Glastron with 85hp Johnson Finding the right prop

Devonaaron

Seaman Apprentice
Joined
Aug 1, 2010
Messages
32
I currently have a 16 foot glastron trihull deep v weight is about 700 pounds without anything I would say in total I'm not having more than 4 people on with me I will generally be taking just the girl out nothing crazy. I am always going long distances like 20 or 30 miles round trip I like going fast and geting where I wanna go the thing is my boat just is not heavy at all for the 85hp Johnson that's pushing it currently with a 13x17 old OMC stainless prop the thing is my boat reaches a higher top speed trimed up but it makes so much noise I know it's over reving so I was thinking about buying a higher pitch stainless prop when I trim it all the way down it sounds to be running around 5000 rpms but I don't use it that way I get like 33 knots top speed and trimmed down like 27. I just don't get it because I don't want to overload my motor but how do I get the highest pitch prop with my normal trim settings witch is generally high to reach the high speeds. I have a tiny tach but for me to be in the back of the boat geting readings while someone is driving is just something hard to get due to the waves and fear of going in the cold weather. I have a pretty good ear for rpms but that's not a accurate way at all also should I get a 4 blade I'm running it in choppy waters also and I put a hydrofoil stabilizer on it so I can go at a low rpm nice but 17 mph docent cut it nice to do it sometimes though. Any ideas on what I should get or do I was also thinking about geting a 140 Hp powerhead on it to really go but that's in the far future I wanna see what I can do with my 85hp powered. Thanks guys te me what you think about my situation.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,088
Re: Glastron with 85hp Johnson Finding the right prop

Ayuh,... Without reliably knowing the rpms at Wot,...

There Ain't No answers to yer questions....
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: Glastron with 85hp Johnson Finding the right prop

Without your actual rpm there is no way to safely select a prop.You need to be able to tell how well the present prop works and how well the selected prop works.
Correct prop selection will improve performance and protect the health of the motor.
 
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