Are all Pearson design 323 shafts/strut off to starboard ?

[The Great Godsea]

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.

[selene]

<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.

[Rusty Pelican]

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

[Sea Haven]

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!



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!!


 

[Eibeltje]

"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.

[Dolce_Vita]

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.

[selene]

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.

[Sea Haven]

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

[Alma]

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.

[Weatherhelm]

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


 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

[Alma]

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.