Flexofold Prop

[Bearlakesailor]

OK, I couldn't get anyone here to tell me that they have a Maxprop or Flex-O-Fold so I did my research & decided on the Flex-O-Fold. I bought it direct from them & Dan was very good to work with. He told me some things I didn't know so I thought I would pass them on to everyone here. First off, I went with a size 15X10 based on Dan's advice. Because the prop mounts further aft, you can go back up to the 15" Prop. He also told me that you should never use a two-blade on this boat because we have a "shaft-log" where basically our prop shaft is not exposed. In this situation, one blade will frequently be right behind the shaft-log not getting a good bite in the water. One other thing he told me, the Anode he sent me was "magnesium" rather than "zinc", because apparently zinc doesn't work well in fresh water.

Installation was a breeze although it took some extra hands to get all the pins inserted! I have only motored with it but it is a VAST improvement over the 14x10 fixed prop that I replaced. MUCH more thrust in both forward & reverse. I will post some more information once I have sailed with the prop but so far...I am very pleased with the results. I have attached a couple of pic's for you to see what it looks like.

Enjoy the SUMMER!

Justin
License to Chill
#185

[wolfe10]

I went with a size 15X10 based on Dan's advice. Because the prop mounts further aft, you can go back up to the 15" Prop.

Justin
License to Chill
#185

Justin,

Not clear from this if you went with the 15X10 or 14X10???

Please let us know if it is sized properly:

1. With engine warmed up and in NEUTRAL, advance throttle to the WOT (wide open throttle) for just a few seconds-- enough to record maximum RPM on your tach. This step eliminates ASSUMING that the tach is accurate. The engine governor is generally a LOT more accurate than the tach. So, tach reading with engine "on the governor" is a more meaningful number.

2. With engine in FORWARD, throttle to WOT, RPM should be 100-150 RPM below the reading in 1. above.

If the tach quickly goes to the same RPM as in 1. above, the prop is too small (diameter and/or pitch).

If you are 200 or more RPM below that in 1. above, the prop is too large (diameter and/or pitch).

Would really appreciate your exact RPM's as well as boat speed at (you tell us at what) cruising RPM.

Thanks.

Brett

[Bearlakesailor]

Sorry Brett, I went with a 15x10 prop. I will try to do what you suggested & post later here...should be interesting?

Justin

[Bearlakesailor]

Brett, this may be a stupid question, but my throttle lever doesn't allow me to go WOT without being in gear? I just have a single lever & there doesn't appear to be any way to disengage the transmission? Am I missing something here or is there a "trick"?

I can tell you that I don't believe my knotmeter is reading correctly...when I open it up in flat water to WOT, the tach reads 2700rpm & my knotmeter says about 5.2 knots? I will have to calibrate the knotmeter next time I am up. The boat get's to that speed MUCH quicker than with the old prop but I also see some black smoke at WOT?

More to follow...

[wolfe10]

MY RESPONSES IN SOLID LETTER CAPS.

WE HAVE EXACTLY THE SAME PROP. I AM SURPRISED THAT THEY ARE RECOMMENDING THAT SIZE-- IT IS LIKELY THAT A 15X9 or 14X10 WOULD BE A BETTER CHOICE. SAID ANOTHER WAY, WE ARE OVER-PROPPED. THAT DOES MAKE FOR FAST MOTORING, BUT YOU HAVE TO WATCH THAT YOU ARE NOT OVERFUELING AND/OR OVERHEATING. WE JUST DID A LITTLE UNDER 3,000 MILES THIS WINTER FROM TEXAS TO THE BAHAMAS AND BACK--MUCH OF THAT MOTORING OR MOTORSAILING.

Brett, this may be a stupid question, but my throttle lever doesn't allow me to go WOT without being in gear? I just have a single lever & there doesn't appear to be any way to disengage the transmission? Am I missing something here or is there a "trick"? ON OURS, PUSH IN THE BUTTON IN THE CENTER OF THE PIVOT ON THE THROTTLE/SHIFT LEVER TO DISENGAGE TRANSMISSION AND ALLOW FULL USE OF THROTTLE. IN FACT I USE THIS TO BRING THE ENGINE TO A LITTLE HIGHER IDLE SPEED UNTIL WARMED UP ON COLD START-UP.

