Why buy a FLEX-O-FOLD PROP?

FLEX-O-FOLD Cruising The best model for the sailor looking for powerful thrust in forward and reverse. The new blade design outperforms any fixed, feathering or other folding prop when motoring and has the lowest drag under sail. It will add 10% to your daily cruising range and improve your motoring efficiency. The ideal weight distribution of the heavy blades provide exceptional stopping power, even at low rpms. Features larger, heavier blades than the Racing Model.
FLEX-O-FOLD 3-Blade For large engines and where there is a need for maximum thrust and least possible vibration. Blade stops are cushioned by strong poly-urethane springs. A zinc anode covers the gears and provides protection.
FLEX-O-FOLD Racing For the very lowest drag with excellent performance under power. A proven winner!! "The Flex-O-Fold slipped through the water like a greased squid". Cruising World June 1996.
Flex-O-Fold is not the only folding or feathering prop on the market but it is obviously the best!! It's technical design, superior construction and beautifully machined finish combine to give you superior performance and long life. Blades are shaped for maximum thrust forward and reverse and the husky helical gears control them in every position.
PERFORMANCE COMPARISON *
Manufacturer	Fwd Pull	Max Speed	Max Speed	Drag	Under	Sail(Lbs.)
	Max Lbs.		Under Load	2Kts.	4Kts.	6Kts.
Autoprop 3B1 Feather	182@3800rpm	6.90@3075	4.65@3375	5	10	18
Campbell Sailor 2blFixed	172@3025rpm	6.25@3400	3.80@3000	4	16	29
Campbell Sailor 3blFixed	193@2925rpm	6.50@3100	4.30@3000	7	21	43
Cruising Design 2blFeather	178@3275rpm	6.40@3800	4.20@3775	2	7	13
Cruising Design 2blFold	197@2990rpm	6.80@3200	4.67@3075	1	3	5
Flex-O-Fold 2blFold	235@2975rpm	7.15@3400	4.65@3175	1	1	2
Martec 2blFolding	165@3500rpm	6.70@3675	4.40@3400	1	2	3
Martec 3blFeather	188@3200rpm	6.40@3575	410@3200	2	6	9
Maxprop 2blFeather	170@2900rpm	6.80@3700	4.15@3300	1	2	5
Maxprop 3blFeather	155@3550rpm	6.90@3550	4.50@3100	2	4	7
Maxprop 3blFeather	155@2700rpm	7.00@3750	5.00@3550	4	13	3

*Cruising World June 1996

TEST RESULTS

Many propeller tests have been conducted over the past 20 years both by manufacturers and independent organizations. While the manufacturer-sponsored tests may have validity, the published results often emphasize those attributes in which that manufacturer excels. The independent tests, on the other hand, may not have this bias, but may have test parameters that do not reflect reality. The two tests having both independence and well-designed test methodology are the one conducted in the U.S. by "Cruising World Magazine" in 1995, printed in their June 1996 issue, and the test conducted in Germany by the Technische Universitat Berlin in 1997 for "Die Yacht Magazine" and printed in their May, 1997 issue. See notes below.

CRUISING WORLD TESTS, 1995

Forward Pull (lbs)	Reverse Pull (lbs)

Maximum Speed (Knots)	Drag (Lbs)

TEST METHODOLOGY:

These tests of powering performance and drag were conducted on a Freedom 35 using a Yanmar 3GM30 engine. Participants were asked to supply their best propeller for that application. The results for the major brands are shown below. Other propellers were also tested but are not included in the results below. In our opinion, those props omitted do not change the conclusions.

NOTE: these tests were completed using "old style" Flex-O-Fold Propellers. The current Standard Propellers have larger blade areas than the "old style" Flex-O-Folds, resulting in significantly better performance, particularly in reverse.

TECHNISCHE UNIVERSITAT TEST, 1997

Efficiency (%)	Drag (Newtons)

*Note to efficiency graph: A achieved this efficiency at approximately 10 knots. Efficiency increased to 65% at significantly higher speeds. Efficiency at lower speeds was consistently below F-O-F and P.

**Note to drag graph: Drag of A increased to 670 N (150 lbs) if allowed to rotate. Drag of P increased to 420 N (94.5 lbs) if locked.

TEST METHODOLOGY:

This test was conducted at the Technische Universitat Berlin in their test tank. The primary methodology was to determine the efficiency of each 3-blade propeller submitted at various "rates of advance" or speed. Efficiency is defined as the percentage of horsepower converted into thrust. Also tested was propeller drag, with the props mounted at a zero shaft angle, as would be the case with a sail drive.

NOTE: the test of the Flex-O-Fold Propeller was conducted after the original test had been completed, as the Flex-O-Fold was not ready for sale at the time of the original test. However, given that the test was under tightly controlled conditions, in an indoor tank, we are confident the results would have been the same had all props been tested at the same time.