Do you have any information about the new three blade flex-o-fold prop. They claim it has the highest forward speed and pull, the greatest efficiency and the reverse charateristics of feathering propellers. I know that folding props in general have some major drawbacks. Are the company claims justified. Thanks (I would be using it on a Catalina 400)
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Fritz Merizon
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I too intend to add a folding prop to my boat. Had intended to go with Auto-prop until the dealer recommended the Gori, 3 blade folding model. I would welcome some impartial advice!
I too intend to add a folding prop to my boat. Had intended to go with Auto-prop until the dealer recommended the Gori, 3 blade folding model. I would welcome some impartial advice!
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Ed Schenck
Not much help.
Except to say that I have a Flex-O-Fold two blade. It does what the company owner said it would do and was priced right. But since I was mostly interested in sailing fast I have never given it a thorough test I suppose. With a 20HP Yanmar and a 37-foot boat over 18000# it has powered me through some tough weather. It backs significantly better without prop walk. I make about 5.5 knots at 2200 RPM. Never tried max throttle. Beautifully finished, great install method. Just make sure you have the clearance between end of shaft and rudder.
Except to say that I have a Flex-O-Fold two blade. It does what the company owner said it would do and was priced right. But since I was mostly interested in sailing fast I have never given it a thorough test I suppose. With a 20HP Yanmar and a 37-foot boat over 18000# it has powered me through some tough weather. It backs significantly better without prop walk. I make about 5.5 knots at 2200 RPM. Never tried max throttle. Beautifully finished, great install method. Just make sure you have the clearance between end of shaft and rudder.
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Tim
email Chuck Angle
I also bought a 2-blade Flex-O-Fold for me Beneteau First 32. I really like it. The geared blades negate the need to "position" the shaft to ensure both blades go to the streamline position. Email Chuck Angle at cangle@wellsyachts.com, and ask him to send you the technical and comparison sheets Flex-O-Fold has. They are informative on very specific test results on Flex-O and several other brands. good luck! Tim
I also bought a 2-blade Flex-O-Fold for me Beneteau First 32. I really like it. The geared blades negate the need to "position" the shaft to ensure both blades go to the streamline position. Email Chuck Angle at cangle@wellsyachts.com, and ask him to send you the technical and comparison sheets Flex-O-Fold has. They are informative on very specific test results on Flex-O and several other brands. good luck! Tim
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RonD
This is the info Chuck gave me:
The following is quoted from a very recent e-mail from Chuck (who I know personally and respect as an honest guy): -------------------- "Comparing one prop with the next is not easy, especially when most comparisons are subjective and vary depending on the breadth of experience. However, there are a couple of independent tests that have been done that help. One was done by Cruising World Magazine in 1995 and was published in June of 1996. In that test were many of the popular brands, including Flex-O-Fold, but not Gori. The Flex-O-Fold tested was an older model with significant improvements having been made since. "The second was done by Technische Universitat Berlin for Die Yacht Magazine and published in May of 1997. That did not include Flex-O-Fold as it was a test of 3-blade props and we did not yet have a 3-blade prop available. Later that year, when the prop was ready, we had the Professor who did the original test repeat it using our entry. Because that test was in a tank under carefully controlled conditions, we feel the comparisons are fair and have a letter from the Professor complimenting us on our fine product. "If you want, I can send you the results. Briefly, Flex-O-Fold did very well. In the Cruising World test, they measured forward pull, reverse pull, speed, speed with a drogue and drag. On the maximum pull test, maximum speed: Flex-O-Fold 2-blade 235 lbs 7.15 kts Martec Folding 165 lbs 6.70 kts MaxProp 2-blade Feathering 170 lbs 6.80 kts Autoprop 3-blade Feathering 182 lbs 6.90 kts Michigan 2-blade Fixed 191 lbs 7.00 kts "In the reverse pull, which is not a good test (what you want to measure is acceleration), we faired less well. However, the new blade design has