Prop Specs

[vmaks]

FRESH WATER ONLY-GREAT LAKES.....1988,Pearson 31-2, fitted with an obsolete(meaning= Martec told me they haven't made that prop in 25+ yrs and they really don't carry parts for that prop anymore. That also means, this prop hasn't been serviced except my yrly request to grease the zert since I purchased the boat 4 yrs ago) 3 blade folding Martec prop. The previous owner over propped the pitch as I was only able to reach 3200rpms under load, 3400 continuous/3600 1 hr called for. I found a 2 blade bronze hidden away in the boat, obviously o.e.m. item as it was stamped the yr of the boat production, 16x11. I did dial down the pitch of the Martec to increase my rpm's. I don't mind the prop, it came with the boat, except I have noticed I lack command of the boat at times. It's a little slow to respond and makes me feel like we are accelerating thru "thick water " until we get going(hence why I think the p.o. increased the pitch). What we did notice,especially compared to our old O'Day 2 blade prop with a 11 jo Westerbeke, was that I lack controll with any wind as I come in/out of a slip. I started to dread going out cuz that meant I had to eventually come back into a slip. My confidence is veering and my slip neighbors can't understand the issue, no matter what method I try with this boat. To add issue, this year the prop did not slip into the forward position 2x's as I was backing out of a slip into a narrow fairway and the wind was working against me....even after I did the neutral pause before going into forward. It makes me pause...is this prop showing failure signs, is this the rt prop? I asked Martec how to pitch this back to factory settings and attempt to match the settings needed for my boat. B/C this is outdated, I got no concrete answers except to trial the ram's til I get it rt(mind you, our water is in the 60's and I do not plan on going under the boat to attempt this task. I also can not justify haul/splash til I do get it rt)
Our engine is a Yanmar 2gm20f, gearbox Kazaki 2.62 reduction.
So, why am I asking for advice. We just finished a 3 wk trip and upon checking the oil before the take off to a new port we notice how thirsty our Yanmar is for oil....6oz,8oz,16oz,you get the idea. We dropped down from 2800 rpm to 2500 and she was less thristy, but yet,thirsty for oil. Where we were had ZERO diesel mechanics so we obliged to her thirstyness until we got to our home port where we could do a phone visit with our Yanmar mechanic. Haul-out is soon, we will do a compression check to decide what steps to proceed. For me, when I head bk to the boat I will check the air filter. I am hoping this engine is not requiring an overhaul from 7+ yrs of being over propped(which is what Mac Boring told me I needed as I was looking.for advice how to limp bk home from my trip. BTW...she ran just fine except.for her thirsty behavior. MB scared me,told me by boat.would/could race out of control before it just died on me). My best guess, the boat is 33 yrs old @ approx 100 hrs/yr= max 3300 engine hrs( just a guess, these boats did not come with an hour meter til I put one on 2 yrs ago). I have dubbed her my COVID BOAT....valve tap, soot on the transom, smoke only upon start up, pissing plenty of water and very thirsty for oil. Otherwise, .3-.4 gal/hr burn rate of fuel and she runs smoothly at 2500-2700 rpm.
So,back to the prop question....once I get all of my engine issues figured out, I want the proper prop on the boat so we do not stress out the engine again, something different since we are struggling with the Martec. We are fair weather sailors who are not too proud to motor sail if it means making 6 knts vs the 3.8 or 4 knt on a long crossing day(dog on board,plus, those long days interfere with happy hour). Common for us might be chop with headwinds up to 3-4' square waves. We sail Mem Wkend thru Labor Day Wkend, we want to enjoy the boat but get outa Dodge when we see high wind prediction coming down upon us or a storm. Honestly, I think we are done with mechanical props and want to simplify. Do I put that 16x11 o.e.m. back on, do I have the 16x11 tweeked to a 16x10, do I get it tweeked to a 15x10? ANYONE with my boat type have suggestions? I spoke with Mich Prop, they suggested a 3 blade 15x10. I hate to spend that kind of $ only to find that the prop is wrong for my boat-engine-gearbox. I am considering all suggestions, other than $3k on a fancy prop.
Thanks

