Another Pontoon/Prop question

[Sliderhd]

Hello All,
Not new to boating but new to pontoons. My wife and I just bought a new Suntracker 22' Fishin' Barge. Been on the water twice (all day) .WOT My boat is running 23 mph(GPS) at 5000 rpm on glass smooth lake with me, wife and 3/4 tank fuel and normal fishing tackle. Going back to my bass boat days it was propped to 5900 rpm on a Johnson GT150(1988) Raker Prop. The manual for this engine says operating range is 5000 to 6000. I think I will need less pitch. Mercury prop selector says 16X12 ([FONT=&quot]16436CP1) Black Max or a 14X12 Spitfire. Using the rule of thumb I learned here I don't think pitch 12" will be low enough to obtain 5700 to 5900 rpm. Any and all opinions appreciated.Pictures attached
Engine 2017 Mercury 90 90ELPT CT 4S Gear Ratio 2.38:1 Loving the fuel mileage!!
Prop is a Mercury Black Max 78114CP1 CP13 16X13 cupped
Back of hull pic is with motor at high trim level just prior to ventilation. Not sure what the little V welded to bottom of motor pod is for. Any ideas?[/FONT]

 

[Scott Danforth]

I would raise the motor a bit first to optimize the height, then adjust the prop.

 

[Sea Rider]

Toons as any other recreational boat should ride parallel to water level. Distribute deck weight evenly. Trim OB to 90?, go for a wot spin, check at which lower leg height is water flow passing by at fast displacement speed, will need to stay there, raise or lower leg which isn't known yet. Will discover that on a wot test on flat calm no wind water cond by pulling head out transom/engine mount, whatever to check that. Report your findings..

Ideal lower leg height is for water flow at speed to skim right under upper water deflector plate, the plate that shows the protruding lip, where sharp angle begins. Forget all about rule of thumb anticav plate height parameter.

After correct OB height optimization can go for a prop maximization to a lower pitch to pull wot revs around middle to max wot rpm factory range. Once both are correctly dialed, will achieve full 90 HP out of that OB. Probably will need to drop 2 pitches to rev around max wot range. As this is not rocket science, will need to test prop under current load at wot..

Happy Boating

 

[SkiDad]

i personally would try the 14x12 spitfire ? I think the smaller diameter will get your rpm up. just an opinion