CD28 / Volvo MD7A propeller sizing

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Phillipgh
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Joined: Apr 9th, '19, 14:50

CD28 / Volvo MD7A propeller sizing

Post by Phillipgh »

Hello all,

I’m looking to upgrade my propeller to get some more speed and performance out of it. I find the small two blades prop I currently have makes maneuvering into a slip difficult. Has anyone put a larger prop on a MD7A? Trying to find out what people are currently using that has worked well. Thank you.
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S/V Ethan Grey
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Re: CD28 / Volvo MD7A propeller sizing

Post by S/V Ethan Grey »

Hi Phillip,
From what I can tell, the prop for an MD7A on the CD30 is between a 12LH9 2 blade on the small side to a 13LH12 3 blade on the larger size. I would think it would be the same for the CD28. This is based off of my searching the archive for those that either had a prop replaced or had the original prop on the boat. Take it with a grain of salt, because I couldn’t find a clear, definitive answer. I believe many prop manufacturers will be able to size it for you based on displacement, horsepower, max RPM, etc.

I believe the 3-blade is best for thrust and maneuverability at the risk of increased drag, while the 2-blade has less drag but you give up on thrust. I am thinking of going with a 3-blade on mine, but I’m still undecided. I currently have a 15” 2-blade max-prop and it is oversized for the rudder aperture.

Keep us posted on what you decide.
-david
David
S/V Ethan Grey
1981 CD 30C, Hull #199
Niceville, FL
CDSOA# 1947
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mgphl52
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Re: CD28 / Volvo MD7A propeller sizing

Post by mgphl52 »

When I repurchased KAYLA, the first thing I did was put a Campbell Sailor prop on her. I went from 3-blade Michigan wheel to the 3-blade sailor. When we raced with the Michigan wheel, I always left her in neutral and on a good day you hear her churning! The drag on the sailor is so low that it doesn't matter so I shift to full-reverse to get the lever out of the way.
-michael & Toni CDSOA #789
s/v KAYLA CD28 #318
2012 FLSTC Heritage Classic
Niceville FL
+30° 30' 24.60", -86° 26' 32.10"
"Just because it worked, doesn't mean it works." -me
No shirt + No shorts = No problem!
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Jerry Hammernik
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Re: CD28 / Volvo MD7A propeller sizing

Post by Jerry Hammernik »

I also switched to a Campbell Sailor prop. I don't notice any issues with drag (I'm not a racer) and I picked up a knot under power at the same rpm.
Jerry Hammernik

"Money can't buy happiness, but it sure can buy a lot of things that will make me happy."
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S/V Ethan Grey
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Re: CD28 / Volvo MD7A propeller sizing

Post by S/V Ethan Grey »

Do you guys know what size your prop was?
David
S/V Ethan Grey
1981 CD 30C, Hull #199
Niceville, FL
CDSOA# 1947
Phillipgh
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Re: CD28 / Volvo MD7A propeller sizing

Post by Phillipgh »

Thanks for the information. The data on the sizes for the CD30 are helpful. The Campbell sailor looking interesting. Do you guys remember what size prop you used?
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S/V Ethan Grey
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Location: S/V Ethan Grey - CD 30C

Re: CD28 / Volvo MD7A propeller sizing

Post by S/V Ethan Grey »

I just sent a request for propeller size to westbynorth.com for a 3-blade Campbell sailer for the MD7A. I’ll post as soon as I get a reply.
David
S/V Ethan Grey
1981 CD 30C, Hull #199
Niceville, FL
CDSOA# 1947
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mgphl52
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Re: CD28 / Volvo MD7A propeller sizing

Post by mgphl52 »

S/V Ethan Grey wrote:I just sent a request for propeller size to westbynorth.com for a 3-blade Campbell sailer for the MD7A. I’ll post as soon as I get a reply.
I just sent them a message asking if they had a record of the prop I bought for KAYLA in 2016...
Surely I filed the info somewhere but I haven't a clue as to where... :(
-michael & Toni CDSOA #789
s/v KAYLA CD28 #318
2012 FLSTC Heritage Classic
Niceville FL
+30° 30' 24.60", -86° 26' 32.10"
"Just because it worked, doesn't mean it works." -me
No shirt + No shorts = No problem!
Phillipgh
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Joined: Apr 9th, '19, 14:50

