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.
CD28 / Volvo MD7A propeller sizing
Moderator: bobdugan
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S/V Ethan Grey
- Posts: 166
- Joined: Apr 19th, '19, 06:52
- Location: S/V Ethan Grey - CD 30C
Re: CD28 / Volvo MD7A propeller sizing
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
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
S/V Ethan Grey
1981 CD 30C, Hull #199
Niceville, FL
CDSOA# 1947
Re: CD28 / Volvo MD7A propeller sizing
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!
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
- Posts: 258
- Joined: Feb 5th, '05, 15:02
- Location: Lion's Paw CD 28 #341
Lake Michigan
Re: CD28 / Volvo MD7A propeller sizing
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."
"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
- Posts: 166
- Joined: Apr 19th, '19, 06:52
- Location: S/V Ethan Grey - CD 30C
Re: CD28 / Volvo MD7A propeller sizing
Do you guys know what size your prop was?
David
S/V Ethan Grey
1981 CD 30C, Hull #199
Niceville, FL
CDSOA# 1947
S/V Ethan Grey
1981 CD 30C, Hull #199
Niceville, FL
CDSOA# 1947
Re: CD28 / Volvo MD7A propeller sizing
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
- Posts: 166
- Joined: Apr 19th, '19, 06:52
- Location: S/V Ethan Grey - CD 30C
Re: CD28 / Volvo MD7A propeller sizing
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
S/V Ethan Grey
1981 CD 30C, Hull #199
Niceville, FL
CDSOA# 1947
Re: CD28 / Volvo MD7A propeller sizing
I just sent them a message asking if they had a record of the prop I bought for KAYLA in 2016...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.
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!
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!
Re: CD28 / Volvo MD7A propeller sizing
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?
Re: CD28 / Volvo MD7A propeller sizing
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
- Posts: 166
- Joined: Apr 19th, '19, 06:52
- Location: S/V Ethan Grey - CD 30C
Re: CD28 / Volvo MD7A propeller sizing
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 $$$. I’m not really a racer, but getting more performance is always a good thing.
Now that I know that Kayla has one, I might just find a buddy with some SCUBA gear
Yeah, I’m on the fence with this one. I’ve heard great things about the Campbell, but I have to ask myself is it really worth the extra $$$. 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
S/V Ethan Grey
1981 CD 30C, Hull #199
Niceville, FL
CDSOA# 1947
Re: CD28 / Volvo MD7A propeller sizing
Well... sheeeet! At least have him put *some* prop back on and clean the hull while he's there...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
-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!
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!
-
S/V Ethan Grey
- Posts: 166
- Joined: Apr 19th, '19, 06:52
- Location: S/V Ethan Grey - CD 30C
Re: CD28 / Volvo MD7A propeller sizing
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
S/V Ethan Grey
1981 CD 30C, Hull #199
Niceville, FL
CDSOA# 1947
Re: CD28 / Volvo MD7A propeller sizing
Whew! Now I can quick worrying...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.
-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!
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!
Re: CD28 / Volvo MD7A propeller sizing
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?