E-35 mark II Prop Size and pitch

[seabreeone]

Last owner installed a 14 RH 14 2 blade prop on my boat. a Ericson 35 mark II. I have a Yanmar 20 HP diesel. I want to change out props to a another 2 blade or maybe 3 blade. If you have a Ericson 35 Mark II and know your prop diameter and pitch please share it with me. So I can make a decision on what to replace with. I see many post on replacement of props on other size Ericson's but not many on the 35 Mark 3. I contacted a few prop manufactures and they told me the 14 14 I have, is not the proper prop for this boat and engine. and recommended a few others. What do you have?

 

[Loren Beach]

While you refer to your model as a mk 3 in one place, it sounds like you have a Mk2.
While I am ignorant about the right size prop for that model, I do know that putting a three-blade fixed "sailor" prop on our boat gave us a measurable speed increase under power at recommended cruising rpm's for our engine. More blades seem to be lots better- the area is important especially when motoring against some chop.

Loren

 

[seabreeone]

Mark 2

Yes my boat is a Ericson mark II. typo, Thank you for catching that. I have seen threads on the Mark 3 boats but not many on the Mark 2. With my transmission it is recommended that it stays in neutral when sailing. Or to have a shaft brake installed to keep shaft from spinning and to be able to keep trans in Neutral. One person has told me that with the 3 blade it will spin faster and louder when sailing? I am trying to weigh all the issues. I don't mind installing a brake on the shaft, If the end result is more motoring speed and less vibration. or as my dock neighbor said install a small generator on the spinning shaft to charge the batteries??? At first that sounded like a crazy idea to me, but it might work? That might be a new thread??? Thank you all for you help......

 

[mfield]

Spinning shaft

Generally the recommendation is to put the transmission in reverse. The packing gland will leak a little if its spinning and it will turn over things in the transmission.
Mike

 

[Loren Beach]

Yanmar might be different....

Most of us have Universal diesels with the usual Hurth transmission. Their manual advice calls for putting their transmission in reverse while under sail to lock the shaft (i.e. it will not turn and therefore you will experience prop drag). They also say that leaving it in neutral is ok, but the sound of the shaft turning while you are sailing is irritating. True on all counts for our boat.

Yanmar requirements are likely different, and the only way to know for sure is to read the manual. So, really, "rtfm"...

Seriously, if you search on line there are manuals for all of these hard working little engines. If the former owner did not leave the paperwork, look on the engine itself for the identifying model type.

Cheers,
Loren

 

[Alan Gomes]

For Yanmar it is NEUTRAL

See attached .PDF

 

[seabreeone]

Trans and props

My yanmar Manuel. It says do not put Kansaki transmission (cone type) in gear. forward or reverse when sailing or serious damage will occur and void Yanmar warranty. It has been out of warranty for years but I had it rebuilt last April, $2400.00 not cheap at all. the parts alone, bearings, clutch plates. etc. all fit in a med zip lock bag and they were $1100.00 and the rest labor and tax . We just returned from a trip her in So Cal. a bit over 80 miles and I could not believe the great fuel mileage. we wanted to run motor as much as possible this year. So We listen to the noise and motor sailed with the jib up only.We made 6 to 7 knots per hour with engine running about 60% of wot.(I don't have RPM gauge) and burned only 1 gal of diesel every 3-1/2 hours. For that reason my 14 14 prop seems great, but I need more power if sails are down. wot only gives me 5.5 knots, with this current prop. The hull speed works out to 6.5- 6.8 on paper....

 

[Alan Gomes]

My yanmar Manuel. It says do not put Kansaki transmission (cone type) in gear. forward or reverse when sailing or serious damage will occur and void Yanmar warranty. It has been out of warranty for years but I had it rebuilt last April, $2400.00 not cheap at all. the parts alone, bearings, clutch plates. etc. all fit in a med zip lock bag and they were $1100.00 and the rest labor and tax . We just returned from a trip her in So Cal. a bit over 80 miles and I could not believe the great fuel mileage. we wanted to run motor as much as possible this year. So We listen to the noise and motor sailed with the jib up only.We made 6 to 7 knots per hour with engine running about 60% of wot.(I don't have RPM gauge) and burned only 1 gal of diesel every 3-1/2 hours. For that reason my 14 14 prop seems great, but I need more power if sails are down. wot only gives me 5.5 knots, with this current prop. The hull speed works out to 6.5- 6.8 on paper....

Just curious: which engine/transmission do you have?

 

[seabreeone]

more prop

If anybody has played around with different prop sizes and pitches please if you can share your findings with me I would really like to hear what you found out...Thank you..

 

[seabreeone]

engine and trans.

I have Yanmar 2qm20 Kansaki trans 2.14 ratio 1" shaft.

 

[Glyn Judson]

Prop size experimenting.

All, What I'm about to share deals with the Yanmar powered E31. I was way over propped (squatting under full power with soot build up aft of the side exhaust when we bought our E31, hull #55 fitted with a Yanmar 3GMF with Kanzaki 2.61:1 transmission. I couldn't even get close to the 3,700 RPM's, factory recommended top speed needed, as proof of proper pitch and diameter, etc. After three iterations including what I started with, I ended up with a 13 X 12 1/2 X1, 3-blade and was able to get 3,700 RPM's right on the nose. Mind you, that's not to say that these engine should ever be run continuously at that speed, it should be at least 80% or less of that. Another E31, hull #06, owner complained to me that his identical power plant and transmission to mine couldn't keep up with a mutual friends E31, hull #19 with the identical set up you have, a Yanmar 2GM20F, and his (hull #19) eventual prop numbers ended up at 13 X 12X 1 RH, 3 blade at my recommendation based upon my own experience. I should mention that he was then able to get 3,700 RPM from his engine. I don't recall what my hull #06 friend started out with but at my suggestion and against the recommendations of two separate prop shops local to him, I asked him to trust me and use my numbers. Again, he got 3,700 RPM's precisely spot on and could finally cruise with hull #19 and not lose ground. Add to that, the owner of E31, hull #44 essentially has the same engine, a Yanmar 3GM30F as I do and copied my numbers. I think he is happy with the result. So there you have it, a difference between four E31's of 1/2" in pitch on one of them and we're all zeroed in. Will that work for your longer boat, I just can't say because I'm not an expert at anything including prop sizes. Here's hoping that my experience will aid you in selecting a better pitch for your prop. Glyn Judson, E31 hull #55, Marina del Rey CA

 

[Glyn Judson]

One mote data point.

All, Another E31 owner, hull #22 reports satisfaction with the same combo as mine, using 13 X 11 X 1, 3-blade, RH Glyn

 

[Glyn Judson]

Oops!

Sorry, I misread you engine model, all my numbers might not apply. There is a vast difference between the QM and the GM engine. I don't know the top speed of your engine. Sorry for the error, Glyn

 

[TakeFive]

All, Another E31 owner, hull #22 reports satisfaction with the same combo as mine, using 13 X 11 X 1, 3-blade, RH Glyn

My E31I has 3YM30 w/ Kanzaki KM3P 2.61 trans. Way over propped at 15X14 (3). Prop calculators suggest 15X11 (3).
I probably won't change it because I get hull speed going through inlets (very necessary) but sacrifice ability to run engine at WOT.
Diesels should be periodically run at wot IMO but pulling props is iffy proposition even with puller, torch, sacrificial goat.

 

[Glyn Judson]

Thanks for the information, I added it to my data base. Yours is one of three E31's so powered. Glyn