Pearson Yachts Forum
Pearson Boats - Common Systems => Engine and Drive Train => Topic started by: Eibeltje on November 16, 2013, 10:09:37 PM
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Are all Pearson 323 shaft or strut off to starboard ?
I ask. because nobody seems to have a steering problem only me.
We have a shaft off to starboard and with a left hand rotating prop our boat was steering strait,you could take your hands off the wheel and it won't very the course except for wind and current changes.Now we have a right handed prop and the boat pulls to starboard.
I like to hear from P323 owners with clockwise (RH) and anti clockwise propeller(LH) how there steering behavior is under engine power.
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Are all Pearson 323 shaft or strut off to starboard ?
I ask. because nobody seems to have a steering problem only me.
We have a shaft off to starboard and with a left hand rotating prop our boat was steering strait,you could take your hands off the wheel and it won't very the course except for wind and current changes.Now we have a right handed prop and the boat pulls to starboard.
I like to hear from P323 owners with clockwise (RH) and anti clockwise propeller(LH) how there steering behavior is under engine power.
As you can see from the attached image, our shaft is offset to port.
We have an Atomic-4 Gasoline engine. All atomic-4s use RH rotation.
We have no pull to either side, in forward, but TERRIBLE prop-walk to Port in reverse,
made worse by the fact that we have a 3-blade prop.
I believe all the diesel engines used on the P-323 use LH rotation, and
experience prop-walk to starboard when in reverse. I don't know about
their shaft offset, but I would assume it would be to starboard.
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I can't tell you where my shaft is offset, but I can tell you that I have a diesel, and a strong walk to stbd in reverse. The prop is left-handed.
I have no issues going forward - she tracks well under power and under sail (when the sails are balanced), with very slight weatherhelm.
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Thank you so much to take the time to respond to my nightmare .
Well,this is very new to me ! This explains why some boats don't have any problems with replacing there Atomic 4 engine with whatever is available because all transmissions for V drive are nowadays clockwise and your shaft is off to port.But you will run in big problems if you want to replace a Volvo transmission with the shaft off to starboard .I have not found any transmission- V-drive with LH rotation.I assume that SERENE has a Volvo MD 11 ,like ours. Have you found any transmissions which would support a LH prop rotation ?
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Selene has a Westerbeke 30B three cylinder 27hp engine, with a Hurth ZF V drive model ZF15MIV V-drive transmission.
The Westerbeke has clockwise rotation (when viewed from the front), like the Volvo (AFAIK).
Very mysterious. Are you sure the shaft is offset to Starboard? Could there be some other cause, something to do with rudder itself, or the steering setup? I only ask as it seems unlikely that Pearson would have changed the hull mould. What hull number are you (I am 212)?
How many blades do you have on the prop? As I understand it 2-blade props have worse propwalk than 3-blade.
I wonder...is the prop shaft offset moulded into the hull, or is is controlled by the seal, prop shaft strut and engine mountings?
I have heard that some people improve their propwalk by using the max-prop (and yet others disagree); also there is a propeller tuning company around here has a process whereby they cut the tips off the prop, and reattach the tips at right angles to their original position. They claim huge improvement of propwalk. Who knows if it works? http://www.rtkprop.com/
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Thank you "Selene" and " DULCE-VITA " .
If you look from the front of your boat you have a clockwise rotating prop.In my handbook that means you have a counterclockwise rotation if you look from behind the boat !That is what I understand the way to determine the RH/LH rotation .
Before we had a Volvo MD11 and this had a counterclockwise (LH) prop.I could take my hands off the wheel and won't very my course except for wind and current changes.
The marine service department manager advised us this new engine and transmission and with that the change to a clockwise rotating prop.In the sea trail the boat showed this pulling to starboard what is new for this boat.
Nothing was done to rudder or steering setup.
We are hull #68.
You think it seems unlikely that Pearson 323 would have changed the hull mold !We have proof with " Dulce-Vita " and our boat.
"Dolce-Vita " her shaft is offset to port !
