E32 Prop size and engine mounts
Date: November 20, 1998
From: Paul Uhl endvr32@endeavourowners.com
Hello everyone,
My boat yard recently told me that the 2 blade prop (16x12RH) that we have on our E32, which came with the boat and is the size specified by Endeavour, is too large. They claim this because the clearance between the prop and boat is roughly 1/2" and should be at least 1" or more. It seems I've recently read something to support this but I was wondering what other E32 owners 1) prop size/type was, and 2) what your clearance is, and 3) if you've noticed any problems.
The only reason this came up was that I mentioned to them that at about 1,000 to 1,300 RPMs, we get some harmonic vibration. Given that we have a 3-cylinder Yanmar which would have some harmonics, it didn't concern me, especially since it's fine at other RPMs. Also, if vibration was an issue, I would think that some cracking of the fiberglass where the prop strut exits the boat, or damage to the cutlass bearing would be apparent.
The other thing that concerns me is that it's about time to replace the motor mounts and if there is enough 'sag' in them, new ones may raise the engine enough to pivot the prop slightly away from the bottom of the boat and increase the clearance.
Any thoughts?
Lastly, does any one have a PSS dripless 'stuffing' box? If so, do you have any comments good or bad?
Date: November 21, 1998
From: Ron Brown ronbrown@moneymailer.com
Paul,
My 79 E32 came with a the same two bladed prop you have and was changed to a three blade by the previous owner. He was an engineer type and researched every decision carefully. For power I like the this prop, and it seems to match the motor well. Drag under sail is noticable. Interesting, I have discovered that if I allow the prop to free wheel under sail that the boat preforms better. Thats not what the books say, and its not suppose to be good for the transmission but it works for me. You can contact the Yanmar factory techs and recieve valuable input about matching props to motors. We have always found them to be most helpful.
Date: November 21, 1998
From: Tim Cropley TimWana@aol.com
I have no insight on the engine and prop questions , But as for the pss seal their great , i replaced mine with one last winter .....no prob in application and easy to install ........
Date: November 24, 1998
From: Jim McMordie jim_mcmordie@gilbarco.com
Interesting ... I was going to have the local diver change my prop to a 16" 2-blade based of past conversations with you about my boat pulling to port. Now it looks like you're questioning your set-up. I suppose "if it works ... use it". I think I'm still gonna try your set-up.
My current set-up in a 14" 3-blade prop. I have about 1-1/2" clearance. Just what you'd expect.
Cutlass Bearing supports - When I first got my boat there was a vibration that was causing the cutlass bearing to wear out about once a year. When we got the boat on the lift, we found the shaft was just barely bent; about 1/8" total run-out. The only way to see it was to put a scale against the bottom of the boat (to stabilize it) line it up to the prop shaft and turn the shaft. Just looking at the shaft without something propped against the hull as reference, you couldn't see the bend. We also noticed a very small movement of the cutlass support inside the hull. The crack around the support would widen and narrow just a little when you wiggled it. I was new at this. The mechanic said the cutlass support typically is bolted to the hull and glassed over. He started removing glass to get to where the support would be bolted. We never found those bolts. We ended up cutting the entire cutlass support out of the hull. The hull is about 7" thick around that support. The bronze support had no bolts. Instead, the support had the upper part sawed off, then the thing was just stuck into the hull and glassed in place. The mechanic said he'd never seen such a thing.
We had a local machine shop make a new support (cut, form, & weld) from stainless. This new support is now bolted to the bottom of my boat. and I no longer have problems. As you might guess, this whole process (plus a new stainless prop shaft) was very expensive. It'll be interesting to see if anyone else has been thru this.
Date: November 28, 1998
From: Robert G. Chamberlain rchamber@snip.net
Paul,
Finally got to boat to check on my prop. I also have a 16 X12 and perhaps 3/4's of an inch clearance. I have had no problem with this setup. I have a two cylinder Yanmar (2QM20H).
I would be concerned about changing the angle on the prop shaft. I don't believe that the cutless bearing will move with the new angle. Also it is my understanding that the reason the Endeavour backs up so badly is the downward angle of the prop shaft. Increasing this angle might make it worse.
I don't have the PSS arrangement. I have standard stuffing box.
Date: December 1, 1998
From: Paul Uhl endvr32@endeavourowners.com
I was on my boat this past weekend and checked the clearance on my prop and found it to be a tight 1/4". It wasn't that I was intending to 'change the angle' so much as I was woundering if old, wornout engine mounts may have done so over time. If that was the case, the shaft would be out of alignment now and replacing the mounts might bring it back into alignment, lowering the prop. Alas, my mechanic guru said it ain't so. Maybe a feathering prop for Chistmas?
