Try Prop’n Fun!
12X12, 12X11, And 13X12 Only we know how to read this!
I bet you are thinking, hahahaha Woody Boater miss spelled Try? Didn’t he mean Tri Props? This past weekend I learned about “Try Props”, which is a thing that used to be done at dealers so you could dial in your preferred way of boating with a different prop. They would give you three, “Tri” – and you would “Try” them and return the two.
Props, Props and more props – It’s over Propulation…. Anyone? No? Sorry.
This past weekend we did just a tradition with three props from Katzs Marina, and Dave VanNess with Stink’s new engine.
Gas Pass Special is running perfect now
Here is the situation. Stinkys original engine was a 75HP H. Her prop calls for a 12X13 prop. Okay got that?
The Stink!
Looks a tad odd.
She never reached over 2200 RPM. Which saved the engine as long as it did. But this was because at some point her prop was made to a 13X12. Someone inverted it. We do not know why? Has 1938 stamped on it. And to add to all this, I am guessing about 300Lbs of fiberglass on her.
13X12
Now a more powerful H, 95Hp with some tweeks, to possibly speed her up. The 20 hp got her up to 2500RPM.
Calls for a 12X13
NEW PROP. We got a 12X12 and 12X11
12X12 perfection
The 12X12 hit the nail on the head. 3100 RPM. And speed perfect. The 12X11 just more rpm but the speed was not increased, and honestly at about 2700 RPM, she is about top speed. This is all felt by the way, we will be GPS testing later.
View this post on Instagram
The Tri Prop deal worked out great. Thanks to Katzs Marina and VanNess Engineering. Now we need to tweak Main Jet Needles. UGH.. Everyday is a learning day.
View this post on Instagram
A Huge thanks to John from VA who found a very cool Stinky flag!
Sorry but that flag has to go. It’s 2018 and Pepé Le Pew is now recognized as a stalker and rapist!
#metoo
12X12 is a common size. We have shallow water here. Current stock of 12X12 nibral cupped props.
Have you tried any four blades?
12 x 12 on my 17 Deluxe with 95K does 32 mph at 3100. That must be the magic prop for the little boats!
Interesting. My 17′ runabout came with a 12 x 14 and I switched to a 12 x 13 which was listed on the hull card.
Have not thought about trying a 12 x 12 but it may me get to 3,000 RPMs. Also getting my distributor checked over the winter as I have a pinging problem under load above 2,400 RPMs.
Our 1930 Zoomer came with a little propeller and we purchased a bigger one for tubing with the kids. I troll for Kokanee with the little prop and I also have to fill the petrol tank with $6.00 per gallon clear fuel more often. The bigger prop makes the boat go faster, which my wife hates.
Yep. That’s what we got.
Greg’s boat at 3100 is running a slip of about 15% (has little to do with overall propeller efficiency, BTW). That is a reasonable number. It will be interesting to see what STINKY’s actual speed is.
STINKY had a design displacement of 1750 lbs, but is obviously heavier due to the fiberglass covering. Beam 5′-8″ Depending on the model the 17 Deluxes had a beam of 6′ to 6′-4″. Displacements are probably close to what STINKY is today. So I would expect the boats to run very close to each other with same HP.
One more point, I know my Naval Arch side is showing thu, it is actually harmful for an engine to be over propped, i.e. not achieve specified WOT RPM. You ae operating the engine at a much higher load factor. A boat should be propped to achieve the engine manufacturers specified WOT. As I understand these engines are rated at 3200 RPM. 3100 is a reasonable number. Also, I am assuming these are direct drive no reduction gear. If not the numbers don’t make any sense.
My CC Deluxe is a 1947 post war. I do not know the exact beam within 4″. My tach calibration could also be 100 rpm off.
Clearly in the photo of the three props the shiny one must be the best!