We have the same boat with a shaft offset to starboard.(see attached picture)
And "Dulce-Via " has the right clockwise rotating prop as we have a wrong clockwise rotating prop .
I wonder that you have a ZF 15 MIV transmission what you only can use in clockwise rotation (seen from behind off the boat) under warranty.They don't support reverse position in forward.
Are you 100 % sure about your prop rotation ?
You could help me tremendous to find out which is your shaft offset (starboard or port)
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Wrong picture that is " Dulce-Vita " her butt.
Here is our Butt. See picture
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Unfortunately Selene is in the water all year round, and the visibility underwater is poor (2' on a good day) so it is not as easy to get a clear look at the offset. Also I'm not planning to dive on her soon - just changed the zincs and cleaned the hull a couple of weeks ago! However, here are some photos. Unfortunately the image from the stern is off-center; it looks like a portside offset to me. However you can clearly see the prop rotates in the opposite direction to you.
Dolce Vita is hull #42, so if they did change the mould it was an early change.
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I've been thinking about this - and hopefully others will let us know how there boats are set up. We need more datapoints.
Hull 42 Port offset Atomic 4 RH prop
Hull 68 Stbd offset Diesel RH Prop
Hull 212 ?port offset? Diesel LH Prop
The real anomaly of your prop shaft being offset to starboard. Are you sure of that? It is also possible I am wrong - the photo is not good. I checked with an expert, and the engine offset is set into the mold, so that is very unlikely to have changed. Gasoline was standard, and diesel was an option, so possibly Pearson had different inserts for the mold, one for diesel, the other for gas. Or one of us got the offset wrong!
Regardless, I think that the offset could be a "red herring". You have replaced your Volvo with a new engine (what?), and as a result your prop changed from a LH to a RH. Now you have bad propwalk. Makes sense - the old engine, prop and offset worked together to minimise propwalk; with the new engine the entire rotation appears to have reversed. :-(
Hopefully somebody else will chip in with a new datapoint.
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I am 100 % sure that our prop is located starboard of our rudder.We had to pull the shaft to put a new one in and they hauled it out on starboard side of the rudder.
The service department manager looked at the specs of our boat and advised us to go with a Beta marine 25 hp with a ZF 15 MIV transmission.
That is what we have now.
Yes it is very interesting but not if you are the rabbit who has to pay the bill !
I appreciate your input and I hope that more captains will react to this topic because this will be very interesting for anybody with a Pearson 323 who has to change the engine/transmission.
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" SELENE " if I look good at your prop it looks to me that you have a left handed prop on that picture.
Look very good how the ears of your prop show in comparison to our prop or "DULCE-VITA ".
It is very hard to see but I can make out the difference with your prop.
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Hull 265. offset to starboard. volvo penta diesel. not sure if prop turns clockwise or not in forward. pulls to starboard in reverse thats for sure. always an adventure backing into the slip, especially with some wind across the bow.
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P323 #174 Volvo MDllC . Starboard offset with a LH prop.
You can not tell by the picture, but here is my "sling shot" haha
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I believe the whole concept of "having to change the hull mold" is wrong.
If you think about it, it would be impossible to mold the shaft log in place. You couldn't release the hull from the mold if you did it that way.
I believe the passage was bored into the hull after it was removed from the mold, and the tube glassed in place afterwards. This would allow them to bore it with the desired offset, depending on whether they were building a gasoline or diesel boat.
Here's another (mostly unrelated) piece of triva to consider: 1977 is the first model year for the P-323. The model year for boat begins in August of the previous calendar year. My boat, hull #42, is model year 1977, but was built in December of 1976. This means that they cranked out FOURTY-TWO BOATS in five months!! That's almost two boats per week!! They almost certainly had two molds to be able to sustain that rate!
Hull number 18 (Lark in the Clear) was built in September of 1976. Again, 18 boats in 8 weeks is a little more than 2 a week!
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Thank you ,thank you ,thank you.
We know now that there are Pearson 323 with shafts offset to starboard or port.
