Bayliner Explorer 2270 prop selection

[rkcarguy]

I've acquired a 1981 Bayliner Explorer 2270 with the AQ120B and 270 drive.
The guy I got it from had thieves get to it, and the prop, whale tail, and electronics where all stolen.
Does anyone know a good starting point for a prop for this?
I've seen anywhere from a 15x15 to a 16x13 used but that's the only 2 posts I could find and no one stated their wot rpm with those props.
I was thinking a Solas amita 14-1/2 dia x15 pitch 4-blade might be a good place to start but I'd rather be underpropped instead of over.
I'm hoping someone on here has a 2270 and could help me out...

The technical information:
Semi-displacement hull(not a planning hull)
4000#'s dry weight
120HP 4-cylinder Volvo OHC
2.15:1 Volvo 270 outdrive
Boat is ~23' Long, Hardtop with Alaska bulkhead

 

[Robbabob]

Re: Bayliner Explorer 2270 prop selection

To save us from searching out the HP of the engine and length/weight of boat, please let us know and we'll give a decent starting point. Realize, you'll have to start somewhere with a prop size no matter what, so hopefully you'll be able to test a prop without having to purchase.

We look forward to assisting!

 

[rkcarguy]

Re: Bayliner Explorer 2270 prop selection

Edited with boat stats

 

[rkcarguy]

Re: Bayliner Explorer 2270 prop selection

I'm gonna have to just try the 14x17 3 ear and see how it goes, at least I can adjust from there according to how wot ends up.
A 15x13 4-blade would be awesome but can't find one in VP anywhere.

 

[rkcarguy]

Re: Bayliner Explorer 2270 prop selection

The 14.5x17 3-blade aluminum netted me 5000rpm @ 21.6 knots GPS verified, with a fuel tank of fuel, kicker, full freshwater tank, 2-house batts(4 total)and some fishing gear. I beleive this is a pirahna aluminum prop, it's got some cup to it and has slots in the trailing end to ease water transfer to the prop cone.
Seems to like to cruise at 4000rpm(torque peak for this camshaft incidentally), at about 17 knots. Pretty impressive for a 120HP 4-cylinder in a 4000# boat.

 

[steelespike]

Re: Bayliner Explorer 2270 prop selection

Looks like you hit it pretty close.With a 4,000 dry weight I do wonder if the tach may be a little optimistic.I guess if the hole shot is reasonably strong and it holds slow plane, holds up to added weight, leave well enough alone.

 

[rkcarguy]

Re: Bayliner Explorer 2270 prop selection

It sounds right and seems accurate...it's my 2nd 4-cylinder OHC powered boat. Although less displacement, the camshaft is the same one as the engine in my other boat and it sings nicely until ~4500rpm and then starts to choke a bit above that.
Remember that the 2270 is a semi-displacement hull, meaning part of the boat cuts thru the water instead of being all up on plane. I was surprised as well, because the prop is the same one that works good on my 19' cuddy with the AQ131a and I thought it would fall short of wot.

 

[rkcarguy]

Re: Bayliner Explorer 2270 prop selection

Got 4 people on the boat and it was overpropped. I'm going to have to look into the 14-1/2x15 or see if I can find a 15x13 4-blade somewhere.
Boat still cruised at 15kts + but would only WOT at 4400rpm around 18kts. Nice thing about a non-planning hull is I just pulled the throttle back and cruised around 12 knots to be easier on the engine. No pinging, loss of power, or damage is apparent.

 

[rkcarguy]

Re: Bayliner Explorer 2270 prop selection

Ordered a Solas Amita 15-1/2x13 3-blade prop from this site to try out, will arrive thursday so we'll see how it does.
For light loading I should be able to use the 14x17, but with four people and all the crab pots I need more a tug boat prop.

 

[kalger]

Re: Bayliner Explorer 2270 prop selection

I also have 1981 2270 aq120b 270 outdrive. My boat has difficulty planing unless 1 or 2 people on board. I am awaiting results for the new prop you ordered to see if I need to do the same. what kind of fuel consumption do you get? at what speed? thanks

 

[rkcarguy]

Re: Bayliner Explorer 2270 prop selection

I ended up about the same with the 15.5x13, but gained some low speed maneuvering.
For now, I've had to tweak the timing back conservatively and run what I got because I can't get any smaller prop. Set it at 6* idle and ~33* total, where the manual calls for 10* and 36-38*.
I pull the throttle back a little and cruise around 3800-4000rpm, tides and wind can vary my mpg alot, but typically 2.6-3.4mpg depending on conditions.
My loading hasn't helped, we had 4 people, 6 crab traps, full fuel and water tanks, and an 80qt cooler and ice on board along with a bunch of fishing stuff.
Cruise speed seems to be ~18 knots on good water down to ~14 bucking a headwind and lumpy seas. GPS verified.
I have a whale tail I may try, wanted to avoid drilling more holes in the cav plate but if it helps it helps......