Okay- I have a 94 Hunter 335 on the Chesapeake with the Yanmar 3GM30 engine turning a fixed two bladed prop. I do both club racing and weekend/week long cruising on the Bay and am considering getting a folding or feathering prop to improve sailing performance. What do I give up from a performance under power perspective? Also what are the pros and cons of feathering versus folding? Is a three bladed feathering/folding better then a two bladed - I assume its more expensive- Any help you can give me to aid my quest would be appreciated.
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Prop Upgrade
Nigel, I have a 1993 legend 37.5, I also do a fair amount of club racing and cruising, about 3/4 yr's ago I replaced the standard 2-blade fixed prop with a Jensen 2-blade flex-o-fold and without a doubt I'm more pleased with this upgrade more that any other piece of equipment that I have added to the boat.I gain any where from a minimum of 1/2 to 1 full knot increase under sail in most wind ranges. Probably the most benefical!, under power across all rpm ranges 1/2 knot increase vs the 2-blade fixed and more thrust and better control/steerage in reverse. My decision to buy the Jensen vs other brands was prompted by an article in Cruising World where they did real in the water tests using a Tartan 31 or 33 footer with all the popular 2 amd 3 blade fixed, folding and feathering props and the best I remember the Flex-o-fold was rated #1 under sail (producing the LEAST amount of drag) #2 for reverse performace and #3 or 4 for forward performance. I may still have the Crusing World edition if your interested. Hope this helps! Capt. Ron
Nigel, I have a 1993 legend 37.5, I also do a fair amount of club racing and cruising, about 3/4 yr's ago I replaced the standard 2-blade fixed prop with a Jensen 2-blade flex-o-fold and without a doubt I'm more pleased with this upgrade more that any other piece of equipment that I have added to the boat.I gain any where from a minimum of 1/2 to 1 full knot increase under sail in most wind ranges. Probably the most benefical!, under power across all rpm ranges 1/2 knot increase vs the 2-blade fixed and more thrust and better control/steerage in reverse. My decision to buy the Jensen vs other brands was prompted by an article in Cruising World where they did real in the water tests using a Tartan 31 or 33 footer with all the popular 2 amd 3 blade fixed, folding and feathering props and the best I remember the Flex-o-fold was rated #1 under sail (producing the LEAST amount of drag) #2 for reverse performace and #3 or 4 for forward performance. I may still have the Crusing World edition if your interested. Hope this helps! Capt. Ron
Props yet again
Jan.5, 2000 Dear Nigel, Ron has given you some good advice on this and you will want to check the archives where there is a growing library of correspondence on "props" to help you with the decision. Practical Sailor also did real world testing with feathering and folding props and the results they got would appear to confirm what Ron said. In summary PS found that folding props produce less drag than feathering props but the feathering props were more efficent under power than the folding props in both forward and reverse. We've got a three bladed Maxprop that we are very pleased with. If performance under sail is more important to you then punching into a chop under power then I like Ron's choice of the Jensen as well. On the other hand, because we are long distance voyaging having power when needed in remote parts of the world tipped the scales for us to favour the feathering option. It is a fact that both feathering and folding props will give far superior performance under sail to a fixed prop. Whether you opt for 2 or 3 blades comes back to the question of which side of the equation you wade in on in terms of power verses sail performance. If you absolutely positively have to win that race and are a die hard sailor then the answer is 2 blades, folding. On the other hand if having power for the weekend and week long cruises is important you will want 3 blades and I would suggest a feathering prop to squeeze the last ounce of power out of this choice. Fair winds, Brian Pickton of BeneteauOwners.net Aboard the Legend, Rodney Bay St. Lucia
Jan.5, 2000 Dear Nigel, Ron has given you some good advice on this and you will want to check the archives where there is a growing library of correspondence on "props" to help you with the decision. Practical Sailor also did real world testing with feathering and folding props and the results they got would appear to confirm what Ron said. In summary PS found that folding props produce less drag than feathering props but the feathering props were more efficent under power than the folding props in both forward and reverse. We've got a three bladed Maxprop that we are very pleased with. If performance under sail is more important to you then punching into a chop under power then I like Ron's choice of the Jensen as well. On the other hand, because we are long distance voyaging having power when needed in remote parts of the world tipped the scales for us to favour the feathering option. It is a fact that both feathering and folding props will give far superior performance under sail to a fixed prop. Whether you opt for 2 or 3 blades comes back to the question of which side of the equation you wade in on in terms of power verses sail performance. If you absolutely positively have to win that race and are a die hard sailor then the answer is 2 blades, folding. On the other hand if having power for the weekend and week long cruises is important you will want 3 blades and I would suggest a feathering prop to squeeze the last ounce of power out of this choice. Fair winds, Brian Pickton of BeneteauOwners.net Aboard the Legend, Rodney Bay St. Lucia
Agree with Ron, . . .