I can tell you that I don't believe my knotmeter is reading correctly...when I open it up in flat water to WOT, the tach reads 2700rpm & my knotmeter says about 5.2 knots? I will have to calibrate the knotmeter next time I am up. The boat get's to that speed MUCH quicker than with the old prop but I also see some black smoke at WOT? 5.2 KNOTS IS VERY SLOW FOR WOT WITH THAT PROP. CLEAN BOTTOM, CALM WATER I YOU SHOULD BE OVER 6.3 AND PROBABLY OVER 6.5. DO CALIBRATE THE KNOTMETER WITH A GPS OR POST GPS NUMBERS IN FLAT WATER OR TWO WAY AVERAGE IF IN AN AREA WITH CURRENT. BLACK SMOKE IS A SYMPTOM OF BEING OVER-PROPPED AS THE ENGINE IS FUELING AT A RATE TO GIVE MAXIMUM RPM'S, BUT THE RPM'S ARE LOWER THAN SPECS, SO LESS AIR TO FUEL RATIO.

More to follow...

[sailorbob]

Brett is correct - pushing in the button on the throttle handle while moving the handle forward leaves the transmission in neutral.

I never did replace my 15 x 9 - does anyone know if Catalina still has the 14 x 10 Michigan Wheel prop available, and at cost, as was the deal when Gerry posted his analysis?

Bob
#301

[yodagwb]

Brett I am fighting what I consider a somewhat slow boat. I did replace the stock prop with the 14-10 but I typically run at about 5-5.5knts. When I did the WOT test there was no difference in the max RPMs between neutral and forward. I am seriously considering a Flexofold given that they seem to rate the highest in forward thrust tests. You say you are over proped at 15-10. How much of a problem is being over proped? Would you purchase the same prop again? Have you ever have the boat weight checked when you were hauled and if so what was the weight? I ask this because I was around 22000lbs. We are getting ready for a Florida run next fall from the Chesapeake and 5 knts seems like a very long, slow trip.

[wolfe10]

Yodagwb,

Can't say whether I would go back with the 15-10 or not. Depends on boat performance/RPM with next smaller prop. Said another way, would love to try the very next smaller prop.

With an oversized prop:

Good: Good boat speed for engine RPM
Bad: Can overheat and if run at WOT, can do engine damage due to overheating and sooting.

Never weighed this boat, but when we go somewhere, it is LONG DISTANCE and we are loaded. Typical trip is Texas to Bahamas. Bottom and prop are always clean.

[saileagleswings]

With a clean bottom & 14X10 prop, I get six kts at 2400 rpm in absolutely flat water. The boat slows down alot just motoring as chop increases. Last week, I only managed 5.2 kts. You might ask what Catalina 36 owners get; the 36 has the same engine and I believe the same transmission but the 36 isn't as beamy so it doesn't slow down as much.

We have a boat that sails great and provides alot more comfort at anchor than a skinny sea boat. Too bad we seem to be going dead to the wind so often.

If you find a prop that improves performance without overloading the engine I would like to know. Thanks

[leigh weiss]

For those who are looking for a solution to the prop issue, I think I have selected a winner.
I am using a KIWI Feather Prop with 15.5" blades.
Did the WOT test and needed to adjust (fine tune ) the pitch. Dive on the prop and change pitch with an allen wrench.
Very easy install. Just put it on the taper and secure the nut.
I did install a thin zinc collar behind the prop.
When installed, it was quiet and moved the boat at 6.5 Kn. @ 2850 RPM. no black smoke.
Great for backing up as well!
The feathering feature was great for sailing, did not have to shift into reverse to stop the shaft from turning. I also purchased 3 spare blades. They can be replaced in the water.
You might want to check out the KIWI web page.
I ordered mine from a dealer about 4 years ago and I think it was under $1300 with shipping (DHL from NZ.)

Leigh Weiss Brisa #155

[yodagwb]

Leigh - question do you know what pitch you settled on with your 15" Kiwi?

Brett - what kind of speeds are you seeing with yours being over proped?

The original prop on the Catalina 350 was a 15-9 sail prop. They later went to a 14-10 Michigan Wheel prop to combat the cavitation issue. Their logic being some elusive to me. I read somewhere that they down sized the prop because they felt the tip of the 15" was moving a bit to fast and that was causing the cavitation. I also read that they down sized it to reduce the drag when locked and sailing and increased the pitch to compensate for the loss in speed . The long and short of it is that the is a huge difference in the blade surface area between the Sail 15-9 and the Michigan Wheel 14-10, the ladder having much more area to displace the load (forward side pressure reduction) over, even though it is a smaller prop. If the 15-10 is a substantial over prop concern then my first thought would be to go with the Flexofold 15-9. I say that because I feel I lost some smooth water top end speed when they changed the props from 15-9S to 14-10M. If there are any others with a 15-9, 15-10, 14-10 or 14-11 feather or fold prop I would definitely like to hear what you seeing in motoring speed and loading(chop).

