Pros and Cons of folding props

[steveolearys]

In advance, please excuse me if I break any protocol and feel free to enlighten me. Are folding props vs fixed worth the expense, and maintenance? Thank you.

[CarlF]

It’s the #1 improvement you can make to sail faster. Whether that’s worth the cost depends on how much you care.

[George_SD]

Benefits:
- faster under sail
- less chance of collecting weeds/kelp
- quieter (true for 2 blade vs 2 blade)
- reduction in vibration (true for 2 blade vs 2 blade)

Cons
- more expensive
- requires more maintenance
- often needs more frequent zinc replacement
- can be slower
- often worse thrust in reverse (requires more RPM, but totally manageable)

Worth it or not is subjective. Was worth it for me only when I found a good used one at 1/10 the cost.

[gs41escapade]

I replaced the fixed prop on my last boat with a 'feathering', not folding prop. Did the replacement myself which cost me a few skinned knuckles and a full pack of metal blades for the sawzall to cut the 1" stainless shaft for the install.

Net result, about 1/2 -3/4 knot additional speed in the middle wind range. Reverse was actually improved over the fixed prop as the feathering blades reverse and bite well. I'm very happy I did it.

[Ballsnall]

Pro: The folding ones fit in your handbag easier.
Con: Lots more parts to fall off mid ocean

[double u]

Originally Posted by CarlF

It’s the #1 improvement you can make to sail faster. Whether that’s worth the cost depends on how much you care.

...& very probably the most cost effective!

[JPA Cate]

We have had folding props of different blade numbers over the years and boats. Definitely in the pro side of the discussion. But one time, we tried a feathering prop. It cost us 25% more in fuel consumption, but worked better in reverse.

For the last few years we have had a 3 blade Flex-o-Fold. However, their business has been taken over, and I cannot speak for the new product. We have been pleased with ours, and definitely think they are better than whatever came with the boat. However, keep the old one for a spare.

Ann

[Searles]

Fitted a number of feathering composite Kiwi props verry good astern and ahead ,also good price ,worth the check out .⚓️⛵️

[Off Trail]

Agree with the positives. Easiest and most cost-effective upgrade for boat speed. Grease once in a while, and keep an eye on the anodes (we haven't noticed any increased anode loss). We have a Flex-o-fold 3-blade.

[derfy]

If you are racing, feathering or folding props is the only way to go.

But there is lots of gear essential to racing that make little sense to cruising.

Folding props are a serious maintenance and reliability item - below the waterline, on a critical function. There is definitely a tradeoff.

I had one (DM me for the brand) - it came with the boat. Previous owner swore by it. It was the first thing I had to repair - cost $1700 for a factory "reconditioning". Sold it a year later for $1700.

I did not see the predicted 1/2 to 3/4 kt speed loss when I switched to a fixed three-blade workhorse prop. I saw practically no difference in speed under sail, and better performance under power.

Why? Because I allow my prop and shaft to turn freely in neutral - an operating mode that my manufacturer (Yanmar) specifies as the correct and proper mode under sail for my transmission.

BUT - many diesel transmissions require that the shaft be locked with an external shaft clamp when sailing, or to be sailed in gear - some in forward, some in reverse (a whole 'nother thread). If you have one of these, then yes you will see a 1/2-3/4 knot speed hit when sailing with a fixed blade prop with the shaft locked. A folding prop eliminates the need for a shaft lock.

Vertical sail drives I have used (live Volvo) specify the prop to freely turn under sail, and I have raced head to head against boats of the exact same type with feathering props and beat them over the line. Very little advantage when using sail drives tuning freely. I don't love sail drives for cruising. Would not have one. But I notice many cats use them.

It is essential to know, for your transmission, if the shaft can turn under sail without damage, or must be locked. If it can turn under sail, I recommend a fixed 2- or 3-blade prop.