increased reverse thrust by about 40%. The results in the same order: FOF 97 Martec 79 Max 145 Auto 122 Michigan 112 "In the drag test, the drag at 6 knots was measured with a 15 degree down shaft angle: FOF 2 Martec 3 Max 5 Auto 18 Michigan 29 "In the Die Yacht test, we again did well. They studied 3-blade props only and measured the efficiency (defined as the percentage of horsepower converted into thrust) over a range of speed of the various brands. The results, maximum, and the drag at 8 knots with a 0 degree shaft angle (note Gori substituted for Martec): FOF 64% 2.7 lbs Gori 53% 2.7 lbs Max 46% 3.0 lbs Auto 56%* 16.9 lbs Prowell Fixed 62% 94.5 lbs "Note: the Autoprop efficiency shown is at 8 knots. The efficiency improves as the speed increases, exceeding the Flex-O-Fold curve at about 12 kts "In reverse, the test was again inconclusive. The reverse efficiency curves for all competitors crossed the Flex-O-Fold curve at a speed of about 3 knots or higher. The Flex-O-Fold curve remained higher at lower speeds. "As far as barnacles and the like are concerned, I am asked that question often at boat shows. I suggest the questioner place his or her finger in a place that, if fouled, could cause a problem. Few, with good cause, take the challenge, as the prop would mangle the finger or a barnacle when it opens. At the mooring, the down shaft angle alone is enough to close the blades, keeping the barnacles away from the gears." -------------- --Ron
The following is quoted from a very recent e-mail from Chuck (who I know personally and respect as an honest guy): -------------------- "Comparing one prop with the next is not easy, especially when most comparisons are subjective and vary depending on the breadth of experience. However, there are a couple of independent tests that have been done that help. One was done by Cruising World Magazine in 1995 and was published in June of 1996. In that test were many of the popular brands, including Flex-O-Fold, but not Gori. The Flex-O-Fold tested was an older model with significant improvements having been made since. "The second was done by Technische Universitat Berlin for Die Yacht Magazine and published in May of 1997. That did not include Flex-O-Fold as it was a test of 3-blade props and we did not yet have a 3-blade prop available. Later that year, when the prop was ready, we had the Professor who did the original test repeat it using our entry. Because that test was in a tank under carefully controlled conditions, we feel the comparisons are fair and have a letter from the Professor complimenting us on our fine product. "If you want, I can send you the results. Briefly, Flex-O-Fold did very well. In the Cruising World test, they measured forward pull, reverse pull, speed, speed with a drogue and drag. On the maximum pull test, maximum speed: Flex-O-Fold 2-blade 235 lbs 7.15 kts Martec Folding 165 lbs 6.70 kts MaxProp 2-blade Feathering 170 lbs 6.80 kts Autoprop 3-blade Feathering 182 lbs 6.90 kts Michigan 2-blade Fixed 191 lbs 7.00 kts "In the reverse pull, which is not a good test (what you want to measure is acceleration), we faired less well. However, the new blade design has increased reverse thrust by about 40%. The results in the same order: FOF 97 Martec 79 Max 145 Auto 122 Michigan 112 "In the drag test, the drag at 6 knots was measured with a 15 degree down shaft angle: FOF 2 Martec 3 Max 5 Auto 18 Michigan 29 "In the Die Yacht test, we again did well. They studied 3-blade props only and measured the efficiency (defined as the percentage of horsepower converted into thrust) over a range of speed of the various brands. The results, maximum, and the drag at 8 knots with a 0 degree shaft angle (note Gori substituted for Martec): FOF 64% 2.7 lbs Gori 53% 2.7 lbs Max 46% 3.0 lbs Auto 56%* 16.9 lbs Prowell Fixed 62% 94.5 lbs "Note: the Autoprop efficiency shown is at 8 knots. The efficiency improves as the speed increases, exceeding the Flex-O-Fold curve at about 12 kts "In reverse, the test was again inconclusive. The reverse efficiency curves for all competitors crossed the Flex-O-Fold curve at a speed of about 3 knots or higher. The Flex-O-Fold curve remained higher at lower speeds. "As far as barnacles and the like are concerned, I am asked that question often at boat shows. I suggest the questioner place his or her finger in a place that, if fouled, could cause a problem. Few, with good cause, take the challenge, as the prop would mangle the finger or a barnacle when it opens. At the mooring, the down shaft angle alone is enough to close the blades, keeping the barnacles away from the gears." -------------- --Ron
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