Advice needed on prop selection for Volvo Penta 290 DP

KnottyBuoyz · Mar 9, 2006

Hi Guys Looking for clues/guidance on the proper prop selection for my Volvo Penta AQ271A (350 cu in) and VP 290 Duoprop. I missed this thread entirely, sorry. All the background discussions are here.... Topic: Any Volvo Penta duoprop experts here? I phoned a half dozen marine repair shops today and nobody has a test set of props I can use/rent to help select the right set so I'm still left with having to make an educated (I hope) guess. Does anybody know what the pitch change is between the various Volvo Penta duoprops? I'm assuming it's about 2" for each step-up/step-down. I.e. from a B4 to a B5 would be an increase in 2" of pitch. Thanks guys. Your help is greatly appreciated.

stevens · Mar 10, 2006

Re: Advice needed on prop selection for Volvo Penta 290 DP

What if you contact the dealer and promise to buy the prop that works out the best? Surely, he won't stick you with the wrong set if you don't hit it right on the first try? Otherwise, this guide might be of help: http://www.volvo.com/NR/rdonlyres/2D2F5550-D247-4F3D-BE18-B8D3E71BEAA6/0/Prop_guide_2005_2006.pdf Starting with your expected speed, you would prop up or down accordingly. For example, in the table on page 4 of this brochure, it says that if your AQ271 /VP 290 had an expected top speed of 40 mph, you would start with a B5 alu prop, or on page 5, a C5 steel prop. Calculating backwards (using this calculator: link ) on the numbers from the same table, it would seem that a B1 corresponds to an approximate 10P and a B8 to an approximate 25P. That's a jump of approx. 15 inches across 7 sizes, i.e. approx. 2 inches per size step.

KnottyBuoyz · Mar 10, 2006

Re: Advice needed on prop selection for Volvo Penta 290 DP

Hi Stevens Thanks for the info. Exactly what I've been looking for. Apparently, for the dealers near me, try and buy isn't something they've ever practiced. I intend to buy online from the US anyways. There are still a few other factors I want to check before I make a decision. Boat is being lifted next week for bottom painting so I'll know the exact weight. Trim tabs, slightly undersized, were stolen so I want to replace with slightly larger. Probably leaning towards the B4 set to take some strain off of the running gear and engine during holeshots. Not worried about top end and I don't think cruising speed/fuel economy will be severely affected. Again, many thanks for the links.

stevens · Mar 10, 2006

Re: Advice needed on prop selection for Volvo Penta 290 DP

Glad to be of help. However, I just went back and read that first thread of yours where you say that your AQ271 /VP 290 currently tops out at 42 knots @ 4000 RPM with a set of B6. Those numbers don't fit very well with the table in that Volvo-brochure. Are you sure of the speed and RPM figures? Also, are you sure you have the right 1.95:1 gear ratio? Anyway, this might be worth checking out before you end up spending money on a complete range of B3-B4-B5 props....

KnottyBuoyz · Mar 10, 2006

Re: Advice needed on prop selection for Volvo Penta 290 DP

Hey Stevens I'm not totally absolutely positively sure the props are B6. They're an old set of test props someone stuck on before I got the boat. The stamped #'s don't match anything in the VP literature. They've been reworked so many times I doubt they're anywhere close to their original specs. I've hand cranked the engine in gear 1 rev and measured the prop rotation. It's very close to 1.95:1. Given the year, make, model of the outdrive and engine combo it should be correct. The speed is pretty accurate and can approach 45kts going downstream, w/+2.5Kt current, measured with GPS and chart plotter. 45kts is way too fast for this boat. Your sage advice is well taken. I'm going to do some more investigation before I invest any boat units on props. My main concern is getting the boat out of the hole and up on plane without putting a lot of strain on the running gear. Too bad it isn't a merc outdrive. I'd have a million options around here to correct the problem. There's a nice set of C5's on a Doral in our boat yard, Hmmmmm? Maybe I should just sorta borrow them for a lil' while, eh? *evil grin* Thanks again. I'll keep you posted.

stevens · Mar 10, 2006

Re: Advice needed on prop selection for Volvo Penta 290 DP

Too bad it isn't a merc outdrive. I'd have a million options around here ...

