What prop on 2000lb 18ft 3.0l Merc Sea Ray?

gixxerjim

Petty Officer 2nd Class
Joined
Mar 14, 2007
Messages
171
Banged up a pre-1983 (old old design) 21p prop on my 1988 Sea Ray Seville, with that prop I ran 40mph with 2 guys and a full tank of gas at 4500 rpm.

Local prop expert says a 19P new Merc would be the right choice for overall performance, Merc prop selector says 21P new design....

There are a lot of brands out there, is Merc the way to go? I will be buying a 3 blade aluminum I think.

19, 20 or 21P and what brand please for this underpowered boat?

Thanks for any advice and experience you can relate!
 

hwsiii

Commander
Joined
Jan 25, 2009
Messages
2,639
Re: What prop on 2000lb 18ft 3.0l Merc Sea Ray?

Jim,welcome to Iboats prop forum and we will try to help you as much as we can, but there is certain information that is needed in order to help you. The following form has all of the information that is needed to help you with your problems in finding the right prop. If you do not know all of the information that is asked for on the form please give us the most information you have available as I have a program I designed to find the right prop for any planing hull boat that needs this information, and most other people who are trying to help you will need the same information. It requires time to find all this information when we have to look for it and in my defense I expect you to be willing to expend as much effort in finding the right prop as I do. We hope to be able to help you get the exact prop you need for your particular uses, and this information is required to do that.
It is not as simple to pick the right prop as most people coming to this forum think it is, that is why we ask so many questions, it is for your benefit we ask all these questions. And if you have a stainless steel prop or are changing to one the blade geometry of the prop can make a lot of difference in speed and RPM.

Iboats Boat and Motor Info

1. Year, make and model of boat
2. Length, width and base weight of boat, look for boat decal on back of boat
3. Number of people and gallons of gas normally on boat
4. What do you use the boat for
5. Is it a Deep Vee and if so how many degrees of deadrise
6. Year, make and model of motor
7. HP and gear ratio of motor
8. Manufacturer?s recommended WOT range
9. Anti-ventilation Plate height above keel of boat if it is an outboard in inches
10. Does it have a hydrafoil or trim tabs
11. Make, model, diameter, pitch and whether SS or aluminum prop
11. WOT RPM and speed from prop, how much gas and how many people in boat for test data
The only thing I ask of you is to come back and give me a report of WOT RPM and speed for my database.

H
 

gixxerjim

Petty Officer 2nd Class
Joined
Mar 14, 2007
Messages
171
Re: What prop on 2000lb 18ft 3.0l Merc Sea Ray?

1. Year, make and model of boat
2. Length, width and base weight of boat, look for boat decal on back of boat
3. Number of people and gallons of gas normally on boat
4. What do you use the boat for
5. Is it a Deep Vee and if so how many degrees of deadrise
6. Year, make and model of motor
7. HP and gear ratio of motor
8. Manufacturer?s recommended WOT range
9. Anti-ventilation Plate height above keel of boat if it is an outboard in inches
10. Does it have a hydrafoil or trim tabs
11. Make, model, diameter, pitch and whether SS or aluminum prop
11. WOT RPM and speed from prop, how much gas and how many people in boat for test data
The only thing I ask of you is to come back and give me a report of WOT RPM and speed for my database.

H

Thank you for helping, here is my info:
'88 Sea Ray Seville 180BR
18ft long x 90" wide x 2000 lbs
Usually 2 adults and 3 small kids on boat, full 20 gallons of gas
Use for tubing, a little slaloming, general boating
Not a deepV
'88 Merc 3.0L 135 hp 4cyl, alpha 2:1, 4200-4600rpm
no planing accessories (yet)
with an old 21p Merc 14" dia prop and 2 adults fulltank of gas hit 40mph and 4500rpm, this prop is pre 1983 in vg condition at test time, smooth water
 

hwsiii

Commander
Joined
Jan 25, 2009
Messages
2,639
Re: What prop on 2000lb 18ft 3.0l Merc Sea Ray?

Jim, buy a solas aluminum 4 blade, you will lose a little top end speed and RPM, but it will give you a great hole shot and acceleration.

H
 

gixxerjim

Petty Officer 2nd Class
Joined
Mar 14, 2007
Messages
171
Re: What prop on 2000lb 18ft 3.0l Merc Sea Ray?

Sounds good, what pitch do you recommend?

Like I said Mercury website calculates a 21P but stock was like 19 or 17 back in 1988.

Maybe props have gotten better so more pitch is workable now than what the motor could turn with props made in 1988?
 

hwsiii

Commander
Joined
Jan 25, 2009
Messages
2,639
Re: What prop on 2000lb 18ft 3.0l Merc Sea Ray?

Jim, this is the prop to buy your RPM will stay about the same and you will lose a little top speed but you will have a better hole shot and load carrying. I would have recommended a 20" pitch but they don't have one.

Price: $103.99
You Save: $43.01
Compare: $147.00
Discount: 29.3% Off
Add Amita Aluminum Propeller 1513-143-19 To Your Cart

Propeller Specifications:
SKU:#1513-143-19
Manufacturer: Solas
Brand: Amita
Material: Aluminum
Diameter: 14 - 1/4?
Pitch: 19?
Blades: 4
Rotation: Standard (Clockwise)

H
 

gixxerjim

Petty Officer 2nd Class
Joined
Mar 14, 2007
Messages
171
Re: What prop on 2000lb 18ft 3.0l Merc Sea Ray?

Thanks for your advice, I will post results after I get the prop....
 

hwsiii

Commander
Joined
Jan 25, 2009
Messages
2,639
Re: What prop on 2000lb 18ft 3.0l Merc Sea Ray?

Thank you.

H
 
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