 

[sail sfbay]

A few questions you will need to answer: 1) what type of prop, fixed or folding/feathering, do you want to install, 2) number of blades, 2 or 3, 3) do you care about any prop drag while sailing, 4) what is your budget? Once you decide, go shopping and provide the prop supplier with your engine/ transmission/shaft specs, i.e., Yanmar 2gm20f, gearbox Kazaki 2.62 reduction with a goal to select a prop diameter and pitch and that will maximize your boat's performance, while allowing your engine to operate in the recommended rpm. range. You do not have to spend $3000 on a fancy propeller. Last time I purchased a propeller it was considerable less than that.

 

[jssailem]

Vmaks when I first got my boat I thought the builder and former owners must know what prop to use.

Powering about the Puget Sound I wondered why am I riding like a wake board boat in the water the exhaust 12” below the waterline? Why is there a big black diesel stain on the transom?

When I pulled the boat for bottom job and repair the reason was evident.

Those big ears and the pitch were dragging the stern down trying to bite the water.
I sensed there had to be a better idea but the power boat side of a big sailboat was not my strength. Diving into the way prop design has evolved over the past 40 some years I learned about thurst and drag of the blades.

I weaved my way through the many folding blade/rotating blade designs and their associated costs. I sailed with friends who chop water with folding props.

My desire was a prop that propelled the boat at hull speed using 80% of the available power (thus having some reserve to punch through chop and wind when needed). Additionally I did not want to further compromise my sailing experience with the prop.

This led me to finding the Campbell Sailor made by WestbyNorth out of BC Canada. The engineer Kelsey took the engine, transmission, shaft, and boat specs plus the goals I wanted to achieve and blended them into this prop.

I am very pleased with the results. I have the power I wanted, my engine seems to preform much better. No more diesel stains on the transom. I experienced a 1.2 knots per hour improvement under power. Less prop walk which means I can’t use that tool to push the boat about like I became accustomed. All changes involve compromise. There is no more prop noise when sailing. I sense minimal drag from the prop.

I am pleased with the results of my prop change. I would encourage you to consider my path.

 

[heritage]

I have the same engine and transmission on my Hunter 27. It has a 3 blade 13x11 prop that allows the engine to rev up to 3400 rpm and exceed hull speed. Plenty of low speed torque but a lot of prop walk in reverse.

 

[Scott T-Bird]

I suppose it is possible that some of your engine troubles could have something to do with being over-propped, but I doubt it. You say it tops out at 3200. It could be topping out there because of the need for an overhaul and not necessarily because of the prop. I doubt your oil consumption has anything to do with the prop. But, assuming that you aren't suffering any leaks and the oil consumption is based on the engine feeding on it, I suppose that is why MB is bringing up runaway engine. 3200 is probably significantly higher rpm than most people will ever run their 2GM20f while cruising. I would not have played with the pitch during mid-season if getting in the water is a limiting factor. Now you seem to have control issues and lost all confidence in the prop. It seems that you are piling all of the engine symptoms on your prop and turning it into a snowball running downhill. I think that I would have finished the season and addressed each issue separately. It doesn't sound like it really needed immediate attention. You probably do need an overhaul on your 33-year old engine. Some people will tell you that they run forever, but they aren't going to without some specialized care from time to time. Then, get yourself a new prop since you don't have confidence in the one that came with the boat - perhaps it has seen it's best days. It doesn't really do you any good to hang on to it, if you lost all confidence.. Get some professional assistance in selecting the right one. I don't think it does you any good to pile all your woes on just one factor. There is just no way of knowing for sure. Sort out the problems, address them individually, and move on with your sailing! Why not simply address them in the off-season?

 

[MitchM]

wow, Vmaks, would you mind sharing the name and contact info of the person at mack boring who was actually willing to talk to you about your issues ? the guy who replied to my email 2 weeks ago just told me to ' call my local dealer ' with a couple phone numbers and a yanmar map link. in the olden days, mack boring the yan east coast distributor, out of union city n j., had great mechanics always willing to spare a few minutes of advice . their reply to my recent inquiry was an email telling me to 'contact my local dealer ..' since i'm likely in the market for a new engine (westerbeke? nanni? torqeedo? volvo ? yan ysm15? ) or a rebuild of my yan, mack boring's 'customer service' left a whole lot to be desired.

