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Any idea on 'Elephant Ear' propellers for Alpha 1 and what size it should be...

M

Mars Lano

New member
Hello!
My 1999 model Bayliner 2452 is a stern heavy type boat. Actually the WOT is somewhere between 5000-5100 which is too high. The OEM recommends 4800 max. This boat normally comes with 220 HP carburetor engine by the factory but I replaced it with a new 260 HP 5.0L MPI engine but the Alpha 1 sterndrive and the 15x17P 3 blade aluminium propeller stayed. May be, this is why it over revs, I am not sure. With this prop, I can reach 33 knots in calm water.

My problem is; getting on plane too slowly and consequently I drop off the plane too easily. Instead, I would like to get out of the hole faster, stay on the plane even at low rpms and hopefully get a better fuel mileage.

I would love to hear your advice for choosing the right size propeller for my gear. While searching, I’ve read good reviews on so called ‘Elephant Ear’ propellers which was a design formerly developed by Volvo Penta. Does anyone knows where to look to find a generic one compatibile with Alpha sterndrives?
I would also appreciate if you have better ideas.
Thank you very much!
 
You have a fairly heavy boat that is on the verge of needing twin engines, You already have a not very pitchy prop at 17. Going to a 19 or 21 will really make hole shots a real drag. On top of that the 5.0 isn't a particularly stellar performer. I don't think you can "prop" yourself out of this. Your expectations may just be a bit rosy for the setup you have. Are you "flooring it" when you accelerate or slowly building speed? Have you fooled with trim settings at all? How much cargo do you have on board including passengers? Tried trim tabs? A lot of time the slow to plane issue isn't the horsepower but things like weight distribution, dead rise and the hull design, and wind resistance from high deckhouse.
The Bayliner hulls are made with low dead rise so that they are more comfortable at anchor. The center of gravity shifts rearward when you accelerate, which digs a deep hole that is harder to get out of.
 
“A lot of time the slow to plane issue isn't the horsepower but things like weight distribution,”
X1
My buddy has a cuddly cabin Stingray, single engine. With 4-5 adults on board, if a couple are seated in the rear seats, it’s very slow to plane. Moving them forward to the cuddly entrance makes a huge difference in holeshot. Once on plane they can be reseated.
This is evident even on small boats. I keep a little 14’ jonboat at the dock, it will quickly plane with two adults on board…if the passenger is seated appropriately.
 
I wonder who made a decision to go with less power than what originally came in the boat.
Bayliner is notorious for underpowering new boats for pricing reasons. So this boat was underpowered when new.

So for choices to overcome slow/lack of planing may be,

1. Install hydralic trim tabs which when fully down will help greatly with quicker planing. There are also spring loaded vs hydraulic so do your research.

2. If they still are available, a Tourque shift propeller. These start at a very low pitch and at a certain RPM (set by springs) will change to a higher pitch. Example- 15 pitch at idle and once 3-4000 rpm is reached it shifts to 19 pitch.

3. Some may say to install a "whales tail" but Mercduiser says NO. That would be your call. It will help but may cause steering issues at higher rpms/speeds.

The correct power train should have been a 5.7 mag ~270-280 hp and a Bravo 2.
The Bravo 2 uses a very large diameter prop and would pop that boat right out of the water and on plain in no time.

We used to do this upgrade to 24-28 ft cuddies that were under powered.
Worked very well!
 
o2batsea said:
You have a fairly heavy boat that is on the verge of needing twin engines, You already have a not very pitchy prop at 17. Going to a 19 or 21 will really make hole shots a real drag. On top of that the 5.0 isn't a particularly stellar performer. I don't think you can "prop" yourself out of this. Your expectations may just be a bit rosy for the setup you have. Are you "flooring it" when you accelerate or slowly building speed? Have you fooled with trim settings at all? How much cargo do you have on board including passengers? Tried trim tabs? A lot of time the slow to plane issue isn't the horsepower but things like weight distribution, dead rise and the hull design, and wind resistance from high deckhouse.
The Bayliner hulls are made with low dead rise so that they are more comfortable at anchor. The center of gravity shifts rearward when you accelerate, which digs a deep hole that is harder to get out of.
Click to expand...
Hi, I totally agree with your facts on the design and dynamics of this boat coming from its very nature unfortunatelly. The only pro is; it has one of the greatest interior space for a boat at its size: 24.5 feet only! Well, what I try to know is; if there could be a prop that can achieve better dynamics with the current set up. Indeed, the old prop is really old and I need a spare, too.
I am 52 so I do not floor it, as well:) I am not fond of horsepower or top speed either. The torque, steering factors and overall dynamics are more important to me. While searchin on web, I've seen there is a consensus that upgrading to 4 blades would also help for better hole shots. Compromising 2-3 knots on top speed is not a big deal for me and I would like to give a try. With a better prop design and the right size for the purpose, we can achieve better dynamics, no?
I searched net on 'elephant ear' design propellers but could't match something useful. May be a wrong keyword to search. I've also read that it was first developed by Volvo Penta but I don't think that it can be used my Alpha1. I bet there are many good American aftermarket products with the same design concept that can get along much better with Alpha1. I would be happy if you have any ideas on where to look.
Thank you very much!-:)
 
I am older than 52. When I want my 19’ bowrider on plane, (powered by a 4 banger Volvo Penta SX & 19” three blade aluminum prop), I “floor it”.
Going easy on the throttle, if loaded is a sure way to take forever to get on the step. When I flew float planes in the Arctic, we always used full power to get on step as quickly as possible. The only exception was the turbo beaver with the “dash 6” engine, (a turbo prop built by Pratt & Whitney). On a hot summer day it would reach the temperature limit before the torque limit. The extra fuel used by going full power is the same as plowing for 1/2 a mile under partial power.
My buddies 21’ Stingray was repropped with a 4 blade. It makes a small difference in holeshot, with a corresponding small decrease in top end speed. For him, weight distribution is the key to getting on step.
The 14’ jonboat referenced above, it’s used for fishing & testing small motors.
With a puny 6hp Johnyrude, 2 adults, I go full power to start, it hops up on step,then throttle back. I’ve used both 2 blade & 3 blade. GPS shows almost the same top speed,
Moving to a well running 8hp, (33% more power), gives better holeshot at more weight, but only a couple more mph.
In your case, being underpowered, try moving a couple of the biggest people forward, they can stand at the cuddly entrance, & no one in the rear seats. Once on plane, they can move anywhere.
 
as far as tweaking your propeller....best bet is find a local dealer that has a good selection, in stock, and will let you try them out.

The torque-shift props are NLA (new) so that's not an option any longer...

a 4 blade will likely be the best bet and one with the largest diameter that will fit...

If you are not worried about top speed, you can always change the gear set in the outdrive...
 
You will probably not see any seat-of-the-pants improvement with a 4 blade over a 3 blade. The best thing you can do is employ the services of a propeller shop. They can assist with prop selection and you will be able to try several before you decide.
The thing that makes the boat spacious on the inside is exactly what makes it an underperformer on the waves. You trade one thing for another.
 
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