I understand that Mercury accessibility may be better in your part of the world. Now, I have a Mercury Alpha drive and really, really wish I had a Volvo duoprop drive instead. They seem so much better in so many ways. I've bought a few props on eBay (including some duoprop A5 props for a friend) from the Great Lakes Skipper. Worth checking out. With your set-up and speed, I think I would have tried a set of C5 (maybe C6) first. It seems to me that going all the way down to B4/C4 is way too low. Here are some: eBay1 eBay2 Good luck - and please do post back here when you've sorted it out.

KnottyBuoyz · Mar 13, 2006

Re: Advice needed on prop selection for Volvo Penta 290 DP

Hey guys. I'd like to take this opportunity to thank everyone, Reel Poor, Pine Island Fred, Marinemech1, Stevens and especially Don S for helping me solve this riddle. You guys are great. Based on the tips and info you guys were able to provide I've decided to purchase the B5 set of aluminum props. The boat was weighed on Saturday when it was being prepped for bottom painting and it's exactly what the literature said, 4400 lbs. Half fuel, half water, no bodies, etc. I'll let you know what the results are when we dunk the boat in the water in a couple of weeks. Again, thanks guys. Much appreciated.

KnottyBuoyz · May 27, 2006

Re: Advice needed on prop selection for Volvo Penta 290 DP

A quick thanks to everybody who helped me make the right prop selection. B5's were the ticket. Very smooth acceleration to plane in about 6 seconds, no vibration, no lumbering or hitting the wall at 2800 RPM. Speed's down a little but not much. Overall a very big improvement. WOT 4400 RPM on spec. You can feel the engine isn't working as hard against all the over pitched props. Thanks again. Rick

KnottyBuoyz · Jun 17, 2006

Re: Advice needed on prop selection for Volvo Penta 290 DP

New Policy - No Towing Remember those nice new props I put on two weeks ago? Well there not so nice now. It's blowing 25 knots and this lil' sailboat tries to get out of the marina and through the gap to the reach that leads to the St. Lawrence River. Everybody that's been in the marina knows you have to split the gap dead centre or risk getting hung up. Well this guy missed the center and guess what? Nobody else in the marina w/power boat. My first instinct was to just go home but my conscience wouldn't let me alone and silly me just had to help. Well, long story short, we tried to pull him but boat goes sideways into the bank chewing up my brand new props. Yup, the ones I've been saving for for 3 years to get. *sigh* So, told Lori, next time I suggest towing somebody she has approval to slap me silly. Sorry sailboat guys but I can't risk wrecking more equipment because you misjudged the weather. Just for the record, we don't have anything like TowBoat commercial services anywhere near here. Lesson learned. Policy set. Props will be rebuilt so it's not a great loss. Rick

KnottyBuoyz · Jun 17, 2006

Re: Advice needed on prop selection for Volvo Penta 290 DP

So, does anybody know what the general rule is for prop rebuilders? I mean, if say 30% of the blades are gone the rest is scrap? I hauled mine off and the fwd prop is pretty messed up. I'd estimate 25-30% of the blades are gone. I know some of these prop guys are good but there must be a point where they have to draw the line.

Almeja · Jun 18, 2006

Re: Advice needed on prop selection for Volvo Penta 290 DP

>"So, told Lori, next time I suggest towing somebody she has approval to slap me silly." IMHO: You still did the right thing by helping. Mariners help mariners in trouble. You never know when you might be the one desperately needing the other end of a towrope. Of course, as captain you do have to decide if you are putting your boat in danger... and sometimes it may be a tough call. Biggest beef here: The other boater should have offered to pay for your props. Decent people will offer to pay for damages others incur when saving their butts. Does he know you damaged your props?

KnottyBuoyz · Jun 18, 2006

Re: Advice needed on prop selection for Volvo Penta 290 DP

Yup he knows. Toss'd me $200 but I handed that in at the marina office and told them to hold it for him. He'll get the final bill if/when the props can be repaired. Worst he's looking at is $400 Cdn for the fwd prop which took the brunt of the damage. I'll probably still continue to help but I'm going to get myself a proper towing bridle and hawser. At least 150' should do it I think. I heard he only had one day to get from Iroquois to Gananoque which is hmmmm? 70 nautical miles against a 20 knot wind and a 3 knot current in a 26' sailboat w/15 HP yanmar. I think he should have planned his trip a bit better. I was even more ticked when I heard that. As I was pulling the props he was driving off in his Escalade so I don't think $400 will break him. I'm a poor civil servant and it took me 3 years to save up enough to buy the new screws.

Advice needed on prop selection for Volvo Penta 290 DP

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