PDQ OWNERS FORUM

WE JUST PURCHASED A 2002 PDQ 34 ' Island Time in january,love the boat, the boat came with 4 bladed props 16x11 and a half, with these props , I could not achieve a cruise speed of 11-13 knots. I took the original 3 blade props which came with the boat,16x13,had them reconditioned and installed them. The boat is like a different boat now, it does cruise at 11-13 knots. My question is that if i take the 4 blade props and have them repitched to 16x13, can i achieve the same speed. I keep reading on the forum how much better the 4 bladed props are. Also , is 3200 rpm a safe cruise rpm without stressing the motors, 75 hp. With the 3 bladed props, I can achieve3600 rpm, with the 4 bladed props, i can achieve3500 rpm

I am far from an expert on this, but you have two possibilities. For a constant diameter, if the pitch is too small, your engine should run up to maximum RPM before you reach the boat speed you expect. If the pitch is too great, your engine will fail to reach normal full throttle RPM and still not reach the expected boat speed. Your post did not indicate which problem you have.

I would not attempt to re-pitch anything until you get some more detailed answers from others here who have been through this.

hi,

if your 3 bladed props are 16x13 why do you want to go to 16x14 on the 4 bladed props? i'm not sure that a prop shop will will be able to get 3" more pitch out of your 4 blades.

we have 75hp, 3 blades, and run all day long at 3350-3400 and do 13-13.5 knots. we currently have 3200 hrs on the engines.

Sorry, i meant to write 16x13 on the 4 bladed props

Island Time, please re-read my post and tell us which of those problems you have.

I also have a 2002 PDQ 32. I recently repowered with the new Yanmar 80 Common rail engines. General Prop sized the props. They are 4-blade 18x13. .060 cup from radius 5 out through the tip. At wot (3200) speed is 19.5-20.5 mph. At cruise (2800) I get 16-17mph, without the dinghy I cruise around 18mph. I just topped the fuel tanks and fuel burn was 3.44 GPH. 90% of the time I was cruising at 2800rpm.

Captain Ron
2002 PDQ

hi ron,

what was the total cost of re-power?

Duetto, engines and installation were approximately $33,000. 4 blade 18x13 props were an additional $1,600.00

hi ron,

who did the conversion?

Duetto, All engine and systems work was done by Select Yacht in Sarasota. We also replaced the gen with a 6.5 phasor. I added a electroscan sewage treatment system, new water heater, freezer and cooler on bridge,AC, bilge pumps including 2 midship, sea stairs..etc.
Gregg at Stuart Yacht awlgripped Captain Ron's hull light blue. The topsides were painted Snow White. Gregg also reinforced the davit.

I am also questioning if I am over propped. We purchased Catbo (formerly Tar City Star) in February 2016. It is a 2006 and has 75 hp engines with 3 blade props. I have no idea if they are original or not. At the time of the survey the boat cruised 14 knots at 3200 rpm. Max RPM was 3638 on the port engine and 3534 on the starboard. The boat was lightly loaded other than full fuel and 5 people on board. Am I over propped?

On a somewhat separate issue, we are only getting about 3500 port and 3400 starboard right now. The engines do not have any black smoke, fuel consumption is good, all fuel filters are new and the boat has been fairly lightly loaded when we use it. normally full to half fuel, perhaps half a load of water, partial to half in the holding tank and two people on board. We have a diver come monthly to clean the bottom and have tested the boat within a day or two of it being cleaned. Any thoughts?

Thanks, Alan

I should add my props are 16 x 14 and that is all I know about them.

hi alan,

your max rpms seem low. i would be looking to pick up 200/300 rpms respectively. i would err on the side of more rpms. i think yanmar would say the same. we have a 2003 with 75 hp / 3 blade props. when we got our boat 11 years ago we had numbers much like yours with the same dia/pitch. we had them repitched to 16 x 13. after that, we can easily get to 3700+ with fairly full fuel, water and stores. we cruise all day long @ 3350-3400 and get 13.5-14 knots.

John,

Thank you for the thoughts. It will give me a starting point.

Alan