volvo penta propeller...

[vince59]

I have a bunch of propellers and I am looking for having a good set for my boat however I can't get the equivalence between the propellers because I only have the A6, or B6 and so on...is there a kind of comparison chart were tolook to get the pitch and diametre value for each volvo penta type propeller?
I am looking to find the measurement for a B6 innner propeller three blades against a A6 and A7 same inner prop.
Thank you

 

[Scott Danforth]

Re: volvo penta propeller...

the B and C series are the same (B being aluminum, and C being Stainless). The A line is for diesels with the inner prop being 4-blade and the pitches are different. there is no diameter/pitch chart comparisons that I know of.

 

[Maclin]

Re: volvo penta propeller...

Scott has summed it up, not much more detailed info that I have been able to find.

I can only add that a DuoProp B5 with 1.95 ratio gives performance numbers in my boat as if it was a 22-23 pitch or so. Each step (from B5 to B6 for example) seems to be 1.5-2 inches pitch, realize this is total approximation on my part.

I am trying to attach a Volvo Prop guide, let's see how it goes....

 

[Maclin]

Re: volvo penta propeller...

Scott, the 4blade A series is the rear prop, just clarifying that as I was not sure exactly what you meant by inner prop.

 

[vince59]

Re: volvo penta propeller...

the four blades is the outer the three blades is the inner, I am talking for a diesel engine with a290dp sterndrive. I am curios about pitch and diameter of the A7 propeller kit. Currently I have an inner A7 (three blades) and outer A6 (four blades)...engines (two AQDA41A 200HP) run up to 3900 rpm with little bit over 35 knots. Unfortunately the inner propellers are very old and must be replaced.

 

[Scott Danforth]

Re: volvo penta propeller...

NEVER NEVER NEVER mix volvo props. always use both an A7 inner/outer or a6 inner/outer never run an A7/A6 combo

 

[vince59]

Re: volvo penta propeller...

I am aware about your warning, but this is what I found installed on the boat (inner A7 and outer A6) and I am not very sure if I should leave the situation the way it is, I would definitely respect the rule and have both A7 installed. I do have A7 outer available and I am going to buy 2 new A7 inner. Let me ask a question for my better undertsanding...what could be the actual damage when using such a combination of propeller (inner A7 and outer A6)? We tested the boat it runs ok with WOT ok (3800rpm) and good speed.
Unfortunately I do not know how long that combinatin has been used as the former owner has passed away time ago. Thank you for your reply.

 

[Maclin]

Re: volvo penta propeller...

I think Volvo has good engineers and spent a lot of money on the research so I tend to not second guess what they did on the DuoProps. There is a lot of tech and fine details they worked out on how the different diameter props work with each other. I think cavitation could be one result of mis-matching. Vibrations at certain rpms, things like that.

 

[vince59]

Re: volvo penta propeller...

I agree with you, it is just a tech question I was wondering. I have no clue how long this mixed combination has been used. Still I believe you must keep the same propeller size.