 

[Daddio417]

I have the same boat with the same engine, fewer hours. I have the original two blade prop and make over 6 kts at 3000, run her at less. I don’t have any serious issues at the dock other than changing direction from fwd to aft doesn’t always happen as quick as I would like ( or need in a following wind). My engine is not consuming any noticeable amount of oil, but my rear gets a little sooty, not a character flaw I hope. I think the two blade will serve you well, albeit your advancing hours may require attention, I am having my injectors serviced year end.

 

[fstbttms]

...fitted with an obsolete(meaning= Martec told me they haven't made that prop in 25+ yrs and they really don't carry parts for that prop anymore. That also means, this prop hasn't been serviced except my yrly request to grease the zert since I purchased the boat 4 yrs ago) 3 blade folding Martec prop.

I'm confused. Martec never made a 3-blade folding prop nor ANY prop that had zerk fittings.

 

[vmaks]

I suppose it is possible that some of your engine troubles could have something to do with being over-propped, but I doubt it. You say it tops out at 3200. It could be topping out there because of the need for an overhaul and not necessarily because of the prop. I doubt your oil consumption has anything to do with the prop. But, assuming that you aren't suffering any leaks and the oil consumption is based on the engine feeding on it, I suppose that is why MB is bringing up runaway engine. 3200 is probably significantly higher rpm than most people will ever run their 2GM20f while cruising. I would not have played with the pitch during mid-season if getting in the water is a limiting factor. Now you seem to have control issues and lost all confidence in the prop. It seems that you are piling all of the engine symptoms on your prop and turning it into a snowball running downhill. I think that I would have finished the season and addressed each issue separately. It doesn't sound like it really needed immediate attention. You probably do need an overhaul on your 33-year old engine. Some people will tell you that they run forever, but they aren't going to without some specialized care from time to time. Then, get yourself a new prop since you don't have confidence in the one that came with the boat - perhaps it has seen it's best days. It doesn't really do you any good to hang on to it, if you lost all confidence.. Get some professional assistance in selecting the right one. I don't think it does you any good to pile all your woes on just one factor. There is just no way of knowing for sure. Sort out the problems, address them individually, and move on with your sailing! Why not simply address them in the off-season?

Thanks for your reply,appreciate the insight.
1. The prop was adjusted last year prior to our launch season in May and has been used this year with the new adjustment. I am seeking info from the forum as I prepare for this off season decision making re the boat, October thru May. I ask about the prop b/c I was very surprised to find out that the existing prop, Martec, has not had this particular prop in service for 25 yrs(per Martec's words themselves using the actual # from the paperwork) and they are confident that parts are no longer available for the purpose of reconditioning it. My thoughts....maybe I seek a modern day prop and move on since the present one is outdated. The rpm #'s I provided are those prior to the adjustment. Once adjusted and used this yr, we THOUGHT we were good since the boat was reaching hull speed at/near 2600, we were able to reach the required rpm's for the test phase under conditions of light to zero wind. Our concern was established when we started having backing troubles and our biggest concern was what we thought was an extreme thirst for oil in a short number of hour run-time.
2. Our immediate concern was b/c we were in the middle of a trip that required us to sail back to our home port thru headwinds in a shipping channel and 3-4 days away from a diesel mechanic(we got bk safely). Now that we are back, we are about 1 month away from her being put to bed for the winter( per mechanic,he said the engine will be fine for the rest of the summer as long as I keep oil in it.....reassuring after the m.b. conversation). Our plan of attack,per discussion with our Yanmar mechanic...get her into storage,do a compression ck to analyze the next path of service required, i.e. injectors, overhaul,prop,etc. NOPE, no visible oil leaks in the engine compartment, just soot on the stern and she does purr, even if thirsty for oil, thru 2800 cruising. She does have the valve tap sound that my old Dodge Duster had prior to service but in fairness, my old Universal also had that valve.tap sound. IFFFF I need an overhaul, I would like to be educated on the proper prop to be fitted on an engine I just spent $ on to fix. If the compression is fine and something less needs to be addressed, I still want a prop on it that is not 25 yrs old and can not be serviced.
3. I found the original prop stored away in hiding in the boat, Day Sailor 6/1986, 2 blade, bronze, 16RH11. We considered having it serviced,even lessening the pitch to 10 and try it for 1 yr, the summer of 2022, POST engine repair/analysis. After reading about fixed 2 blade props I considered modernizing the blade to match our specs. I called Michigan Prop,they made a suggestion for a 3 blade fixed but suggested not buying a new prop and work with the 2 blade original I found stored away. They suggested a company located in Michigan which would adjust my 2 blade original prop should that be the path I take vs buying new one. I called the referred company, they really don't deal with sailboat props which made me consider seeking more info re props for OUR SPECS,PERTAINING TO SAILBOATS,ETC. not power boats. I just want to do the right thing and have a prop that does the job, doesn't stress the engine and one which will not require me to haul her out/in til the adjustment is perfect($$$$ for that task). I am a cruiser in the Great Lakes, just enjoying the boat-water and feel secure in my boat that gets me thru the rough patches of weather as the storms come upon us quickly.