Bill Yeomans

[Pgtjs]

Hi there,

Before you change anything, you might check two other strands of postings on this "Hull Prop and Rudder" Forum. Specifically "Weight of Boat" and "Autoprop". I think it can be concluded that a loaded C350 weighs in at about 22-23,000 lbs. I also get about 6.5 knots (measured on a two way test at slack tide using the Raytheon Chart PLotter to get SOG). The Hull speed is about 7.3 and I can get 7.1 for short periods at max revs before it starts to overheat. I run at 2850 rpms and 180F and the said 6.5 knots all day with no problems. There is no visible black exhaust smoke or residue.

I have a Yanmar 3YM30 engine - 30hp with a Kiwi prop - overall this package is lighter than the Michigan prop and Westerbeke combination. The Kiwi prop is simply excellent and if you hit a semi sunken log - as I did once - one or more blades may break off and can be easily replaced by a diver in the water with an Allen screw driver. The pitch can also be changed in situ - we did this when it was new 6 years ago and lightened up 1 degree on the setting as supplied by the factory. Recently I had to have it lifted and serviced after a "Kevlar/Nylon" piece failed and it lost it's tension on the spring used to flip over into reverse. But no big deal and I'm told that the new piece is much tougher as a result of their experience elsewhere. The dealer came and changed it over himself at no charge which was kind of neat. The Kiwi unit does need to be lubricated whenever the boat is lifted out which is easy to do after you see him do it once - it needs marine grease and an injection pin style grease gun nipple. I was not aware of this requirement but the factory grease lasted the six years anyway. The dealer said it should last at least a couple of years between liftouts.

I had a Max Prop on a previous boat - and think the Kiwi prop is at least equal and much cheaper. Plus the Max Prop has to be sent to the distributor which takes two weeks if it needs a repair - in this case, the zinc failed and flew off, apparently bounced off the hull and dinged the "brass alloy" prop causing a dent on one tip the size of a nickle. Including the "rebalancing", it cost $400+ and no boat use for that time. My best guess is that the Kiwi prop adds about 3 or 4/10ths to the sailing speed in light winds compared to the fixed blade (factory supplied) prop. It is feathering not folding - and unless you are racing that does not matter IMHO. I dont know if there is a different PHRF adjustment in the handicap calculation for the Kiwi prop.

I have also previously posted a comment about calibrating Ratheon speed instruments - mine was showing about 5 knots before I adjusted it using the SOG reading from the Chartplotter as mentioned above. The instrument seems to default to a factory base whenever the battery power source is disconnected ie. at battery changeover. You can reset it to always show the SOG or adjust it to be based on the "spinner" reading plus a "C.F." factor which is what I want. Right now the CF is set at 1.60. That way it shows about 6.5 knots at slack - and if I am motoring against or with the tide, the tidal effect is apparent.

Cheers, Geoff. C350 - #392 Taeko 1V, Blaine, WA.

[leigh weiss]

question: do you know what pitch you settled on with your 15" Kiwi?
I used the design guide provided by KIWI It came shipped with the pitch set.
Out of the box is was close, but needed a slight "tweak" or fine tuning. 1/4 turn with an Allen wrench.
The same root/hub will fit the 14" or 15" blades. I have an extra blade set for quick replacement.
The question of the actual weight of the boat (loaded), might have been the variable for the need for the fine tuning. I have the winged keel.

Leigh Weiss Brisa #155

[Pgtjs]

Hi Leigh,

I do not know what the factory setting was. Like yourself it was "set" when it was shipped. After it was installed I had problems getting it to high revs without overheating and the dealer let it off 1/4 turn at the lift out the next year and that solved it. At this latest liftout, after the forward spring tension retainer hub split, we thought about letting it off another quarter but I opted to stay as is. The only advantage I could see in reducing another quarter was for the engine to run at higher revs and that uses more fuel. It seems to run all day at 6.5knots and 180F/2850 rpms and no black smoke. It can max out at 3500 rpms and get close to the hull speed. Hence I decided ..."if it ain't broke, don't fix it!".