Re: CD28 / Volvo MD7A propeller sizing

Post by Phillipgh »

Campbell got back to me. Looks like for the MD7A the size is 13x8 for three blade. Price is 665 plus shipping. That’s a pretty penny for a propeller. What do you guys think? Is the Campbell really worth it?
Phillipgh
Posts: 9
Joined: Apr 9th, '19, 14:50

Re: CD28 / Volvo MD7A propeller sizing

Post by Phillipgh »

Campbell got back to me. Looks like for the MD7A the size is 13x8 for three blade. Price is 665 plus shipping. That’s a pretty penny for a propeller. What do you guys think? Is the Campbell really worth it?
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S/V Ethan Grey
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Re: CD28 / Volvo MD7A propeller sizing

Post by S/V Ethan Grey »

I just got the same response. They must be wondering why all of these Cape Dory guys are asking all at the same time ;)

Yeah, I’m on the fence with this one. I’ve heard great things about the Campbell, but I have to ask myself is it really worth the extra $$$. I’m not really a racer, but getting more performance is always a good thing.

Now that I know that Kayla has one, I might just find a buddy with some SCUBA gear :)
David
S/V Ethan Grey
1981 CD 30C, Hull #199
Niceville, FL
CDSOA# 1947
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mgphl52
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Re: CD28 / Volvo MD7A propeller sizing

Post by mgphl52 »

S/V Ethan Grey wrote:I just got the same response. They must be wondering why all of these Cape Dory guys are asking all at the same time ;)

Yeah, I’m on the fence with this one. I’ve heard great things about the Campbell, but I have to ask myself is it really worth the extra $$$. I’m not really a racer, but getting more performance is always a good thing.

Now that I know that Kayla has one, I might just find a buddy with some SCUBA gear :)
Well... sheeeet! At least have him put *some* prop back on and clean the hull while he's there...
-michael & Toni CDSOA #789
s/v KAYLA CD28 #318
2012 FLSTC Heritage Classic
Niceville FL
+30° 30' 24.60", -86° 26' 32.10"
"Just because it worked, doesn't mean it works." -me
No shirt + No shorts = No problem!
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S/V Ethan Grey
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Location: S/V Ethan Grey - CD 30C

Re: CD28 / Volvo MD7A propeller sizing

Post by S/V Ethan Grey »

Well, today I pulled the trigger and ordered the new Campbell Sailer, 13LH8.5, they are left hand props, correct? I’ll let you know how it goes once I get it in and installed.
David
S/V Ethan Grey
1981 CD 30C, Hull #199
Niceville, FL
CDSOA# 1947
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mgphl52
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Re: CD28 / Volvo MD7A propeller sizing

Post by mgphl52 »

S/V Ethan Grey wrote:Well, today I pulled the trigger and ordered the new Campbell Sailer, 13LH8.5, they are left hand props, correct? I’ll let you know how it goes once I get it in and installed.
Whew! Now I can quick worrying... :D :D :D
-michael & Toni CDSOA #789
s/v KAYLA CD28 #318
2012 FLSTC Heritage Classic
Niceville FL
+30° 30' 24.60", -86° 26' 32.10"
"Just because it worked, doesn't mean it works." -me
No shirt + No shorts = No problem!
Phillipgh
Posts: 9
Joined: Apr 9th, '19, 14:50

Re: CD28 / Volvo MD7A propeller sizing

Post by Phillipgh »

Found a second hand 13x12 LH Michigan sailor prop for a steal on eBay. I know Campbell sailer suggested 13x8 but I could t find any with that low of a pitch second hand. I’m a little worried about the higher pitch in relation to its long term effect on the transmission. Anyone have any insight to if running a higher pitch would cause issues?
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