Again, thank you for your previous response. I hope I clarified any misunderstandings re my "plan of attack" this off season.

 

[vmaks]

wow, Vmaks, would you mind sharing the name and contact info of the person at mack boring who was actually willing to talk to you about your issues ? the guy who replied to my email 2 weeks ago just told me to ' call my local dealer ' with a couple phone numbers and a yanmar map link. in the olden days, mack boring the yan east coast distributor, out of union city n j., had great mechanics always willing to spare a few minutes of advice . their reply to my recent inquiry was an email telling me to 'contact my local dealer ..' since i'm likely in the market for a new engine (westerbeke? nanni? torqeedo? volvo ? yan ysm15? ) or a rebuild of my yan, mack boring's 'customer service' left a whole lot to be desired.

Sorry, I can't remember the guys name in which I spoke to. I know he was trying to be informative but put the fear in me considering we were in a very small port, far away from a diesel mechanic or parts and still had to sail under the Mackinaw Bridge thru a shipping channel and thru a reef area to get to our home port. Everytime I have spoken to them they seem to have been informative. Sorry your experience was bad.

 

[vmaks]

I'm confused. Martec never made a 3-blade folding prop nor ANY prop that had zerk fittings.

I had the paperwork with the model #, they knew exactly what prop I had. They also said it was obsolete, by 25 yrs. I called them last yr and this year, spoke to them myself Please see pic attached for proof of pic. Martec 3 vlade feathering prop, 3000 series which they don't make. And yes, it does have a zert fitting...I also have that info and zert adapter as well as directions pertaining.

I'm confused. Martec never made a 3-blade folding prop nor ANY prop that had zerk fittings.

 

[fstbttms]

I had the paperwork with the model #, they knew exactly what prop I had. They also said it was obsolete, by 25 yrs. I called them last yr and this year, spoke to them myself Please see pic attached for proof of pic. Martec 3 vlade feathering prop, 3000 series which they don't make. And yes, it does have a zert fitting...I also have that info and zert adapter as well as directions pertaining.

These are likely Slipstream and Autostream props, for which Martec acted as a dealer. I can assure you they did not manufacture them.

 

[vmaks]

These are likely Slipstream and Autostream props, for which Martec acted as a dealer. I can assure you they did not manufacture them.

So....does this mean that ANYONE who will service a feathering prop will be able to service this prop? I did look up both of the mentioned props you mentioned, one of them is definitely a modern day versions of our above prop.
A. Do you think a 25 yr old prop is worth just replacing vs reconditioning due to new technologies?
B. Should I both with having the 2 blade, 1986 prop put back on for 1 yr?
I realize that your opinion is just that and the ultimate decision is mine. Until this boat I was under the thought that a prop is a prop and since it came with the boat I figured it was pitched properly,until.....I was u able to reach the needed rpm's. So,your opinion does matter.