If you have a left handed rotating prop with a shaft off to starboard ('RUSTY PELICAN ","GREAT GODSEA " (?) what transmission do you have ? Do you encounter any pulling to starboard /port if you are under engine power in forward.
"SELENE, we have now a ZF 15 MIV like you.You have a LH rotation . ZF told us this transmission supports ONLY a RH rotation,
I am confused now !?!
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i havent noticed the boat pulling when motoring. no idea what kind of transmission i have, although the mechanic who did my tune up last spring said it may be slipping a little.. just setting me up for the kill.
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<Ed: Yes, you are probably right, as usual :-)>
Yeah, I am confused also. I guess I'll have to pull my wetsuit on and look at my offset.
I did look at engine specs, and the Weterbeke claims a counterclockwise rotation when viewed from flywheel side - RH prop on a standard transmission, so I guess LH on a V-drive. The Hurth documentation says the ratings were for right hand turning engines ("i.e. engines having counterclockwise rotating flywheels when viewing the flywheel end of the engine") - which seems to agree with what they told you. So it *seems* my Westerbeke and the Hurth are well matched.
Yanmar engines are also counterclockwise viewed from flywheel side, so they would work well also.
Both the Beta and the MD11 seem have *clockwise* rotations (I looked in their current datasheets - may be different in older engines). So how come sometimes their props are - like your old one - are LH also? Has the engine design changed? And they say the engines can be used with a Hurth transmission, which seems to like counterclockwise...so maybe a call to Hurth would clarify?
Regardless, as you have certainly worked out by now, changing a LH engine/drive combo to a RH engine/drive combo is a no-no in general, especially with an offset prop shaft.
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Ed, you are correct about how Pearson offset the strut. I know a surveyor who specializes in Pearsons. He told me the strut is standard, Pearson "beefed up" the strut area in the mold, set the offset by removing glass.
I get a little pull motoring ahead, no big deal. I walks to starboard in reverse. sometimes that's a good thing. To go straight backwards apply power to move the boat, go to neutral and steer. Piece of cake
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Shipmates,
What the heck, I'll chime in!
Sea Haven
1978
Hull 124
Universal Atomic 4
Reduction Gear/Coupling: Paragon with Walter V-Drive.
Prop: This is off my Survey Report: "Fixed 3 Bladed bronze by Michegan, 16LH8. Intact and sights true."
Now I know for a FACT it's a RH prop, just look at the photo!
(https://dl.dropboxusercontent.com/u/2887041/SH_prop.JPG)
Ed "Dolce Vita" speaks A4 truth lol!!
You spin that clockwise when looking FWD while off the stern and in a few minutes Sea Haven will be hard to swim back to!
Bad Surveyor aside, I'm 99% sure Sea Havens shaft is offset to STARBOARD. Which is opposite of Ed's Dolce Vita!
I have to finish decommissioning her this weekend so I can up that to 100% (or not!) lol
From a prop walk point of view in the boat designers mind I would think if you need shaft offset to remove it, put the offset to the side it would do good. As my stern would want to walk to starboard as I power forward, it SHOULD be somewhat countered by the thrust vector offset of a shaft angle to starboard like mine. Which would be a good thing! Like a constant bit of right rudder!
However, all things being equal I find I have to give her a slight right rudder under power to keep her true. So my offset thrust to stbd is having little effect on my prop walk, and the stern walks to stbd forcing me to make minor course corrections. But there could be other factors here I'm missing (too much rudder play?) that I need to determine as I learn more about my new to me boat. a LOT more to learn lol!!
"Sub' Ed
PS: I just stared at that photo for the umpteenth time. I need to have a closer look at the prop, and have the yard look at this too. Looking at the blade shape, I'm getting the nagging feeling that previous owner installed it 180 degrees out, aka bassackwards! I know he did most, if not all the work himself (as evidenced by the 5 gal bucket of house wiring and AC wire nuts I pulled out!) So I think if I'm right the trailing edge of the blade is being used as the leading edge and vice versa! That makes the suction back now the pressure face! How much lift does an airplane wing get if it could fly in reverse? I wouldn't get on that plane! lol This makes for very inefficient thrust in our case. Maybe that's why the surveyor thought it was LH??
