SD20 prop

[Patcheloupe]

On the very end of a passage from RI to PR, we lost our prop (thought we lost the transmission and then discovered that the prop is gone...).
I have been researching this and came up with a few questions that I just can't figure out:
1. I have a catamaran with twin engines. Does the SD20 always rotate in the same rotation? Meaning, by definition do I need two LH props?

2. I found that I should use Volvo props. Volvo also has their own Cone nut, which is much less expensive than Yanmar. Would that fit?

3. I have been desperately trying to understand the "Spacer" that goes in before the prop. If I am using a Volvo prop, and a Volvo cone, is there an equivalent Volvo part that will replace this Spacer? I am in PR and trying to save overnighting from several different providers.

4. Any other prop types (fixed blade) that will fit SD20 without modifications?

Any inputs deeply appreciated!

[DotDun]

Originally Posted by Patcheloupe

On the very end of a passage from RI to PR, we lost our prop (thought we lost the transmission and then discovered that the prop is gone...).
I have been researching this and came up with a few questions that I just can't figure out:
1. I have a catamaran with twin engines. Does the SD20 always rotate in the same rotation? Meaning, by definition do I need two LH props?

2. I found that I should use Volvo props. Volvo also has their own Cone nut, which is much less expensive than Yanmar. Would that fit?

3. I have been desperately trying to understand the "Spacer" that goes in before the prop. If I am using a Volvo prop, and a Volvo cone, is there an equivalent Volvo part that will replace this Spacer? I am in PR and trying to save overnighting from several different providers.

4. Any other prop types (fixed blade) that will fit SD20 without modifications?

Any inputs deeply appreciated!

The "spacer" in front of the prop is a Yanmar part, use Yanmar only. Don't take a chance with anything else.

As you've figured out, Yanmar doesn't make props. Volvo is a good choice for a fixed blade prop, the 2 blade fixed is Volvo part # 850342 for a 16" x 11.

I can't answer if Volvo prop nut will work, I'm using the SeaHawk locking nut system. I found Yanmar's prop nut solution to be inferior due to no positive locking system.

[Patcheloupe]

Thanks!
Do you remember where you got the Seahawk nut? Was it in the US?
Do you know if the SD20 always rotates in the same direction? This is interesting because it means that the props are NOT counter rotating by design (twin engines)

[DotDun]

Originally Posted by Patcheloupe

Thanks!
Do you remember where you got the Seahawk nut? Was it in the US?
Do you know if the SD20 always rotates in the same direction? This is interesting because it means that the props are NOT counter rotating by design (twin engines)

The Seahawk nut is from Frank and Jimmie's Prop in Ft. Lauderdale, their part number MP14 - "SeaHawk Locking Nut System for Yanmar Saildrive Prop for SD20 Saildrive"
Home: Frank & Jimmie's Propeller

AFAICT, rotation on the SD20 is a choice of the installer when connecting the shift control linkage. You simply run one in reverse, the gear ratio is the same (2.64:1) for both forward and reverse.

My props rotate the same direction. With 2 blade fixed, I've never noticed any prop walk.

[hugosalt]

Have original Volvo prop that I removed from my SD20 saildrive
when I fitted folding prop...should be able to find it with cone
and bolt if will help you. Was original equipement on saildrive when boat new.
Volvo prop #850341-9 14x9 2 blade L.H. Not new
by any means but if size good may get you going until you can
replace with proper new. No cost to you, just shipping.

[Patcheloupe]

That's great! PM sent. Thanks!

[svstrider]

Originally Posted by Patcheloupe

Thanks!
Do you remember where you got the Seahawk nut? Was it in the US?
Do you know if the SD20 always rotates in the same direction? This is interesting because it means that the props are NOT counter rotating by design (twin engines)

I have 2 SD20's on cat. Left hand rotation both. Kiwi props.