nice reverse thrust for a slight loss in ahead being an un-raked blade.
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Old 03-05-2014, 08:10   #30
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Quote:
Originally Posted by dbraymer View Post
Vessel is CT 47 ketch, about 40,000 pounds fully loaded, 4-154 Perkins 65HP with beautifull 3 blade 17 inch fixed propeller installed, thought to be 12-14 inch pitch. We can't find a mark... Vessel motors easily 6 knots at 2000 indicated RPMs, 6.5 at 2200.

I have never ventured into any prop except fixed, although I did fix a stop on the shaft on my schooner with a two blde prop hidden in the full keel slip stream. Ensenada race. No, we did not win.

The CT can go like snot, and we have very loud prop screaming above 8 knots degenerating into shuddering. So I have to fix this. Velvet drive so far holding up OK.

If I go folding, I think Gori 3 blade makes sense. If I go feathering, anyone have an idea? The more I Read, the more confused I get, probably the residual of a college education in physics.

We are cruisers who just hate to motor, but occassionally being able to motor to protection is a priority. So I guess minimal drag first prority, then forward motoring ability next, then reliability/ease of maintenance third.

Pardon my headbanger, not so good at this posting stuff. I am normally an answer guy!
Do find a way to stop spinning the prop! The original manual stated that it could be spun indefinitely. Later manual notes starting the engine every few hours up to a certain rpm above that it had to be stopped (from memory)

In my case, sailing downwind in a cal cruising 35 at 7 knots the prop was screaming and then stopped.

I started the engine and all appeared OK. Turned out I spun the reverse bearing in the gear pack. Motored home from the bahammas via the icw and at that time there was metal in the oil.

The rebuild was 2500 in 1995. A max prop was less money than another rebuild.

Good luck and change oil often.
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