ANY MARKING on Volvo Penta duo props indicating port / starboard ?

alan ber

Petty Officer 2nd Class
Joined
Jun 29, 2008
Messages
143
I had my F 4 's re- pitched too F 2's . Corrected my problem
Asking shop , is there a difference in port / starboard ? He said NO they are the same only go on one way ?
I installed
Boaters swear by twin screw ? They say they dock never using wheel only engines ?
Twin screw is new too me . After 3 years still not comfortable reversing into dock
Boating 40 years single screw ,
comfortable docking one engine which is what I presently do, coming into staging area at my marina on starboard which is the engine with PS . .
Makes me crazy that for what ever reason I cant get comfortable and handle twin screw as easy as I do single

Going thru Regal repair book , I came across section on docking & props
It indicated mark props , don't mix them ?
Questing why I have such issues at dock , DID I MIX PROPS .
IS there any markings some place on props , starboard , port , same with the smaller props ?? What does the smaller prop do .
thanks


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Thalasso

Commander
Joined
Jan 18, 2011
Messages
2,876
Doesn't matter. Mixing props refers to using say stainless with aluminum.
If you look at the prop shaft you will see you cant even put them on wrong. The inner prop will have a larger bore

If you notice on the props the pitch goes the opposite way compared to the other. What it does is help to cut down on cavitation
Don't buy into the myth of prop timing either. No matter the position you put the props on at some point the blades will pass over the other.
Large prop on first. Small prop on next. Go boating
 

alldodge

Moderator
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Mar 8, 2009
Messages
40,582
If you have one prop on each drive, then yes the props get marked because one is LH and one is RH. Duoprop are counter rotating on each drive, so one LH and one RH prop on each drive.

The duoprop or Merc B3 can back up without walking to one side because they rotate in opposite directions. This opposite rotation opposes the walking sideways of each prop.

Twin screw boats are easier to park and you will get adjusted to it with practice. Go to a place where your not real close to things and practice. Take a weight or small anchor and tie some kind of float to it, then try backing around it usin only the drives. Make sure the drives are facing straight forward
 

tpenfield

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Jul 18, 2011
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As the others have said, there is no way to mix the props on a counter rotating twin prop drive, because the prop sets are the same.

One side in forward, the other side in reverse makes the boat spin around its center (pretty much), which helps for close docking maneuvers.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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you only have to deal with mixing props with single prop drives. in that case, one is RH one is LH

on twin DP drives, same props on both outdrives
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,286
What the above have written is spot on, but worth noting that in most, of not all DP cases, single or twin set up....the boat will turn better to port. The larger inner prop (on the drives I had at least) with RH rotation always has a say in that, over the smaller LH outer prop.
 
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