Date: January 12, 1999
From: Robert G. Chamberlain rchamber@snip.net
Paul,
Have some bad news that I ran across as an excerpt from the "Propeller Handbook". It stated that the minimum clearance of the propeller tip to the bottom of boat should be .15 to .20 times diameter of the prop. My E32 is no where close to that. With a 16 inch prop that works out to be 2.4 inches (at .15).
Date: January 14, 1999
From: Kevin D. Coon kkcoon@viaccess.net
Greetings!
On prop clearance, the suggested clearance probably has more to do with maximum thrust than anything else. I've used 14" , 15", and 16" props on my 32 and the 16" is by far the best.
Date: January 14, 1999
From: Carl Hibbard Chgypsy@aol.com
The statement is very correct with the prop at right angles to the hull. It creates a negative pressure area which can in fact cause the fiberglass to delaminate or possibly get torn away. Looking at the standard prop, with the angle it sits at you don't have that much cavitation.
Date: January 18, 1999 More of my bottom paint is worn away in the area immediately above the prop than anywhere else. Mine is the standard two blade 16 inch diam. It seems that most designers call for a prop tip-hull clearance of ten percent of the blade diam.("The Complete Book of Boating") by Ernest Zadig,(Prentice Hall). In the case of the E32 this would be 1.6 inches, but my E32 has about one half inch. So it would appear that a fourteen inch diam. would be the right one, but in a two blade this would give much less thrust (drive) . Okay, how about a three blade fourteen incher . Well, a fixed three would really be a drag under sail, though I would recommend it for traveling the ICW, yet a feathering (MaxProp) three blade would be the correct answer ( at a 1999 cost of $2,000.00). So for now,I will retain the two blade sixteen inch and double coat the bottom above it.
Date: January 20, 1999 Paul, Thanks
Date: March 13, 1999 I have a 1970 Irwin 32 (same as Endeavour). The old 2 bladed prop pulled the boat to port under power. Last year I repaired with a koboto 28hp which required me to change to a right hand prop. The vibration and the pull to port were eliminated with a smaller prop which increased the clearance between the prop tip and the boat. runs fine now with a 13-13 prop
Date: March 18, 1999 My E32 motors at around 5.8k at about 2800 rpm; 24 hp Yanmar. If I push it up to about 3000 I can get to around 6k (all this is off GPS). When I push the throttle up more, it seems like the boat actually slows down. Certainly doesn't go faster. The bow of the boat starts trying to climb the bow wake and we just waist energy ... ain't gonna happen. I still havent tried the 16" two-blade prop set-up yet but I still plan to. Who the heck has time to even get to the boat any more!!
Date: June 4, 1999 I am wondering if anyone with an E33 has a three blade prop, and if so, what the dimensions and pitch might be. Also, pros and cons.
Date: June 8, 1999 Hey Skipper, For the 3 blade prop, per my owners manual, they suggest a 16x12x1" RH and for a 2 blade prop a 15x15x1" RH. If you currently have a 2 blade and it is as specified then I would go with the 16x12. If you think you need more power, be careful. Sometimes the mixing elbow will become 'loaded up' with carbon and this will cause a greatly noticed decrease in power. A prop if sized to big will cause the engine to overheat and may not let the engine rev up to the idea operating range. And a prop to small will rev up to fast and cause cavitation, air bubbles around the prop and causing just as must harm. A good test is to start your engine at dock side, after the engine warms up, place in gear while tied to the dock. Now carefully rev up, taking the slack out of your dock lines. At this point you should be able to reach around 80% of your peak RPM range. If you do not, then your prop is to big but if you do then the prop is to small. I hope I have been of some help. And of course all of this is pending that you have the engine that is specified for this vessel, Yanmar Diesel 3GMF 2.61 ratio, fresh water cooled. At this point I am going to go, I am exhausted and thankful to be back on US soil. Just completed a trip to Cuba, and will write more later.
Date: September 30, 1999 Hi Folks... Black soot on the transom: this means unburnt fuel is being exhausted from your system. At the least it means too much propeller, either the diameter or the pitch in some combination.. It indicates your engine is being overworked; you're not getting optimum performance and thrust; and (as in MY case), if your engine is old, too small for an E32, then it could lead to catastrophic failure. I had an original 12hp Yanmar one banger, on its side. I had it rebuilt after simple failure and changed to a folding prop (for racing). I was given wrong advice from the prop manufacturer wrt size and pitch of the prop and the engine 'exploded' one year later. I now have a very nice 2 cylinder 20hp Yanmar, upright. All things with the engine are now good, but this was very expensive!!!! Don't let it happen to you. When changing props use a marina which has computer software to calculate prop diameter and pitch as well as the prop manufacturer. They need to work with each other to find the best solution for your case. Unfortunately, the E32 hull limits the optimal diameter and you must rely more on pitch to get optimal thrust. Sorry...no problems with my gelcoat. Mine is a 1976 E32 CB. She's classic looking and a great heavy weather boat. I've raced in gale force (30-40kts), and survived five hours in a tropical storm (Earl) in the Chesapeake Bay 4 Sept 1998 with following seas breaking OVER the boat and into the cockpit!
