[Bruce More]

Does anyone know the prop clearance for the ranger 29. I am trying to order a new prop to get the maximum speed out of my engine and need to know the maximum effective clearance to optimize the best performance.
Thanks for any comments
Bruce

 

[Faster]

I wouldn't base you diameter on how much clearance you have.. Size the prop based on hp and displacement and then be sure it fits with room to spare. It's possible to be "too" close to the hull. Seems to me a prop around 12" D would be about max for that boat.

 

[christian.hess]

x2 bud

 

[christian.hess]

plus you said max speed so that would mean bigger picth...smaller prop

usually people want more torque for stuff like dropping and anchor and slow speed control so what they do there is go more blades, less pitch(flat blades) on a nice sunflower flat big prop this also ups the rpm range and your cruising rpm goes up quite a bit...good for engine as less wear and tear but you do use more fuel even though the engine is not straining as hard

its a delicate balance honestly...you can have an engine struggling with a bad prop or in happy high rpms...but using a bit more fuel...I prefer the second option...happy rpms less load on the engine

usually when people say they want more speed in fact they want more overall power...overall power can losely be translated to a bigger prop

LOSELY as you can go overboard and strain the engine more than with a small albeit badly pitched prop

if what you want is more ueable power the best thing you can do is get more blades(at the cost of more water resistance when not running i.e drag) and slightly flatten the pitch to get better rpms.

small engines like this as they are less torquey than bigger engines so upping rpm range has the beneifit of keeping momentum up....that does mean however that if you really need to jam the throttle you wont notice such a big difference as with more blades flatter pitch in essence you are losing

TOP SPEED

hope this didnt confuse us too much

probably did

sorry

 

[Alex W]

I wouldn't base you diameter on how much clearance you have.. Size the prop based on hp and displacement and then be sure it fits with room to spare. It's possible to be "too" close to the hull. Seems to me a prop around 12" D would be about max for that boat.

My very similar sized Pearson 28-2 has a 16" prop. That is what it originally came with (2 blade, 16" diameter, 10" pitch). When I switched to a Campbell Sailor they suggested a 14" prop, so I used that for a while. I upgraded to a feathering prop about a month ago, and Featherstream/Darglow recommended going back to a 16" prop.

12" was common for boats that originally came with an A4 (like the Ranger 29), but I think 14" to 16" is appropriate for higher torque/lower RPM diesel motors if one can fit.

I'm not saying that just because my Pearson 28-2 will fit a 16" prop that a Ranger 29 will as well. I'm just saying that it is worth finding out what will fit.

Is there a Ranger-specific mailing list? You might be able to find out exactly what fits over there.

 

[Faster]

My very similar sized Pearson 28-2 has a 16" prop. That is what it originally came with (2 blade, 16" diameter, 10" pitch). When I switched to a Campbell Sailor they suggested a 14" prop, so I used that for a while. I upgraded to a feathering prop about a month ago, and Featherstream/Darglow recommended going back to a 16" prop.

.......

Wow.. that's a surprise. Not much smaller than our 40 footer used.

The OP hasn't stated the engine type and I was thinking A4...

 

[Alex W]

I should have added that my boat has a Yanmar 2GM20F with a 1:2.62 final drive ratio. The three props that I've used are:
* Michigan Sailor 16x10P 2-blade (original prop to the boat)
* Campbell Sailor 14x8P 3-blade
* Featherstream 16"x9.5P 3-blade feathering

I think the Campbell Sailor (which has an aggressive airflow shape on the blade) acted like it had the most pitch, even though it was technically the least. I went about 6 knots at 2750rpm with that prop. With the Featherstream it seems like 2900rpm gets me 6 knots, but I haven't had it long enough to have used it in a variety of conditions.

 

[christian.hess]

a4´s have notoriously small props with medium picth

my last boat had a plastic prop for petes sake and did fine

it was a small 12 incher...atomic4´s do however run at a higher final rpm than diesels.

My previous engine before that was also a 2gmf20...but on the boat it was one a big heavy wooden boat it had a nice 2 blade bronze low pitch prop...much bigger and flatter than the atomic 4 prop.

part of what I was trying to explain before...but did a bad job of doing so

my current boat has a 2 blade 12 incher too...pitch is 9 I think...it was a palmer p60 engine

almost same spec and characteristics as the atomic 4.

 

[GMiller]

He has gone from an A-4 to a 13.5hp Beta diesel, but has had issues with being able to achieve hull speed with recommended props, even after some reworking of a 3blade Campbell sailor. A prop calculator is recommending a larger diameter prop, thus the need to determine the prop clearance, so we can have a couple on hand when he pulls next week.

Hiya neighbor!