check the web-site and give them a call(http://usboat.com/jensen/). Not too expensive(everything is relative
, a simple install, and both forward and reverse are much improved on my H37C.
check the web-site and give them a call(http://usboat.com/jensen/). Not too expensive(everything is relative
, a simple install, and both forward and reverse are much improved on my H37C.Flex-o-fold
I too can attest to the performance of the 2 blade flex-o-fold. Unfortunately, Ole Jensen is no longer associated with Flex-O-Fold and the new url is www.flexofold.com. They offer 2-blade cruising and racing props. Primary difference that the cruising version has more space between blades when closed and more blade area and weight near the tips. The wider spacing and increase weight near the tips provides additional inertial force to open the prop, especially when there is forward motion. The penalty is slightly more drag on the cruising versus racing version. I had the racing version on an Express 35 with a 24 horse Yanmar. Forward performance was excellect (6.5-7 kts at 2400 RPM. Reverse was acceptable, but could definitely not make a panic stop by putting boat in reverse while going at full speed. A friend has the 2 blade cruising version and his reverse perfromance was very good. I'm ordering a 3 blade Flex-O-Fold for our new Hunter 460. I also believe that the Flex-o Fold has better forward performance than the Maxi-Prop since feathering props have very flat blades. The blade profile of a Flex-O-Fold (in forward) is better than featering props. Maxi-Props feathering feature probably provides better reverse performance than the Flex-O-Fold. Also, Flex-O-Fold is about half the price of an equivalent Maxi-Prop.
I too can attest to the performance of the 2 blade flex-o-fold. Unfortunately, Ole Jensen is no longer associated with Flex-O-Fold and the new url is www.flexofold.com. They offer 2-blade cruising and racing props. Primary difference that the cruising version has more space between blades when closed and more blade area and weight near the tips. The wider spacing and increase weight near the tips provides additional inertial force to open the prop, especially when there is forward motion. The penalty is slightly more drag on the cruising versus racing version. I had the racing version on an Express 35 with a 24 horse Yanmar. Forward performance was excellect (6.5-7 kts at 2400 RPM. Reverse was acceptable, but could definitely not make a panic stop by putting boat in reverse while going at full speed. A friend has the 2 blade cruising version and his reverse perfromance was very good. I'm ordering a 3 blade Flex-O-Fold for our new Hunter 460. I also believe that the Flex-o Fold has better forward performance than the Maxi-Prop since feathering props have very flat blades. The blade profile of a Flex-O-Fold (in forward) is better than featering props. Maxi-Props feathering feature probably provides better reverse performance than the Flex-O-Fold. Also, Flex-O-Fold is about half the price of an equivalent Maxi-Prop.
which one?
Hello Nigal, Thank you for your note. Whether you switch to a feathering or a folding propeller the impact to your forward motoring efficiency should not change all that much. You may see some differences in maintaining forward speed when confronted with heavy winds or sea with the folder but all in all not much change. The major differences between the two styles of props start at your reverse. Reverse for a folder can range from no change to a substantial loss of control. A feathering propellers reverse efficiencies often duplicate its forward efficiencies but this increase can, however, result in no change or could even enhance the walking problem you may currently experience. Sailing speeds with both units will be apx. the same. Costs for either a folding or feathering two blade configurations can range from $300 to $1,400 depending on the brand. Most folding propellers come in a two-blade configuration, Gori I believe now has a three blade folder, where most feathering propellers company’s have both two and three blade units. Most three blade units run from apx. $1,900 to $2,100. The only time a three blade is not a better choice over a two blade is when the two pounds of drag difference is a priority. A three blade will help keep the running gear quite and smooth. In most cases a three blade is as much as 30% more efficient. This helps to maintain the speed of the vessel when it is confronted with heavy winds or seas. My own personal choice of a propeller is a three blade feathering. Hope this helps you. Sincerely Kevin.
