Prop Size for Volvo D Series Diesel

[dtol]

The following is in reference to discussions we had earlier on D4 prop sizes. It is from Thomas Kempe, a volvo teck that posts advice regularly on Boatdiesel.com

"Oddbjorn: If you bought this new, contact the dealer and Volvo and ask for sea-trial data. You should reach 3600 and if not they have to fix it for you. I assume you have a duo-prop and I do not think you repitch those and instead change props. You know some engines have had valve problems in Norway and if you do not clear this with Volvo in writing they will say you are over-propped if something happens. This may happen to boats and the buyer is not aware - do not let this slip away. Nimbus has a good reputation and they can work this out with Volvo also. Otherwise change it yourself and you get some for your old props. Better to be under-propped with this engine. Gott Nytt Ar."

It seems that some are more worried about losing a mile an hour at top end rather than propping the vessel so that the engine doesn't have to lug and allowing it to reach proper RPMs. I went from a G6 prop to a G3 prop to get my boat to where it needs to be when loaded.

Denny

[Salt Chukar]

Repitching

Denny,
I'm not a member of boat diesel, but what is that concern of having props re-pitched? There are prop shops that have been in business for years that repitch props for a fraction of the cost of new ones. I was told they can take nibral props one size and stainless two sizes. After looking at your boat pics from your other post I think I would have looked at the D6:eek: The nice thing is you have the slow idle speed around the harbor. Your chrome trimmed gauges are a nice touch also.

Chuck

[dtol]

Well the D6 is another 400lbs so the builder was very concerned about weight distribution etc. I don't know if the Volvo Brass alloy duo props can be repitched. Maybe so, and I just haven't heard about it. The point I was trying to make is how much importance Volvo and dealers and techs that work on Volvos place on propping the boats so that the engines can reach 3600 rpms at WOT. There is more about this in the Boatdiesel thread that I quoted from.

[FISHFACE]

ask Jerry at Seward Heavy Industrial, he's the volvo guy up here

[captaindd]

You have to do a sea trial to make sure the engines get to the right RPM. You will have to go up or down in pitch to meet that goal. I have never heard of anyone trying to repitch a dual prop. The prop shop in Washington would know if this can be done.

[akfishnut]

Dealers Supply Test Props

All dealers that sell the Volvo line will have several sets of test props.
It's in their best interest to make sure your engine has the correct props
mounted.

[potbuilder]

Well the D6 is another 400lbs so the builder was very concerned about weight distribution etc. I don't know if the Volvo Brass alloy duo props can be repitched. Maybe so, and I just haven't heard about it. The point I was trying to make is how much importance Volvo and dealers and techs that work on Volvos place on propping the boats so that the engines can reach 3600 rpms at WOT. There is more about this in the Boatdiesel thread that I quoted from.

Not to be a wise arse but what happens to the weight dist if 2 guys walk to the back of your boat when underway?? does it bog down??? The builder wimped out on that question in my opinion.
I've had some of my aluminum duo props(junk) repitched one size but i don't think they ever did a good job, i think it might have ended up being like 1/2 a size differance. I've since went to stainless props. One of the problems most prop shops have with repitching volvo props is that they don't really know how to convert volvo prop sizes C-4, B-3, you know what i mean ?? into the inches of pitch their pitch blocks are measured in.
If it was my engine i'd make sure it turned the 3600 rpm as suggested by volvo and then NEVER run it like volvo tells you to, i mean don't run it 200/300 under max rpm for cruise speed like volvo tells you to or you'll be running to a early rebuild. I'm gonna tell you again GET A PYRO for that rig if you want to know whats going on with your engine.

[dtol]

When you have 1800lbs of engine and you need to determine where to put 1600lbs of fuel, and 400lbs of water and kicker fuel and 400lbs of kicker, & other gear, plus other gear in the rear, 500lbs of people is irrelevent. Sounds dumb, but if you are a designer trying to reconcile all of the factors involved, every pound needs to be considered.

I believe in what you are saying relevent to trying to give the engine an easy life because it will be a longer life. Follow Volvo's recomendations for RPMs, I have found that almost all recomendations for Volvo props have been over estimated. On the west coast this has been done by the main distributer out of Seattle and Volvo will use what ever excuse they can to not pay. We need to protect ourselves and that means follow the Volvo specs!!!! Alaska Heavy Industrial in Seward doesn't have any test props and they will charge you $200 to change out a prop if your prop has been in the water.