Composite Propellors?

Question

Has anybody had any experience with composite propellers vs Aluminum or stainless. This is for Volvo duprops with 200hp plus being driven into them.

On paper they seem to be desirable being non corrosive and replaceable blades.

Answer 1

I would never put them on my boat. I have 26' Larson with Volvo Duo Prop. After watching the way aluminum props rot away (i keep it in the water, all summer) I switched to Stainless Steel. I had to change the pitch a little, but I would never go back to aluminum.

If something is floating in the water and your composite prop hits it. That it for you. You need to jump in and change props on the spot. That means you need to carry a set of spares. Perhaps even two sets.

And with 200 plus HP, they will flex, and you will lose power.

don't do it.

Answer 2

believe me if its rated for the size and force it can withstand it. the difference between and what you might want to look at is where you are running the boat at, because yeah S/S props are really strong but sometimes they are too strong if you ever hit anything with the prop it may tear the hole lower unit out because it has no flex or relief unlike aluminum or composite ; where if you hit something with one of them aluminum will bend or flex and can be fixed or composite you may tear a chunk out but is "A lot" more inexpensive and is better in salt water. so if you stay in big open water S/S is the way to go, you'll never have to worry about it again. But if you go though a lot of shallower water lake stumps or ocean coral reef aluminum or composit is the way to go. If you know there is a danger of damaging the prop composite, because you can buy almost three or four props for the price of one S/S and have no worries of lower unit dammage....PS if its speed or power your looking for that in the pitch and number of blades you have. hope I helped and have fun on the water.

Answer 3

the comp prop is really used as backup not fulltime use

Answer 4

If they are as good as the material of helicopters, is great!  I worked on a company that makes Composites, I did the quality control for them.  So I am very familiarized with their capabilities.  Carbon fiber is really strong, depending on what resin system and fibers are used.  Just for a example on the material made for the Boeing 777 flaps, the tensile strength is about 10,000-11,000 MSI (Mega Pounds x Squared Inch) and is 1.25 wide and about .10 of a inch thick.  On a sample is .25 of an inch wide and .10 thick on the same sample and take 500 lbs to compress it to failure.  So is pretty strong.

Now beware of some, on the ones that we regected they were bought for sporting goods, since those numbers will never be reach, lets say on a tennis racket.  So they are a lot of "Aerospace Grade" factory reject materials on sporting goods :-)

I would say on a Propeller is not, is dangerous to have a rotating mass at high speed disintegrate and really sharp shrapnel flying around.  I will buy it, but will be expensive to fix if it gets damage or too expensive to buy.

Is up to you, if you are racing and weight savings is paramount !

Good luck !

Answer 5

All the different props have pros and cons.

Costs, dependability, life and other related issues.

A normal aluminum prop will corroded unless you keep your zincs replaced when they get eaten out past 50%.  When you hit something, the blades tend to bend and can be straightened/rebuilt if you know how.  In sandy/silty water, the prop will wear faster than normal.

Stainless Steel is strong and won't corrode, but when you hit somethink like a log or rock, the shock is suppose to be absorbed by the rubber hub, but sometime that doesn't do enough and you can rip out interal gears in the drive system.  SS is very good in abrasive water where sand and silt is common that wears other props.

Composite props don't corode and shatter when you hit a hard object and need replacement more often, but the drive system will last much longer which is very expensive to replace/repair.  In sandy/silty water, it will eat a prop fairly fast.

Figure our what your need for a prop is and pick the one that best suits your enviorment.

No matter what prop you use, a spare should always be carried because there is a lot of rocks and debre floating in the water to hit... life of boating.

Answer 6

VERY SIMPLE:

Composite props are cheap and work great for an emergency (spare prop).

Aluminum props are great if you are boating in water you aren't familiar with.

Stainless steel works best because if wont flex,delivers strong power and ONLY RUN IF WATER YOU KNOW!

What I mean by this is if you hit something w/SS you will greatly increase  your chances of lower unit damage!!

Now on the other hand check with your insurance comp for UNDER WATER DESTRUCTION insurance this is for just that you cant see it and hit it your insurance will cover it! Mine costs $13.00 extra on the policy -- WELL worth it!!