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Random Quote: I caught you a delicious bass. - Napoleon Dynamite
I finally broke out hte digital calipers and measured some blade thickness today. I recently purchased a Mercury Enertia which claims to have a thinner blade but my first impression was that it was no thinner then an average propeller. I measured the prop at the leading edge about 3/8" back. This measurment seemed pretty consistent as far back on the balde as i could measure with the calipers. At about an inch or so I could no longer measure do to the curve of the blade and the depth of the jaws on the tool I was using.
The Enertia averaged 0.12" through the middle of the leading edge being a little thicker toward the hub and thinner toward the tip. The trailing edge averaged about .017".
I have a stock untouched Mercury LaserII so I measured that and it measured the same 0.12 through the leading edge confirming my initial impression. The trailing edge was actually thinner averaging 00.15".
Since I still have my labbed Rev4 I checked that as well and was not suprised to find it measured 0.08" through the leading edge.
So...Mercury's Enertia is not thinner then a stock LaserII. The next time I see Ken from Propgods I will take my calipers and make some more measurments but I suspect my findings will be pretty consistent. I like the way the Enertia works on my boat but it is not thiner. That makes me wonder how it would react to some thinning
That's a very scientific measurement there Glen. However, a minute is a looooong time to hold something that heavy straight out. I don't think I can go a minute holding out a 12 pounder. You better measure again, and lets hear the "hull truth."
That's a very scientific measurement there Glen. However, a minute is a looooong time to hold something that heavy straight out. I don't think I can go a minute holding out a 12 pounder. You better measure again, and lets hear the "hull truth."
jim
the point is the Enertia is half the weight of all the other props of same size and pitch...
Yes, its lighter but to quote Mercurys own words :
"Improving hole shot and top speed with the same propeller is virtually
unheard of in the marine industry – typically, if a prop change improved
acceleration, it would diminish top speed, and vice versa. Because the strength
of X7 allows for thinner blades, Enertia can provide gains in both acceleration
and top speed."
I would suspect that the rduced weight has much to do with its great acceleration. Weight does not affect ultimate top speed, just the time it takes to get there. I agree its a bunch lighter. I have noticed that this prop is showing signs of rust much faster then other Merc props I have had (and thats most of them). My prop is rinsed and wiped off after every trip so I was suprised to see some small rust spots after a couple trips. I suspect that the new alloy contains some more iron then the rest of the props. The hub design also contributes to the reduced weight and the large blade with small diameter keeps that weight close to the hub where it is easier to accelerate.
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The blades could be thinner in the places you didn't measure, or the overall amount of metal could be less if the blade area, blade root thickness, hub thickness, etc. was reduced.
Glen - just for the heck of it, could you please at some point submerge your three 19P props in a bucket of water and see how much water they displace? I.e. this would give the net total volume of each propeller. If we could then somewhere dig up the respective weights of these props, we could then calculate the net volume weight for each alloy and see if the X7 is that much lighter in itself, or if it merely allows a slimmer geometry.
I stand corrected..the enertia is a bunch lighter.....argue that....
A bunch relates to Banana's. Banana's should not be on or around a boat. I thought we were talking props?
When you do the water displacment trick be sure to measure the specific gravity of the water that is used. Some water weighs one amount and other water may way a bunch more. Are we talking fresh water, salt water or heavy water?
Yes, its lighter but to quote Mercurys own words :
Because the strength of X7 allows for thinner blades, Enertia can provide gains in both acceleration and top speed."
Probably written by the marketing department and technically correct. What is left unsaid is that the delta thickness between one type of prop blade and the other is being measured to the ten thousandth of an inch (millimeter in the case of a Yam, Honda, Suk).
Bingo Jethro! If you read between the lines, it says the new alloy allows for for thinner blades. It doesnt say they actually made them thinner.
I also agree that the blades may be thinner at places where I could not measure and if that is one small place then they are accurate but its the leading edge that makes the real difference.
One of the neat things about the Enertia is the large blades even with a smallish diameter. Because the blade is very long ( a lot of rake) it actually has more blade surface area then a smae pitch Mirage Plus. Because this area is closer to the hub, it is easier to accelerate and I would bet that is where the Enertia name was derived.
I was going to weigh the two I have today but then realized my LazerII has the old solid hub.
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Propeller blade thickness Enertia vs. others 