FWIW, as I told Ed offline I can't get her above 2K rpm, I thought this might be a cylinder compression issue, which now seems to have resolved itself (No. 3 was 60, now 100 psi), so I suspect clogged exhaust. This would definitely add to it!
What an epiphany!!
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"SILENE "thank you for your info.
The attachment shows the shifting (arrow). Please, shift in forward gear and look if the lever went UP or DOWN.
This will be a valuable info . I will explain having your answer.
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I seem to recall reading somewhere that the offset angle of the prop shaft had little to do with countering any prop walk. It was there solely to allow for installing/removing the shaft from the outside of the boat without running into the skeg. Sea Haven's observations seem to bear this out.
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Edd, as I recall you are correct in that the offset is not to counter prop walk - as you said, the primary purpose is to ease removal of the shaft. That being said, having the offset and the prop both in the same direction will tend to exacerbate any propwalk.
Eibeltje - reverse pushes the arm down - counterclockwise. Forward rotated the gear shaft clockwise. Note that the arm attached to the shaft in my boat faces forwards, as in the photo, taken through the door under the sink - left to the bow, right to the stern.
I hope this helps..I have come down with a cold, and so decided not to go snorkeling today to verify the offset!! What a wimp, eh? But FWIW Selene was originally sold with a Volvo engine.
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I checked Sea Haven yesterday.
I was INCORRECT!
My A4 powered 323 Shaft is to PORT, not starboard as I thought. I remember now I it was Cockalada II, a diesel 323 I had looked at last January that has it to stbd. That was the one I reported as user NAUTILUS that had that BAD rust stain on the keel. FWIW, she is now owned by Jerry and Wendy and she summers in the same harbor as Sea Haven! Apparently the son of the owner of the Marina which maintains my mooring owns a 323 as well. It's my understanding he is in the process of restoring her. That means there will be no less than three 323'as in my harbor! Mt Sinai Mooring field is 1nm x 1/2nm. Hopefully I'll get them to reach out here.
Finally, I checked my prop, the blades ARE symmetrical, not swept to either side, so the photo is misleading. The cross section of my blade seems to indicate it it installed correctly with the concave side (suction back) facing aft!
Now to find what's robbing power from me!
"Sub" Ed
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ALMA is Atomic Four powered with a Walter Vee Drive. Her shaft is port of the rudder skeg.
She backs to port. I use the prop walk to my advantage when docking.
I can't imagine motoring a SABRE with their prop shaft exiting the hull way off center.
There's a Running Gear piece in November SAIL Magazine featuring a Pearson 323.
It describes removing the prop and shaft for maintenance.
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On "Barefoot" my Pearson 323 #149 the shaft is offset slightly to the port side. this has the original Atomic 4/ Walter v-drive. RH prop I think Ed has hit the nail on the head it seems the A4's were offset to port and the diesel offset to starboard. but then there are the boats that have had things changed around then who knows
(http://wolffy.smugmug.com/Boats/Barefoot/i-P4gK72x/0/M/IMGP2183-M.jpg)
Its sort of hard to see in this picture but its the only one I have of the prop
Cheers and stay warm
Ron Wolfgram
Saint Paul, MN
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After a grounding I had to remove my shaft strut. When I was removing it I found a shim or more accurately an "adapter". It is over an inch thick. At the time I thought it was intended to correct for tolerances in the casting of the struts. Now I believe the adapter is used to offset the strut to port or starboard to compensate for propeller rotation. I can't remember if the strut was completely symmetrical- Maybe it is, and the adapter determines offset.
That knowledge would've come in handy while straightening the strut in a 40 ton press. Instead I had to make a correction then return 100 miles to the boat to match... Tedious at best.
I don't think the offset angle is acute enough to affect the short stern tube. Boats could be manufactured in identical molds and the adapters used to match offset to engine rotation.
Make sense?
If so- The adapter would be simple to cast out of thickened epoxy. THen you could switch the shaft to the other side and solve your problem.
I hope so.