Hey guys I have question; I want to upgrade to four blade prop on my boat, is the pitch size the same or I have to go down one number?

What engine and hp? What prop do you have now and why the change?

Tom

 

Most drop one size, and most manufacturers have interactive tools to help guide you

Why?  I tried 2 of them they on my motor.  They didn’t make much of a difference.

12 minutes ago, Jig Man said:

Why?  I tried 2 of them they on my motor.  They didn’t make much of a difference.

What are you trying to achieve? What prop or props do you currently have or have you tried on what boat with what motor?

4 hours ago, WRB said:

What engine and hp? What prop do you have now and why the change?

Tom

 

I have 90hp mercury 2 stroke .Overall performance. I damaged my Mercury black max last year and need to exchange it anyway.so now I'm curious if is it worth to upgrate to 4 blade prop.

1 hour ago, Jig Man said:

Why?  I tried 2 of them they on my motor.  They didn’t make much of a difference.

Better performance? Never owned one , always 3 blade

4 blade will give you better bite, better holeshot, and a loss of top end.

If that's the case ,that's kind of what I'm looking for , even by sacrificing little bit of speed in the process.

You can also gain hole shot by removing/upsizing vent plugs from a prop - usually less sacrificing of top end

Was your old prop a stock aluminum 3 blade? Nothing but questions so what boat is this 90 Merc pushing? Your top end speed and time to get on plane (hole shot) has more to do with hull design, plane surface, gross weight and how the weight is distributed then the prop. When everything is right then the prop can fine tune performance.

Lets assume you have a 3 blade SST Lazer 2, 20 pitch 3 blade Merc prop. You trim the engine all they down and go full throttle, the boat should get up on plane quickly in a 100 yards, then you trim up the engine to 5,800 rpms at 50 mph. Does this discribe your boat?

Tom

2 minutes ago, WRB said:

Was your old prop a stock aluminum 3 blade? Nothing but questions so what boat is this 90 Merc pushing? Your top end speed and time to get on plane (hole shot) has more to do with hull design, plane surface, gross weight and how the weight is distributed then the prop. When everything is right then the prop can fine tune performance.

Lets assume you have a 3 blade SST Lazer 2, 20 pitch 3 blade Merc prop. You trim the engine all they down and go full throttle, the boat should get up on plane quickly in a 100 yards or then you trim up the engine to 5,800 rpms at 50 mph. Does this discribe your boat?

Tom

Sylvian Excursion 1600 with stock alum. 19 pitch prop. 

Center console fishing boat with deep V hull and flat bottom plane surface. We just lost 10 mph. Are the trolling motor batteries and cranking batteries located in the stren compartment? Does this boat have a mid boat livewell?

Since this isn't a performance type hull the top end speed isn't an issue. Weight distrubution is also limited, most of the storage is located along the sides with dry storage in thr bow compartment? Just guessing.

I think a 19P 4 blade prop should work for you.

Tom

PS, update just looked up this boat and it's rated for 175 hp, you have 90 hp! We just lost another 5 mph and added 1350 lbs dry weight. You are grossly under powered.

8 minutes ago, WRB said:

Center console fishing boat with deep V hull and flat bottom plane surface. We just lost 10 mph. Are the trolling motor batteries and cranking batteries located in the stren compartment? Does this boat have a mid boat livewell?

Since this isn't a performance type hull the top end speed isn't an issue. Weight distrubution is also limited, most of the storage is located along the sides with dry storage in thr bow compartment? Just guessing.

I think a 19P 4 blade prop should work for you.

Tom

Thank you Tom

17 minutes ago, Dan W said:

Thank you Tom

You missed my PS update, so what was you top speed and rpm's at wot?

Switching to a 3 blade SS prop might do you some good. A SS prop will have more cup, thinner blades that will create less drag, and less flex, but I don't know if flex would be an issue on a 90hp. If your local shop can't let you try different props, there are some prop rental sites that will charge around $50 to test props. That's better then shelling out $400 to find out the prop you just purchased isn't the optimum choice for your needs.

14 hours ago, WRB said:

Center console fishing boat with deep V hull and flat bottom plane surface. We just lost 10 mph. Are the trolling motor batteries and cranking batteries located in the stren compartment? Does this boat have a mid boat livewell?

Since this isn't a performance type hull the top end speed isn't an issue. Weight distrubution is also limited, most of the storage is located along the sides with dry storage in thr bow compartment? Just guessing.

I think a 19P 4 blade prop should work for you.

Tom

PS, update just looked up this boat and it's rated for 175 hp, you have 90 hp! We just lost another 5 mph and added 1350 lbs dry weight. You are grossly under powered.

I saw a max rating of 90. Not sure what boat you may have been looking at that states 175. I thought it sounded off when he had a 90 and others have 70s and 90s and you mentioned 175 max hp

5 minutes ago, Stephen B said:

I saw a max rating of 90. Not sure what boat you may have been looking at that states 175

Looked up the OP's boat, older boat as Sulvian makes pontoon boats now. 16'4" with 90 hp sounds correct thinking about it.

So the 19P SST 4 blade should work.

Tom

5 minutes ago, Stephen B said:

I saw a max rating of 90. Not sure what boat you may have been looking at that states 175. I thought it sounded off when he had a 90 and others have 70s and 90s and you mentioned 175 max hp

yeah I've never saw a 16ft boat rated over 100HP.  probably looking at an 18 footer

Just now, WRB said:

Looked up the OP's boat, older boat as Sulvian makes pontoon boats now. 16'4" with 90 hp sounds correct thinking about it.

So the 19P SST 4 blade should work.

Tom

Haha you scared me lol ?.