Hello Nigal, Thank you for your note. Whether you switch to a feathering or a folding propeller the impact to your forward motoring efficiency should not change all that much. You may see some differences in maintaining forward speed when confronted with heavy winds or sea with the folder but all in all not much change. The major differences between the two styles of props start at your reverse. Reverse for a folder can range from no change to a substantial loss of control. A feathering propellers reverse efficiencies often duplicate its forward efficiencies but this increase can, however, result in no change or could even enhance the walking problem you may currently experience. Sailing speeds with both units will be apx. the same. Costs for either a folding or feathering two blade configurations can range from $300 to $1,400 depending on the brand. Most folding propellers come in a two-blade configuration, Gori I believe now has a three blade folder, where most feathering propellers company’s have both two and three blade units. Most three blade units run from apx. $1,900 to $2,100. The only time a three blade is not a better choice over a two blade is when the two pounds of drag difference is a priority. A three blade will help keep the running gear quite and smooth. In most cases a three blade is as much as 30% more efficient. This helps to maintain the speed of the vessel when it is confronted with heavy winds or seas. My own personal choice of a propeller is a three blade feathering. Hope this helps you. Sincerely Kevin.
3-blade feathering for me
I have a 93' 33.5 and I purchased a Martec 15" 3 blade for my 3gm30 and what a difference. The engine is alot smoother now.. I Paid $1400 installed. Better speed and the pitch can be changed in the water.. I had the pitch increased after it was installed to fit the boat. Try that with others.. My vote is to go 3 blade.. Not 2.. Also Backing/STOPPING is great!
I have a 93' 33.5 and I purchased a Martec 15" 3 blade for my 3gm30 and what a difference. The engine is alot smoother now.. I Paid $1400 installed. Better speed and the pitch can be changed in the water.. I had the pitch increased after it was installed to fit the boat. Try that with others.. My vote is to go 3 blade.. Not 2.. Also Backing/STOPPING is great!
3-blade feathering 2
On our 97' 40.5 with a Volvo MD22L 50HP, we just added the Martec Autostream 18" 3-blade feathering prop with forward pitch set at 13" and reverse pitch set to 12". Our previous prop was a Martec 18X16 fixed 2-blade we used for 3 years and 600 houts of run time. What a difference. Before 2500 RPM = 7.3, now 7.6 and better fuel economy. The engine runs smoother now and backing down is great. Before we had to leave the transmission in reverse to prevent freewheeling but could not shift back to neutral without starting the engine (not good). Now no problem, it doesn't freewheel in neutral. I found it on Martec's web site and paid the list price of $1824. I had received a quote from AutoProp for $3010. This month we motored sailed up the East Coast from Ft Lauderdale to Baltimore and put 200+ hours on the engine in lots of different conditions including major start/stops in the narrow New River of downtown Ft Lauderdale on a Friday with LOTS of boat traffic. Great test right out of the gate. Stuck between 2 bridges with BIG powerboats & sailboats and a strong current with no place to go or tie up. You get the picture. Control with the new prop was great. I highly recommend it. As far as sailing performance goes the operative word is 'feathering'.
On our 97' 40.5 with a Volvo MD22L 50HP, we just added the Martec Autostream 18" 3-blade feathering prop with forward pitch set at 13" and reverse pitch set to 12". Our previous prop was a Martec 18X16 fixed 2-blade we used for 3 years and 600 houts of run time. What a difference. Before 2500 RPM = 7.3, now 7.6 and better fuel economy. The engine runs smoother now and backing down is great. Before we had to leave the transmission in reverse to prevent freewheeling but could not shift back to neutral without starting the engine (not good). Now no problem, it doesn't freewheel in neutral. I found it on Martec's web site and paid the list price of $1824. I had received a quote from AutoProp for $3010. This month we motored sailed up the East Coast from Ft Lauderdale to Baltimore and put 200+ hours on the engine in lots of different conditions including major start/stops in the narrow New River of downtown Ft Lauderdale on a Friday with LOTS of boat traffic. Great test right out of the gate. Stuck between 2 bridges with BIG powerboats & sailboats and a strong current with no place to go or tie up. You get the picture. Control with the new prop was great. I highly recommend it. As far as sailing performance goes the operative word is 'feathering'.
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