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Roboat

PROPER-prop size?

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Good Day,

  I have a 2007 Signature 280 with the Volvo 4.3 OSi engine and now with new Volvo DPS-B1 OX drives (2.32) ratio as the replacement for the infamous XPD drives.What is the proper prop size and pitch sizing for these drives?

Thanks in advance...

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How many people & a rough estimate of the groups TOTAL weight  is required. That is how I pick a prop. Then the engines can rev up to   MAYBE GET ON PLANE.  WEight matters.

A 2017 is 6900 pounds dry. ADD 100 gallons of liquids ? 600 # ?    = 7500 # & 300 to 350 hp on the probably lighter hulls today. Yours might be pushing almost 8000 #...............

Edit ....Add the people weight to the 8000# for a get on plane weight 10 X 180# each =1,800# extra or about 9,800 pounds to climb onto plane.

Call www.propgods.com or www.ptprop.com  Ask for Technical support.

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My 186 SSI is 3200# with the 5.0 L 220 hp. add fuel & 1600 # of people.  A 4,160 # boat @ 42 GPS. Very clean bottom.

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Cyclops2..Thanks....I was really looking for what Chaparral would recommend or what prop size and what pitch other 280 Signature owners were running.I can appreciate the addition of fuel, water, and people in the determination of the optimum prop but I can't be changing and guessing at prop specs.I am looking for an average good performing prop for everyday cruising. The specs for this boat list it anywhere from 8200 lbs to 9500 lbs dry.Thanks for the info though, food for thought.

Regards

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Add up your numbers & get the degree of hull V  and width of the hull. You have a 225 hp motor.  That should get a worst case load onto plane.

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What pops and drive ratio came on the boat?

if I had to make a guess, I would start at 24 inch pitch. Volvo doesn't call out their prop pitch, so likely an F4.

brick

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Brick, I do not know specifically the prop designation but it appears to be too big as the back prop comes very near the exhaust port which in my estimation causes the exhaust to be disturbed as it exits causing a buzzing sound when on plane. The drives are Ocean X  2.32 ratio which were changed out last fall on the Volvo exchange program from the composite XDP drives.I only purchased the boat mid-July.

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The prop series, like F, come in same diameter just the pitch is different. Not likely that the prop fitted on your drive by the factory is of wrong diameter. Let's start with what props are on your drives now?

Your newer DPS-B drive uses props of newer series, FH or something like this. Go on VP site, or download their accessories catalog, and find out which line or lines of props are suitable for your drive and compare with what you have.

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Waiting to hear back from my contact, but should simply need to swap out current F series props with same FH series.

If memory serves, I think the 2007 Signature 280 used 2.20 gear ratio with 24" props on twin MerCruiser 4.3L MPI, so my gut says the boat was probably equipped with F5 props to compensate for the slightly higher gear ratio used by Volvo. Thus if you had F5 props and RPM was 4400-4800 RPM at wide open throttle with average load, than install FH5 props. If you're down on RPM, then switch to lower pitched FH4. If RPM is too high, then try FH6.

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Thanks, Sheherd1...The ratio on the Ocean X drives are 2.32 and I removed the rear props this morning to get the serial numbers and they were  F8 3851478 3M port side and  F8 3851478 7C starboard.I would believe these props were from the former XDP outdrives with modified hubs for the helical splines on the new drives. The reason I am looking for a proper sizing is that when on plane with this configuration it makes an aggravating buzzing from the props displacing water from the drive exhaust not totally out of the water but near enough to the surface to cause the noise.

Picton Ontario

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Nada..No boat races, used to have the Gold Cup races but not for many years now and boat shows have also disappeared. They did have a small out of the water show a few years ago up at the old WW2 Air Force training site up on the hill, now known as Loch Sloy Industrial Park featuring Miss Supertest.III .The Picton Harbour in itself does not offer much in entertainment or food services either. You have to walk into town or cab it.

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