Atomic 4 To Universal Diesel REpower Prop question

[DeFranco84]

Hey! Just toomk out the wrapping up a Repower on my Ericson 35 mk 2 I took out The atomic and put in a Universal 25 xp. I currently have a 3 blade prop I belive 12x7. Can
you recommend a new prop for tge new engine? What size? Someone told me 12x14 but the pitch sounding large to me

 

[67rway]

Data Point

I presume someone with a 35 mk2 will chime in, but as a data point our M25XP O34 seems well suited with her 15x10 FlexOFold 2-blade prop.

 

[frick]

From A4 to diesel

Hey! Just toomk out the wrapping up a Repower on my Ericson 35 mk 2 I took out The atomic and put in a Universal 25 xp. I currently have a 3 blade prop I belive 12x7. Can
you recommend a new prop for tge new engine? What size? Someone told me 12x14 but the pitch sounding large to me

Here in an online tool that works
https://www.vicprop.com/displacement_size.php...

My E 29 with the A4 turned a 12x 12 left handed
With the Yanmar 2Gm20 f I turn a 14 by 12 right handed

in increase in the bite is because the A4 spring the prop at twice the speed of the diesel.


Rick

 

[eknebel]

When I was replacing my prop on my E-30+(16 hp universal 5416) , the man with the phd in naval architecture advised me that on displacement hulls, it is the engine that determines the prop, not really the boat. The boat is a consideration for prop size with clearance of the hull and rudder, but the engine determines the workable combination of pitch and size. I ended up with a Varifold 2 blade Shaft Propeller 14 x 11, which didn't really increase top speed(limited by the hull waterline) but did increase thrust, which helps motoring upwind. At idle, in calm water, it goes 2 knots, which is a little fast for searching for a slip at a new marina.

 

[Alan Gomes]

When I was replacing my prop on my E-30+(16 hp universal 5416) , the man with the phd in naval architecture advised me that on displacement hulls, it is the engine that determines the prop, not really the boat. The boat is a consideration for prop size with clearance of the hull and rudder, but the engine determines the workable combination of pitch and size. I ended up with a Varifold 2 blade Shaft Propeller 14 x 11, which didn't really increase top speed(limited by the hull waterline) but did increase thrust, which helps motoring upwind. At idle, in calm water, it goes 2 knots, which is a little fast for searching for a slip at a new marina.

If by "engine" you are including the engine and transmission as a unit, then I think this is accurate. The transmission gear reduction has a direct effect here.

 

[eknebel]

You are correct, thanks for the clarification.