How much would this effect performance?

[steelespike]

Re: How much would this effect performance?

Couple of pictures of the prop on my neighbor's boat. Ends of a couple of the blades are chewed completely off. This was done over 4 years ago, picture was taken last summer, he's never done anything about it. Didn't make a bit of difference in the performance of the boat. Exact same GPS top speed, fuel flow, etc.

Odds are it will cause premature failure of the gearcase seals and or bearings.
Pretty costly compared to a prop repair.GPH wouldn't change.Though I have a feeling that
GPH for a given speed is is more than with a good prop.ie: best cruising speed is different
rpm and or gph.

 

[cribber]

Re: How much would this effect performance?

48-78120-19 is a Mercruiser 14x19" prop. Here is the link to Iboats 19" pitch mercruiser props.

http://boatpropellers.iboats.com/Me...andard&**********=273702690&*******=602584451

Start with what came with the boat and take it from there. I have 3 props for my Glastron for different purposes. One is stock to go with her when the time comes to part company, one for fishing, and one for pulling tubes and skiers.

 

[Fun Times]

Re: How much would this effect performance?

Ok, here's what I found on the prop...

48-78120-19

I assume the 19 means pitch..what about the other numbers?

Given the price difference is $10 why would anyone NOT get 4 blade opposed to a 3?


ps....I removed and cleaned off the prop. Apparently the kitchen sink is not the place for this...who knew??

Here is the part number history of this prop starting with number 7 being the oldest one, The number has Superseded over the years.
Item Supersession Chain:
Row Class Part Number SS Level Disp Description
1 48 832830A45 00 ACT BLKMX 14 1/2R19

2 48 832830ARA 01 SS BLMX 14 1/4R19

3 48 78120A45 01 SS ALUM 14.0X19.00

4 48 78120A40 02 SS ALUM 14.00X19.00

5 48 78120A4 03 SS PROPELLER

6 48 74874A4 04 SS PROPELLER

7 48 73508A4 05 SS PROPELLER ASSY

Here is the price and the Availability of the prop if you wanted to buy a one new today from a mercruiser dealer, And if the dealer was out of stock and had to order it from the warehouse this is where it would be coming from.
78120A45 is Superseded to 832830A45
Class:#48
Supersession
Item Number: 832830A45
Status: Active
Weight: 9 lbs
Description: BLKMX 14 1/2R19
Package Quantity: 1
MSRP: $179.49
003 - FOND DU LAC,WI, Has Over 10 in stock.
073 - ATLANTA,GA, Has Over 10 in stock.
075 - FRESNO,CA, Has Over 10 in stock.

 

[hwsiii]

Re: How much would this effect performance?

Paul, if you gear ratio is 1.65, please verify this. Then I recommend a Solas aluminum 4 blade prop in a 17" pitch, and you should turn right at maximum RPM with very little prop slip and do close to 40 MPH.

Iboats has this prop and it will cost you about $ 110

IBOATS price and SKU number
Price: $109.99
You Save: $37.01
Compare: $147.00
Discount: 25.2% Off

Propeller Specifications:
SKU:#1513-145-17
Manufacturer: Solas
Brand: Amita
Material: Aluminum
Diameter: 14 - 1/2?
Pitch: 17?
Blades: 4
Rotation: Standard (Clockwise)
Usually Ships Within: 1 Business Day


Prop Picker

3. Number of people and gallons of gas normally on boat
50% - 2 adults and 1 child and lets say...15 gallons of gas (500-600lbs)
50% - 4 adults and 3 children and 15 gallons of gas (1000 lbs) (max capacity is 1050)

4. What do you use the boat for
Currently my son is 3 so we're not big into water sport just yet, but pull a tube and some skiing when friends visit.
50% - cruising, site seeing
50% - mostly tubing and some skiing

For your particular uses this will be the prop you can use ALL of the time and it will work well for your uses and needs, instead of having to change props regularly.

And take the whale tail off, you won't need it, and it probably slow you down that deep in the water.

