Propeller

[Blueshedar]

HI,

J want to change the propeller of may Hunter 50 with a 3 free blade folding.
It's a good idea?.
j've forget the pitch and the diameter of my blade ? Can you help me?:neutral:

 

[Bill Roosa]

Depends

What do you have right now?

Why do you want to change the prop?

 

[Ross]

What do you have right now?

Why do you want to change the prop?

He can't remember!



He has a few thousand dollars burning a hole in his pocket.

 

[Blueshedar]

What do you have right now?

Why do you want to change the prop?

To improve sailign performance

 

[Blueshedar]

I have no money to throw. I'm trying to figure out if I can improve the performance of the boat in light winds is slow folding dimension to the initiatives that would allow me to gain 20%

 

[Blueshedar]

Now i have a normal 3 blade

 

[Scott T-Bird]

It's a good idea which will come with a pretty high price tag. The information that you will need to have is:

Your engine make and model.
The gear ratios of your transmission in forward and reverse.
The length, beam and weight of your sailboat (your weight with a normal full load).
The shaft diameter (or do you have sail drive?).
Helpful information would also include the diameter and pitch of your existing prop and the clearance that you have between the tip of the existing prop and the underside of the hull (you don't want to increase the diameter if the blade can hit the hull).

Take that info to the prop makers that you favor and let them work out the details for you. You can then compare and price it out and make your decision.

 

[RichH]

Yes it is definitely good idea, but it will have increased cost. Having a fixed three bladed prop is like dragging a bucket of the same diameter though the water when the engine isnt 'on'. Not only will the boat be slower, but it wont be able to 'point' as well as a boat with a folding/feathering prop.

If you can adequately FIT a 3 blade 'folder' (you have to watch out that 'swing of the blades' doesnt come in contact with the rudder, etc.) you will most definitely have less drag; hence, increased sailing performance/speed, etc. A more common alternative, albiet more expensive, is a three blade 'feathering prop' - Max. prop, Auto-prop etc. more thrust, a a wee little bit more drag than a 'folding prop', if you cant dimensionally FIT a 'folder' ... most 'folding props' are 2 blades. The newer feathering props can easily have their pitch changed --- without having to haul the boat out of the water to do so. Folding props generally are more 'robust' than feathering props due to their more simplistic design. Why not a TWO bladed folding prop - martec, (volvo?), etc.?

Folder or Feathering --- definitely go for it; and, stop dragging that 'bucket' around.
For a H49, I would guestimate a ~1 to 1.5+ knot speed increase near the 'top end', faster acceleration out of a tack, better lightwind performance, less vulnerable to 'crab/lobster floats/warps'. etc. etc. etc. etc.

 

[Prime Time]

Made the switch last spring

On my Bristol 43.3, I installed a Max prop 3 blade feathering type to replace a fixed 3 blade prop. I absolutely saw an improvement in light air performance. In 5-8 knots apparent, I would say I improved my speed by 0.25 to 0.5 knots. PHRF figured 5 sec per mile.

I chose the max prop due to their long history of reliability. However, there are many good choices out there.

Is that worth the price? That is a personal choice. Since I cruise and race, it was to me. Over a 10 hour day cruising, it saves about half an hour to an hour, doesn't seem like much.

 

[Prime Time]

Other thoughts

I saw no increase in top end while sailing. Hull speed is just that. I can reach hull speed more easily.

The pitch that was recommended was a bit to little. I lost 0.5 knots under power at 80% WOT. I am going to change it this winter. I bought the version that you need to be on the hard to change the pitch. The version that is adjustable in the water requires a diver or you to have diving equipment.

The boat handles better in reverse than it did with the fixed prop.

Feathering props tend to do better in reverse than folding props like the martec.

Some props find the best pitch setting automatically (auto prop and others I think). I you really motor or motor sail a lot, that is something to consider.

 

[Rick D]

The light air performance increase on my boat was huge. It really transformed the boat. Since you are in Italy, I would tend to rely on local preferences for your prop since you will want to have access to repair and service parts and knowledge. I would also e-mail Hunter to get your current prop size and pitch. Good luck!

 

[Blueshedar]

It's a good idea which will come with a pretty high price tag. The information that you will need to have is:

Your engine make and model.
The gear ratios of your transmission in forward and reverse.
The length, beam and weight of your sailboat (your weight with a normal full load).
The shaft diameter (or do you have sail drive?).
Helpful information would also include the diameter and pitch of your existing prop and the clearance that you have between the tip of the existing prop and the underside of the hull (you don't want to increase the diameter if the blade can hit the hull).

Take that info to the prop makers that you favor and let them work out the details for you. You can then compare and price it out and make your decision.

thank you

 

[Blueshedar]

Thank you

 

[Blueshedar]

The light air performance increase on my boat was huge. It really transformed the boat. Since you are in Italy, I would tend to rely on local preferences for your prop since you will want to have access to repair and service parts and knowledge. I would also e-mail Hunter to get your current prop size and pitch. Good luck!

Thank you

 

[Blueshedar]

I saw no increase in top end while sailing. Hull speed is just that. I can reach hull speed more easily.

The pitch that was recommended was a bit to little. I lost 0.5 knots under power at 80% WOT. I am going to change it this winter. I bought the version that you need to be on the hard to change the pitch. The version that is adjustable in the water requires a diver or you to have diving equipment.

The boat handles better in reverse than it did with the fixed prop.

Feathering props tend to do better in reverse than folding props like the martec.

Some props find the best pitch setting automatically (auto prop and others I think). I you really motor or motor sail a lot, that is something to consider.

Thank You

 

[Blueshedar]

yes It Is Definitely Good Idea, But It Will Have Increased Cost. Having A Fixed Three Bladed Prop Is Like Dragging A Bucket Of The Same Diameter Though The Water When The Engine Isnt 'on'. Not Only Will The Boat Be Slower, But It Wont Be Able To 'point' As Well As A Boat With A Folding/feathering Prop.

If You Can Adequately Fit A 3 Blade 'folder' (you Have To Watch Out That 'swing Of The Blades' Doesnt Come In Contact With The Rudder, Etc.) You Will Most Definitely Have Less Drag; Hence, Increased Sailing Performance/speed, Etc. A More Common Alternative, Albiet More Expensive, Is A Three Blade 'feathering Prop' - Max. Prop, Auto-prop Etc. More Thrust, A A Wee Little Bit More Drag Than A 'folding Prop', If You Cant Dimensionally Fit A 'folder' ... Most 'folding Props' Are 2 Blades. The Newer Feathering Props Can Easily Have Their Pitch Changed --- Without Having To Haul The Boat Out Of The Water To Do So. Folding Props Generally Are More 'robust' Than Feathering Props Due To Their More Simplistic Design. Why Not A Two Bladed Folding Prop - Martec, (volvo?), Etc.?

Folder Or Feathering --- Definitely Go For It; And, Stop Dragging That 'bucket' Around.
For A H49, I Would Guestimate A ~1 To 1.5+ Knot Speed Increase Near The 'top End', Faster Acceleration Out Of A Tack, Better Lightwind Performance, Less Vulnerable To 'crab/lobster Floats/warps'. Etc. Etc. Etc. Etc.

Thank You

 

[RichH]

Max Props are manufactured in ....... Italia