The negative to a fixed prop on a turning shaft is the additional wear and tear on the packing gland flax when under sail. This has not been a problem. I pack my own - an essential skill - and notice no particular wear at all. It is always in good shape when I have repacked it and I take care to adjust it properly. I do get water drip into the bilge when I sail as the shaft turns.

Finally, I ask, how often is the 1/2 knot under sail making a huge difference in your transit time? Yes, crossing to the Caribbean in light to medium air, it matters - a day or two from the East Coast. But offshore the wind usually blows hard and I am reefed down and furled just to keep the boat on its feet. We are a hull speed, and the prop is not a factor when there is that much wind power.

Or, I am motoring-sailing into steep chop or foul current and need all the power and efficiency I can get - and a prop that works every time, on demand.

Or, I am getting thru a hole in the wind and again need an efficient prop to power thru using as little fuel as possible.

I never seem get those halcyon day-after-day passages in the trades I keep reading about. Yes, a 1/2 knot would save days in that case.

Cheers and Fair Winds

[DoubleD]

Originally Posted by George_SD

Benefits:
- faster under sail
- less chance of collecting weeds/kelp
- quieter (true for 2 blade vs 2 blade)
- reduction in vibration (true for 2 blade vs 2 blade)

Cons
- more expensive
- requires more maintenance
- often needs more frequent zinc replacement
- can be slower
- often worse thrust in reverse (requires more RPM, but totally manageable)

Worth it or not is subjective. Was worth it for me only when I found a good used one at 1/10 the cost.

For "- less chance of collecting weeds/kelp", I assume that is for a folding prop, when folded. I would think a feathering prop would not have this feature and all props while turning would have the same chance of picking up unwanted items. I currently have a fixed three blade that came with the boat, but have on my extended cruising improvement list to change to a folding or feathering prop.



DD

[Cheechako]

I prefer feathering to folding. Great thrust and reliability with a well known model.

[Cheechako]

Originally Posted by gs41escapade

I replaced the fixed prop on my last boat with a 'feathering', not folding prop. Did the replacement myself which cost me a few skinned knuckles and a full pack of metal blades for the sawzall to cut the 1" stainless shaft for the install.

Net result, about 1/2 -3/4 knot additional speed in the middle wind range. Reverse was actually improved over the fixed prop as the feathering blades reverse and bite well. I'm very happy I did it.

yep, I've had 6 Max Props over the years (2 of them were used/came on a cat, 2 more were used on monos, 2 were new I bought). I never had an issue with any of them. Good thrust and great reverse compared with fixed props. These were just standard old school Max Prop 3 blades.

[Orion Jim]

I replaced my Michigan three bladed fixed with a Max-Prop Easy three bladed feathering prop last year. The thrust increase in both forward and reverse is readily apparent, especially reverse. There is a slight speed increase due to reduced drag which is noticeable but whether it’s a half knot or more would be conjecture on my part. Thus far I have not caught any weed on it but my trip through the sargassum north of Bermuda in the spring will provide a real test.

[Adelie]

Whether a folding or feathering prop is going to benefit you while cruising will depend on how committed you are to using the boat as a sailing machine.

If you are willing to continue sailing even though boat speed has dropped to 2kt or less then it will be worth it.

If you are the kind of person to start the motor whenever speed drops to 4kt, don't bother.

I would suggest coastal cruising the boat for a season to see where your frustration level kicks in for slow speed sailing.

The advantages of folding over feathering are
A. Used folding props can be found very cheaply.
B. Folders have mediocre performance in reverse generally, some do OK.
C. Folders have marginally less drag than feathering.
D. Folders are mechanically simpler which suggests higher reliability. I have no data or history to support this opinion.
E. Folders won't snag lines in the water when not under power.

Advantages of a feathering prop.
A. Cool tech
B. Generally the pitch can be adjusted if it wasn't set quite right to begin with.
C. Better reverse propulsion.

Once again, if you aren't committed to the sailing, it probably isn't worth it.