Propeller size and pitch

[Bev & Billy on Sta-sea-dawn]

What size and pitch prop came on the W40 on the 365 ketch hull originally.  I do not know where my prop came from that is on hull 193.   I think it is a 17 in 12 pitch right hand.  Standing behind the boat, the prop turns clockwise.  The motor, standing at the helm looking at the front of the engine turns counter clockwise.
I am going to take the prop off Friday, but I had it off once before and I think it is labeled 17/12 LH.
Can that be possible.  But looking at the prop in the water from the back of the boat it turns clockwise.

[Jim S]

Phantom, then Dixie Girl, hull 341 was commissioned in 1981 with a 17x10LHP.  My eternal appreciation to the original owner Arthur Reuter for preserving all materials related to the commissioning and rating.

[Bev & Billy on Sta-sea-dawn]

Jim.
I do not know why I am so confused about this prop thing...LH?RH.
My engine turns to the right out of the transmission headed to the V drive.  then to the left leaving the V drive so out side of my vessel in the water, the turn is clock wise or to the right....I have a 17/12 that is labeled LH.  No one else on the club has responded but last year I thought some one told me theirs was a RH???

[Bev & Billy on Sta-sea-dawn]

I must be dumber than dumb.....I just do not understand.....

Ok....I found these two definitions on the web....but I also found a picture of a left hand prop on Ebay....it appears to be the opposite of the one on my W40.  My shaft turns clockwise.  My prop is labeled LH.  But it looks like the blade is cutting water and pushing in backwards turning right.....?

Can a prop be LH and be on the shaft that turns clockwise?

I found these definitions on the web......................1..2...

1. Most single engines use a standard rotation. Most twin engines use one of each. To determine what rotation you have, look at your prop as if on a boat. Position a blade pointing straight up. If the right-hand side of the blade is closer to the hull than to you, it's a standard rotation.


2. the way you can tell is from the tip of the blade which way would you slide down? if you would slide to the left it's a left hand if you slide to the right it's a right hand...works either way you look at the blade...

[Jim S]

Looking from behind the propeller, if the propeller turns clockwise to move the boat forward, it is a right handed propeller.  Most 365s came with the Westerbeke 4-108 (107) which used the LHP.  I have the Westerbeke 35dThree which needs a RHP.  The basic offset construction of the shaft/stern tube was to counteract the sideway slip caused by the LHP as well as allowing removal of the shaft. 

Propellers are stamped on their collar rims with the diameter, pitch and rotation.  One would assume the markings are correct. 

The fact that you have a 17x12 propeller probably indicates you do not have the Westerbeke 4-108 and could easily employ a RHP propeller. 

Of course, you may have a bastard size propeller on and are running it backwards to go forward.....stranger things have occurred.  Do you have a very powerful reverse?

[Jim Cozy]

All of the other stuff aside, the standard W-40, Walter V-drive in the 365 is a Left hand prop. This means that viewed from behind, the prop turns counter-clockwise when in forward. Thus, she walks to starboard in reverse. If the prop is labeled "L" it is definitely a left handed prop and appropriate for the ORIGINAL Pearson setup. Jim

[INCOMMUNICADO]

If anybody would like to know.I was looking through the Pearson Yacht parts Catalog date 6-1-80 and they have the prop listed as 3 blade,17x10x1 1/8  $231.87. Allen

[PeteW]

Time for a sanity check.

All these Westerbeke diesel engines and most normal automobile engines for that matter turn CW when viewed from the front (pulley) of the engine.  Because of the gears in the V-drive, direction from input shaft  to output shaft is reversed. So its CW in and CCW out. Because the front of the motor faces aft, the propeller will spin CCW when viewed from the back of the boat looking forward. In that direction you are still looking at the front of the motor and not the flywheel.

Looking at a prop from either side, if the leading forward edge is on the left, its a left hand prop. To move forward in the water its easy to see that it must turn CCW. And vise versa.

Tip: If you can hold the prop in your left hand without a blade interfering with your thumb, its a left hand prop. A Right hand prop will only fit comfortably in your right hand.

The 71C direct drive gearbox and the Paragon does not change the direction of rotation. But a Hurth gearbox found on the Yanmar engines does, making the prop rotation CW  (right hand)  It also adds another 2:1 gear reduction (2x2 =4:1 overall) resulting in a bad situation for prop selection.

I hope this helps.    Pete

[Bev & Billy on Sta-sea-dawn]

Ok................so far this is what I know and do not know.....
I have the prop off the boat and compared to a RH in the ships store....it appears to be RH...but with no raking....straight in the middle, forward and back are all most identical.  The hub only has these markings.

6 03 Michigan MP P/N 40 48 74....what in the world does that mean?  I have an email in to the Michigan web site.......It looks like it is 17 wide...the pitch is ?...by definition on the MP web site it says the blade is not raked.  Can anyone help with the other numbers?

I finally figured out that when the prop was on the indent (forward)...my boat backed up and vis-versa.  So, I hope that when I put on a 17/10 LH it will reverse that and be going forward when the indent is engaged.