You also might try reading this for a better understanding of changing props for better performance.

http://forums.iboats.com/showthread.php?t=365653"]http://forums.iboats.com/showthread.php?t=365653"]http://forums.iboats.com/showthread.php?t=365653

H

 

[paulspaddle]

Re: How much would this effect performance?

Here is the part number history of this prop starting with number 7 being the oldest one, The number has Superseded over the years.
Item Supersession Chain:
Row Class Part Number SS Level Disp Description
1 48 832830A45 00 ACT BLKMX 14 1/2R19

2 48 832830ARA 01 SS BLMX 14 1/4R19

3 48 78120A45 01 SS ALUM 14.0X19.00

4 48 78120A40 02 SS ALUM 14.00X19.00

5 48 78120A4 03 SS PROPELLER

6 48 74874A4 04 SS PROPELLER

7 48 73508A4 05 SS PROPELLER ASSY

Here is the price and the Availability of the prop if you wanted to buy a one new today from a mercruiser dealer, And if the dealer was out of stock and had to order it from the warehouse this is where it would be coming from.
78120A45 is Superseded to 832830A45
Class:#48
Supersession
Item Number: 832830A45
Status: Active
Weight: 9 lbs
Description: BLKMX 14 1/2R19
Package Quantity: 1
MSRP: $179.49
003 - FOND DU LAC,WI, Has Over 10 in stock.
073 - ATLANTA,GA, Has Over 10 in stock.
075 - FRESNO,CA, Has Over 10 in stock.

Hey Boat Tech,

That's exactly the kind of information I cut/paste and put into my boat file on the hard drive.

Thank You!

 

[paulspaddle]

Re: How much would this effect performance?

Paul, if you gear ratio is 1.65, please verify this. Then I recommend a Solas aluminum 4 blade prop in a 17" pitch, and you should turn right at maximum RPM with very little prop slip and do close to 40 MPH.

Iboats has this prop and it will cost you about $ 110

IBOATS price and SKU number
Price: $109.99
You Save: $37.01
Compare: $147.00
Discount: 25.2% Off

Propeller Specifications:
SKU:#1513-145-17
Manufacturer: Solas
Brand: Amita
Material: Aluminum
Diameter: 14 - 1/2?
Pitch: 17?
Blades: 4
Rotation: Standard (Clockwise)
Usually Ships Within: 1 Business Day


Prop Picker

For your particular uses this will be the prop you can use ALL of the time and it will work well for your uses and needs, instead of having to change props regularly.

And take the whale tail off, you won't need it, and it probably slow you down that deep in the water.

You also might try reading this for a better understanding of changing props for better performance.

http://forums.iboats.com/showthread.php?t=365653"]http://forums.iboats.com/showthread.php?t=365653"]http://forums.iboats.com/showthread.php?t=365653

H

Thanks for taking the time to run the numbers. Interesting.

I agree with the recommendation. Brand and style although I am surprised you recommended 17" pitch.

It's also interesting that you suggest taking the whale tail off. I thought this was there to help with the hole shot by keeping the bow down? Albeit it does seem to make sense that it would take 'something' away from the top end.

I need to verify the gear ratio. The number I gave I got from the service manual. i think I remember reading that there is a manual way of figuring this. Will have to look for that.

I'm going to have the boat indoors and heated for the weekend and will do some more poking and exploring....then off to the frozen back 40 for the winter.

Thanks for the link....

PW

 

[Fun Times]

Re: How much would this effect performance?

Here is a link to another good 4 blade prop to keep in mind that works varry well also, It's from mercruiser, And It's called the alpha 4 blade. It comes in either 16, 18, or 20, pitch.

http://sites.mercurymarine.com/portal/page?_pageid=126,49589,126_50268&_dad=portal&_schema=PORTAL

Class:48
Supersession Item Number: 834852A45
Status: Active
Weight: 9.813 lbs
Description: ALPH4 14 1/2R18
Package Quantity: 1
MSRP: $211.79
Price
Warehouse Quantity:
003 - FOND DU LAC,WI, Has Over 10 in stock.
073 - ATLANTA,GA, Has Over 10 in stock.