So perhaps you would need to ask the dealer/KIWI. If you need help, there is a good dealer in Vancouver BC who belongs to the same yacht club as me and I could let you have his number. He recently sold his business and retired but I'm sure he would be helpful over the phone. He came down here to the US (Blaine, WA.) to change the split hub at no charge - said it was a nice day to ride his motor bike. He told me that there had been problems with the hub piece and they had changed the material some years ago. So if yours is coloured white it is an old version. The new one looks to be the same material as the blades - ie black.

I have not kept a spare set of blades as I can get replacements quickly if I need them from the dealer who stocks them. Besides hopefully I wont hit another log. Another sailing friend does carry a spare set as well. The issue would be to get them when we are away up north in the islands and there is no regular transportation delivery service and few liftout locations so one would need to sail home anyway. That is what happened last time.

By the way, I was remiss in not lubricating the prop until this latest liftout. Apparently this should be done whenever it is lifted. Easy when you know how and is shown in the owner's " instruction manual".

Hope this helps,

Geoff. C350 #392, Taeko 1V, Blaine WA.

[leigh weiss]

Geoff,
When I purchased the KIWI prop it had 14" blades with a spare set of 15" blades. I have used both and adjusted the pitch (in the water) on both sets with speed and performance tests. From the results I have left the 15" blades on. No cavitation but I can't tell you the "pitch" setting as it has changed from several adjustments. This fine tuning approach seems IMHO to be my best bet as the weight, engine and other variables might cause different results for each boat. If you want to try a set of 14" blades you can borrow these and evaluate them. I will be out of the water from Nov. 1 until April 15.
Catalina might want to consider the KIWI prop as standard/option because of the flexibility of the design including replaceable blades and easy pitch adjustment.

Leigh Weiss Brisa #155

[yodagwb]

Brett-

Just back from Annapolis boat show. Trying to figure out the gear reduction was a lot of fun. Had to take a picture of the gear box tag and take it to the Universal people to get a translation on to English. Nothing in my manual that states what the reduction is, only what optional ones would be, nice. Turns out I have a Universal (Blue), not Westerbeak (Red), M35B with a gear reduction of 1.88 in forward and 1.99 in reverse. Upon giving that info to the Flexofold guy he came back with a recommendation of a 15:9, 3 blade prop. The reference book he (Flexofold) had showed a 1.9 reduction in which case he was recommending a 15:10. I hope everyone is adequately confused by now. I am starting to think that each Catalina 350 is different and maybe what I really have is a custom boat.

Bill #108

[leigh weiss]

Bill,Brett and others,
For those and other reasons I went with the KIWI.
The ability to "fine tune" the pitch to the boat was my intention. ...It worked!


Leigh Weiss Brisa #155

[yodagwb]

Justin and Brett

You both have the 3 blade Flexofold 15/10. Is it safe to assume you guys also have the Universal M35B motor with the 1.88 transmission reduction? I ask because I am hull # 103 and I am not to sure as to when they went to the Yanmar motors which seem to have a very different gear reduction.

[Windseeker]

I'm very interested in a new prop. Mostly for backing this big fat pig into my slip. I just finished reading an informative 27 page, 398 post thread on propellers. I definitely want a feathering prop that can rotate their blades around 180 degrees so the leading edge is presented in reverse. From all the discussions I read, it will help tremendously. I like the KIWI for the price, but I'm concerned about the durability of the blades with debris I run into on the Chesapeake. I saw the Autostream at the Annapolis Boat Show. Very Beefy. Very Impressive. I also like the Variprofile (on paper) for its slim design and low drag. The Autoprop is a really neat prop, but it doesn't match my current boating style.

What other props have you used or considered?

[leigh weiss]

I have the M35B engine in Hull number 155. I am using the Kiwi prop for about three years in the upper Chesapeake. Have hit lots of things and have not suffered any damage. I did order spare blades with the prop and carry them with me. They can be changed in the water with little effort. The web page for Kiwi has a copy of the service manual with detailed instructions for blade replacement. Another boat near me also has the Kiwi prop with no problems. As I said in my other post, I have fine tuned the pitch to limit the RPM to 2950 @WOT. (With a calibration optical tachometer) I cruse at 2300-2400 RPM. The backing thrust is very impressive, there is no discernible cavitation noise, even from a dead stop to high speed. The boat is on the hard in south Jersey until late April if you want to look at the install.

Leigh Weiss Brisa #155