fast inflatable

johnny mav.

Cadet
Joined
Nov 26, 2011
Messages
19
I have a 12ft novarania inflatable with a vee hull and a 70 hp evinrude what prop would you recomend for top speed
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
11,047
What!!!! What's the max HP is the 12 Ft Rib rated for ? Was it rigged at a dealer or by an extreme boater ? Such size Rib with a 70 HP is surely over rated ? Needed Data for the rest of the equation :

-How many souls will be on board ?
-Current prop diam/pítch, number of blades ?
-Motor WOT RPM range factory stated ?
-Max achieved WOT RPM as loaded ?

To test the last two will need to buy an induction tach for a 3 cylinder motor, install it next to the tiller grip, program the spark firing sequence and go testing the Rib at open water.

Happy Boating
 

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dwco5051

Lieutenant Commander
Joined
Sep 14, 2008
Messages
1,685
It has been a boring winter and I would love to go along on that test ride. That boat is rated at 30hp max. A little excitement to take my mind off shoveling snow.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
11,047
It has been a boring winter and I would love to go along on that test ride. That boat is rated at 30hp max. A little excitement to take my mind off shoveling snow.
A 70 HP will blow not only your mind away, include yourself out of the Rib. Have you tested the combo package previously at wot ? The issue with a 70 HP motor it's darn s too heavy, will need a heavy champ to sit as a bow mask up front to balance and distribute the deck load evenly across the entire hull. If not the boat will achieve a bow up attitude.

Personally wouldn't dare install a 70 HP motor on a 3.65 Mtr Rib rated for a 30 HP motor, max would be a 40 HP one. At wot that boat should have a nervous behavior specially if tiller driven which don't know if it's the case ?


Happy Boating​
 

Stinnett21

Petty Officer 2nd Class
Joined
Jun 24, 2012
Messages
166
I assume he's talking about an old Johnrude looper. Probably no heavier than the modern 40 4stroke. Sounds like a fun setup. Get ready to wear ear protection and goggles. She's gonna fly!
 
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