 

[fstbttms]

So....does this mean that ANYONE who will service a feathering prop will be able to service this prop?

I suspect that any prop shop experienced in dealing with feathering or folding props could do the work. That doesn't mean that ANY prop shop could do it however.

A. Do you think a 25 yr old prop is worth just replacing vs reconditioning due to new technologies?

That would depend upon the cost of reconditioning. If you are going to spend a couple thousand repairing a 25-year-old prop, it seems like buying a new one for $3000 might be the way to go.

B. Should I both with having the 2 blade, 1986 prop put back on for 1 yr?

Not sure I understand what you are asking here.

 

[vmaks]

I suspect that any prop shop experienced in dealing with feathering or folding props could do the work. That doesn't mean that ANY prop shop could do it however.


That would depend upon the cost of reconditioning. If you are going to spend a couple thousand repairing a 25-year-old prop, it seems like buying a new one for $3000 might be the way to go.


Not sure I understand what you are asking here.

Re 2 blade prop.....we found the original 2 blade tucked away. $141 to recondition it or to decrease the pitch (in 1986 this engine called for a 16rh11, in 2021 this engine is calling for a 16rh10. However, after reading many comments there seems to be numerous dissatisfaction about converting bk to a 2 blade...vibration,lack of power, shaft noise,etc. I will call a few places today to see the cost of reconditioning the Martec, tho we are keeping an open mind about replacing. However, $ this yr seems to being allocated to solving the thirsty engine of oil issue and we were hoping to use one of our existing prop options for next yr. Thanks for the quick opinion.

 

[Scott T-Bird]

For a sailor, you sure are stressing over your prop and engine! And I thought I was overly concerned about engine performance! From everything you describe, I don't think you have a serious problem. First things first ... good plan to focus on the engine during the off-season. Check compression, fix the oil consumption issue with an overhaul, if necessary. Get your engine right this winter and worry about the prop for the next off-season. You don't need to spend any money on the prop this winter while you are focusing on the engine.

But what you can do is simply make a decision about the prop. Here are my thoughts:
1. You don't have a clear cut winner with either your obsolete feathering prop or your original 2-blade prop. Choose which one you want to use, which is more easily said than done. But don't spend any re-conditioning money on either. Most sailors would readily choose a feathering prop over a fixed blade prop for the simple reason that your sailing performance would be improved with the feathering prop. I suppose you might not be able to tell much difference between a 3-blade feathering and a 2-blade fixed, but I suspect that I would choose the feathering prop. Don't forget that you are a sailor, not a power boat enthusiast! (that's the reason the p.o. bought the feathering prop, btw).
2. If you decide to use the feathering prop, decide if you want to go back to the original pitch for better control or keep your current pitch for the optimal high-end rpms. It sounds to me like you had no issues with your prop until you freaked out about the top end rpm at 3,200. Perhaps your concern was touched off by the oil consumption. You don't really know that the 2 issues are related but it doesn't really matter now. You decided to dial in your engine so that will be resolved if all goes well.
3. I think you are over-reacting to the over-propped proposition! If you get 3,200 rpm and the control is the way you like it, just go back to the pitch that you used to have. You aren't going to ruin or damage your newly-improved engine over another season with that pitch. Most sailors have probably never even run their engine at 3,000 rpm anyway!
4. If you decide that you really would rather run next season with the prop at the current pitch, just get used to the control issues. I suspect that you can deal with it even if it is a bit awkward in difficult conditions. You haven't described any more difficulty than most of us deal with routinely for various and sundry reasons, I think.
5. It won't hurt to use the 2-blade fixed prop if that is what you want to try. It's worked fine for thousands, if not millions of sailors. It will work for you, too. If you really have to scratch an itch ... re-condition it. It's only money and you'll find out if it was a waste or not. It's not a big deal, either way. When you are sailing, it's not like you are going to be thinking about the performance of your re-conditioned prop!
6. Do some research and shopping for the new prop that will make you happy. Get advise from the prop companies. Get advise from the engine mechanics. Shop for pricing. The winter after next, buy your new prop after you have a fine running engine and you are ready to splurge.