Prop for E30 Plus

[Rhicke]

I am buying a 1980 E30 Plus with the 16 hp Universal. Seller is providing a new prop at haul out but I'll have some input on the selection. It will not be a folding or feathering prop. I'd thing a two blade would be better to limit drag. Any suggestions as to what works well?
Thanks,
Robert

 

[mherrcat]

Sorry for a slight hijack, but I would also like to hear what the optimum prop is for the 30+ with a Universal M18 engine. I have a suspicion that the prop on my boat may not be ideal. It is a three-blade fixed, marked: Michigan 13 RH 9. There is also a 10 02 marking on it that I assumed was a date.

 

[Frank Langer]

I have a two blade Varifold folding prop on our E30+ (I know you're not considering a folding or feathering, but the numbers may still be of interest) and it's numbered 13RH9. However, this is on the M-20 5416 16 horsepower universal engine, not the 18. It's reassuring that we're pretty close on the numbers.

This prop works pretty well on our boat. I usually motor at about 5.8 - 6 knots, which I estimate is about 80% of engine top speed (engine manual says to run at about 80%, but I don't have a tach, so I do it by sound/feel). At top speed it would likely go about 6.8 - 7 knots. I do get some port prop walk in reverse, which can be annoying, but I think that's normal. Otherwise, it has good speed and responsiveness in reverse as well.

Frank

 

[ted_reshetiloff]

Frank is probably pretty close but you may try consulting the folks at Michigan Wheel directly if no one else chimes in here. They can often suggest a diameter and pitch based on input from you. May need a few measurements from the boat too. Ideally you want the prop that allows the engine to reach maximum suggested RPMS per the manufacturer. Most universals thats around 2700-2900 RPM. If you are not getting there with a clean bottom and prop than you are probably over pitched or have to large a diameter. If you are getting to 3k or more you are probably under pitched or too small diameter.

That being said I have faith that someone with your boat will chime in here soon. This place is amazing for stuff like this...

 

[Frank Langer]

Ted, the problem is that while the specs for the universal 5416 (the most common engine on the 30+ boats, I think) call for 2800 max RPM, most of these boats came without a tach, so there is no easy way to know if we are at the RPM, as per your above post.

Therefore, unless someone has a better idea, I think the best we can do is to temporarily move the throttle to full open, and then pull it back to what feels like about 80%. At that point, I think the boat should be going about 5.8 -6 knots.

I know one can get laser tachs and other similar technology, but most of us don't have access to that stuff.

Frank

 

[ted_reshetiloff]

Dont need a laser tach, you can get a tach for diesel for <$100. You could always be a litttle dishonest and hook it up do your test and return it to Westmarine, but thats not nice. So nobody with a 30+ has a tach?

 

[mherrcat]

No tach here. If I had one I would use the method Glyn mentioned in another thread to evaluate my prop, although I have never seen a "sustained" RPM figure for the Universal M18. In the engine documents area I believe the maximum RPM listed for that engine is 3200.

Just checked the engine documentation and there is a section that mentions "the average cruising speed for a sailboat installation is about 80% of the maximum engine speed obtainable, to acheive hull speed." So I guess the "sustained" RPM would be about 2560.

 

[Frank Langer]

Mark, you mentioned in a post above that you have a suspicion that your prop may not be ideal. Are you having problems with your 13 RH 9 prop? Are you considering any alternatives? Do you have access to a prop shop that can provide professional advice?

The previous owner of our E30+ was very diligent in maintenance and also raced the boat a bit. I think it's quite likely he did alot of research before having the Varifold folding prop 13RH9 installed. It seems to work pretty well.

Frank
1984 E30+

 

[Loren Beach]

More Blades

Having used a two-blade fixed for a couple years, and then a low-drag featherer for over a decade, and now a three-blade fixed "sailor" prop for a year, I can say with some certainty that the drag from the fixed props is very similar. You lose about a knot under sail in all winds.
There is somewhat less vibration with the three blade fixed over the two, and the thrust is a lot more noticeable.

If given a choice of the less-expensive fixed-prop choices, I would go with the three-blade.
And don't let anyone befuddle you with "racing" explanations or exposition, either. After all, if you enter a race, you get a rating allowance for having a fixed prop, and of course a faster rating # if you have a featherer or folder.

**Remember: For maximum sustained befuddlement, just keep reading everything on this site!


Enjoy that handsome new-to-you Ericson.
Strangers really do walk up to Ericson owners and compliment their boat!


Loren

 

[mherrcat]

I'm not having any particular issues to speak of, just don't know for sure if I am getting the most from the current engine/prop combination. (More curiosity than anything else.) Not sure if there is specifically a "prop shop" local to me but I'm sure the engine shop housed at one of the local boat yards could look into it...for a price. The previous owner of this boat was NOT very diligent about maintenance and repair. Things have improved considerably on my watch...

 

[Frank Langer]

Yes Mark, I can see from your posts over the last while that you are catching up on maintenance. These boats are worth the effort!

Frank
1984 E30+

 

[eknebel]

e 30+ PROP

I realize I am replying to a old thread, but since I have some answers for Ericson 30+ props, here goes:
I just had to replace the original 12x12 RH fixed 2 blade prop that came with the 5416 engine when I lost one of the blades. Noticeable vibration when the blade came off, but not as bad as you might think. There was visible long term corrosion in the cracks where the blade left the hub, I guess one too many crab pots...
I replaced it with a martec 13x12 RH 2 blade folding prop and have gained about a half knot at 2100rpm, cruising at 5.8 knots in calm water. Reverse is similar, a little weaker, with some cavitation with full reverse, and about the same amount of prop walk. Under sail is harder to compare, but the boat does seem faster, especially in light air. I am convinced of this increase in speed, the admiral, however, just rolls her eyes!

I scuba dive, so I elected to replace the prop with the boat in the water. It took about 2 hours start to finish, with most of the time spent removing the old cotterpin and prop. Using the puller below, I still had to use 2 hammers and hit the hub from both sides to get it free. I wanted to use blasting caps like are used on larger boats, but once again, the admiral was the voice of reason. Another tool for the collection, one I hope not to use again!

Walter Machine Company NO1 Walter Machine Plate Puller
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