e29 Propeller Selection

[jamin]

We have a e29 that has been refit with a Universal m25xp diesel. The gearbox has a reduction of about 2:1.

We haven't verified completely, but it appears that we have the original 12x7 prop standard with the atomic 4. This gets us about 4.5kts in calm conditions...ugh.

After some research, it seems the m25 is happiest with about a 15" prop. On our e29, there is only about a 2 finger clearance from the blade tip to the hull with the 12" prop.

Performance propellers recommendation:
Get the largest pitch 12" (maybe 13") prop we can find and live with the difference. Also, go to a 3 blade if we dont mind the loss in sailing performance. They say the 3rd blade is equivalent to roughly an inch of diameter.

They also state there isn't enough rudder clearance to run their 'extendo' prop.

Campbells Recommendation:
we would recommend a
CS12x10x3/4 for your installation. This is a Campbell Sailer, three blade,
Right Hand rotation, 12" diameter, 10" pitch for a 3/4" shaft. This size is
recommended to give you a good cruising rpm and still have reserve for head
wind and seas. We have installed a number of propellers for the Ericson 29
and the better option is to stay with a 12" diameter due to the tip
clearance.



So, what do you guys think??

Also, do other e29s have 3/4" shafts??

Thanks in advance,
Jamin

 

[Randy Rutledge]

What prop

I installed a Flexofold 12-7 on my E-29 with the A4 you would need a 12-9 probably. The Flexofold rep would know what you need. The prop drives the boat much better than the two blade did forward and reverse. The boat also has better response from the helm and sails faster than with the fixed prop. Cost is high but the payback is great.

 

[jotte]

Flexofold

Randy,

How much clearance do you have on the rudder when the prop is folded? With the diesel and 2:1 reduction we need as much prop as we can fit, especially if we stay with a two bladed. Flexofold states:

• Unlike the general perception, even as little as 8-10 mm of free space between propeller and hull will be fine on most boats.<O</O
• Due to the nature of the propeller construction, folding blades are positioned further aft than a fixed propeller (see hub length) and thereby leave more space between shaft and hull.<O</O

My concern with going with a larger diameter which may work on hull clearance would be rudder clearance when folded.

Thanks Jim (Jamin's co-captain)

 

[Randy Rutledge]

Best I remember there was more than a couple of inches rudder to prop when folded. THis was a concern of mine with the 12" but there was plenty of clearance. I can check this weekend if I remember, it will be a measurement under water. You can call me at 770-710-9863 this weekend to remind me, leave a VM if I don't answer.

 

[jkenan]

Would changing your strut out with one that was slightly longer a viable solution? I don't know, and am asking. If this were viable, it would give you more prop clearance and help you maximize your options. Don't know if the steeper shaft angle would pose any problems.

Also, I've heard more than once that a 3/4 inch shaft is minimal at best. With the more powerful low-end torque produced by a deisel (as opposed to the A4, or a deisel with an undersized prop), you might want to consider getting a bigger shaft, which would require a new strut anyway.