Duoprop exeperts please help!
 

To put it simple I am lost when it comes to volvo duoprops...I am running a c7 series setup and am only getting @3800rpm. There are quite a few props on ebay at this time but I don't know if any of these setups will improve or hinder my performence...someone please help! The ones on ebay are:

1) f5 series
2) b7 series
3) f7 series

Johnny: I need to recall some knowlege from my duoprop days. If I recall right, the letter part pertains to the type of drive you have and to the material of the props(s). A "C" would be a stainless prop set for the DP280. A "F" would be a stainless for the DP-S. The number part pertains to the pitch (I believe.)

Looks like you need a "C" propset (if that was the right one in the first place - what kind of a drive do you have?) And if you have the right letter, you need to go down in pitch to go up in RPMs. 3800 sounds pretty revolting though. I'd ask around what performance you should get with that prop. Maybe there are other issues.

Volvo prop letters, decoded:

A: Aluminium, propellers for DP280, 290. Not for KAD42-44.

B: Aluminium propellers for DP280, 290

C: Stainless steel propellers for DP280, 290

D: Aluminium propellers for DP-S drives

E: Stainless steel propellers for DPX drives

F: Stainless steel propellers for DP-S drives.



BTW. I still have a slightly dinged pair of F7's in the basement, nothing that Bossler & Sweezey couldn't fix.

Peconic...thanx for all of the info...I am going to find out exactly what drive I have and take it from there.
I will update you when I find out where I stand and see about the set you have.

I'm curious about your drive and props. I have an older 30 boat with twin duroprops and aluminum props that need replacing. Going to go with stainless. My boat has small blocks, but am curious about how dependable the older duroprop drives are and how much abuse they can handle. If aluminum props were replaced with the same size in stainless, would the speed and/or rpm change?

Aggro: I had the F7s on a 23ft Stingray with 350 Magnum. The DP-S is a great and solid drive, I did hit many things, no complaints. Rumor has it it's rated up to 500 HP. Reindl uses them on their bat boats. Track super, and they are great in reverse.

The only problem is the price of the props. A set sets you back $1100. I always said they are making them at the Stockholm mint. Also, they are pretty thin, and any contact with ground seriously bends them out of shape.