prop help for 87 searay DA with twin 350s

[lkeriedog]

I have a 1987 searay DA with twin 260hp/350 chevy motors. I have the original 3 blade 14x19pitch alum. props on the boat. I want to help the take-off, hole shot if you may. Several people have told me to go with a 4 blade prop that is 14 1/2 x 18pitch because it will give me what I want. I see a couple choices in this size. The Mercury QA2184x and the Michigan Vortex wheel. Are either one of these manufacturers better than the other? Is either the XHS or the Flo-Torq II hub better than the other? This is a heavy boat and I want to make sure I don't blow out the hub when taking off. Or, any other suggestions on a prop/hub combination would be greatly appreciated. I don't have the money to buy SS props, or I would. Thanks for any help with my questions. Steve

 

[Summer Fun]

Re: prop help for 87 searay DA with twin 350s

My 1987 30ft Sea Ray with twin 260hp 350's likes the 15 x 15 props .
Top speed by GPS at WOT 51mph with just me and 2 small friends.
With 10 friends and 5 beers coolers at 3700rpm's. .
View attachment 50974

Welcome to iboats.

 

[45Auto]

Re: prop help for 87 searay DA with twin 350s

Top speed by GPS at WOT 51mph with just me and 2 small friends.
With 10 friends and 5 beers coolers at 3700rpm's. .

Not bad. 3700 RPM with 15" pitch props and zero slip is 35 MPH with a 1.5 ratio drive and 39 MPH with a 1.34 ratio drive. In other words, the over 40 MPH that you're claiming in your photo at 3700 RPM isn't possible. You're easily running 20% to 30% slip on your boat.

You may want to check your GPS, 51 MPH would require about 5400 RPM with 15" pitch props and zero slip. Again, not possible.

I have the same boat, 1987 300 DA with twin 260's. Running High Five 19" pitch props gives low 40's at WOT (4800 RPM). Can't say what the difference in acceleration would be with stock props, mine had the High Fives on it when I got it.

 

[lkeriedog]

Re: prop help for 87 searay DA with twin 350s

Sorry, I should have stated the size of my boat. It is a 27 foot boat. the 270 model. I don't have a MPH gauge on my boat, just an RPM gauge, so I don't have a clue how fast it is. I don't care about gaining any speed, just more hold shot because it takes too long to plane out. That is why the 4 blade props were recommended.

 

[rbh]

Re: prop help for 87 searay DA with twin 350s

I have a 1987 searay DA with twin 260hp/350 chevy motors. I have the original 3 blade 14x19pitch alum. props on the boat. I want to help the take-off, hole shot if you may. Several people have told me to go with a 4 blade prop that is 14 1/2 x 18pitch because it will give me what I want. I see a couple choices in this size. The Mercury QA2184x and the Michigan Vortex wheel. Are either one of these manufacturers better than the other? Is either the XHS or the Flo-Torq II hub better than the other? This is a heavy boat and I want to make sure I don't blow out the hub when taking off. Or, any other suggestions on a prop/hub combination would be greatly appreciated. I don't have the money to buy SS props, or I would. Thanks for any help with my questions. Steve

We are running the same 14x19 but the 4 blade and am only reaching 30-33+-
But it sure comes up on plane fast.
I would like to try the 15's and see if there's any difference??????

 

[Summer Fun]

Re: prop help for 87 searay DA with twin 350s

You may want to check your GPS,

45Auto, You just popped my bubble. . Damn GPS.

It is a 27 foot boat. the 270 model

I'll bet if you took a tape measure to it, It'll measure out to 30'6" over all length or real close to it. .
Back then Sea Ray did some weird measuring on OAL.

Ask anyone that stays at a marina where they bring out the tape.
They don't care whats on your title for factory length. .

 

[rbh]

Re: prop help for 87 searay DA with twin 350s

45Auto, You just popped my bubble. . Damn GPS.

Maybe you have it on kilometers instead of MPH?????
it can happen.

 

[lkeriedog]

Re: prop help for 87 searay DA with twin 350s

So no one out there has an opinion one prop is better than another between Mercury/Quicksilver and Michigan Vortex props or the hubs? Another brand maybe?

 

[Summer Fun]

Re: prop help for 87 searay DA with twin 350s

They are all good until you hit something !!
Most prop shop will let you try some different props out for free.