Date: September 30, 1999 As an FYI, Michigan Prop and Yanmar have web sites that will allow you to properly (LOL) size yours. The URL is:
Date: February 21, 2000 For what it's worth, the three-bladed prop on my E32 is a 16RH14, and there is about 1-1/4" clearance between the blades and the hull. I have no idea if this prop is among the options offered by Endeavour, but it seems to work. At about 2500 r.p.m., I get an average of 5.5 knots Yanmar, which seems fairly respectable to me. There is quite a bit of "kick" (typically to port) when operating in reverse--this I attribute to the significant angle of the propshaft to the hull, the resulting backwash on the hull, and the shape of the hull just forward of the prop.
Date: February 23, 2000 Jay, The short rudder and Endeavour's hull form doesn't help either.
Date: November 28, 2000 Hello, I haven't measured the prop yet but I don't believe it is over 12" diameter. Has any E33 owner had prop change experience? If I read correctly, I should be able to do around 6 kts but she seems to be max'ed out at around 5.2 kts @ 2400 RPM.
Date: December 2, 2000 Carol and Bruce, As an FYI we typically run our engine at 2000rpm and cruise at about 4-4.5knts in calm conditions; +5knts @2500rpm. Also, I think the rule of thumb is that the MINIMUM clearance should be 15% of the props diameter. That would make the clearance for a 16" prop about 2.4" This is needed to reduce cavitation and vibration. In my case, our fixed 2-blade 16" prop only has 1/2" tip clearance which is not good. At some point I plan to invest in a feathering prop and reduce the diameter of the prop, in my case from 16" to 15", and at the same time increase the surface area of the blades to compensate for the smaller diameter. Last time I checked it would cost me about $1,500
From: Jack Blake B82094@aol.com
From: Randy Pickelmann (DUET) rwp48@aol.com
My 1980 E32 has a 24HP Universal diesel spinning a three blade prop. I'm unsure of the size, but my sense is that it is not pitched properly. When I run at what I believe to be cruising speed (2200 RPM) we make only 5kts. in smooth water...less in a headwind or chop. I feel that the boat should move at 6+ kts in smooth water. My plan is to have a mechanic check out my tach before I haul out this spring, but I'd like to hear what kind of speed other people are getting under power. This information may give me some insight before I re-prop the boat.
From: Craig NICH12345@aol.com
From: Jim McMordie Jim_McMordie@gilbarco.com
From: Steve Glick boatsri@cyberzone.net
From: Luther Carrier capcarrier@aol.com
From: Bob Flath oldthumper@istnet.net
From: Paul Uhl endvr32@endeavourowners.com
From: Jay Call jaycall@mediaone.net
From: Paul Uhl endvr32@endeavourowners.com
I'm not an expert but most of what you point out seems to be inline with what I've heard and read. The 3-blade prop will give you more walk than a 2-blade--especially when stopped as the prop works more like a paddle wheel, pulling you sideways until you generate enough backwards motion. Once you start going backwards, the rudder starts to work as the water flows across its' surface generating some lift.
From: Carol & Bruce lbm@amherst.com
I have had Cu Mara since late June and never really took note of the prop clearance discussed many in the forum. She just came out of the water on November 10th and where 32 owners are talking about 1-2.5" of clearance between the prop tip and the bottom-- I must have 5-6"!
From: Paul Uhl endvr32@endeavourowners.com
A 12" prop seems a bit small. Check the stamping on it as the standard size for an E32 or E33 is 16" x 12" or 15" x 15" prop. My 1982 has about 1/2" with a 16" x 12" prop. To determine the correct size beyond the spec list on our site, you can do an in water test. Basically you should be able to get your engine running at its max hp/rpm. For instance, our Yanmar 3GM is rated at 22.5@3600rpm. With the correct size prop I should be able to get the engine to run at 3600rpm, and also be able to reach hull speed--or very close to it--which is 6.8knts for the E32. If you can reach rpm but not hull speed you're under proped, if you can't reach rpm's but can reach hull speed then you're over proped.
