4.3 prop

[Devin2680]

I have a 18 ft vip vision with a 4.3 2bbl and a 14.5 19p stainless prop in excellent shape, top speed with 4 adults is 43 mph via gps at 47 4800 rpm with the trim all the way down. Trimming up puts me to about 5100 but no increase in speed. Do I need more prop or does this sound about right? Also I'd like to get it home hold a plane at a slower mph what should I do? Thanks all

 

[Bondo]

Ayuh,..... Welcome Aboard,..... Sounds like ya need a 21" prop,.....

Wot numbers are taken with a light load, 1/2 tank of fuel, 'n trimmed for proper runnin',....

With the trim all the way down, yer plowin' the water,....

 

[steelespike]

It does appear you need a 21" prop.Do you trim down for reduced throttle operation?
If you struggle to maintain plane at reduced throttle you might consider a 4 blade prop
in a 19"This may reduce your rpm and may cost some top end speed as well.
But a 4 blade should get on plane quicker,maintain plane at reduced throttle and may handle better around the dock.
May feel smoother.

 

[Devin2680]

Thanks guys the prop is a quicksilver brand, would having it cupped be enough or should I just go ahead and jump up to a 21? I'd like to see 50mph from this boat I'd possible. Empty weight is 2300lbs. Also thinking of adding smart tabs.

 

[Maclin]

"Also I'd like to get it home hold a plane at a slower mph what should I do?"

Tabs, like Smart Tabs or some hydraulics with some auto-smarts make for good teamwork with a 4blade for this.


Also, not sure I like the sound of this condition ... "Trimming up puts me to about 5100 but no increase in speed." Make sure you are not just blowing out the prop into the foamy water at that level of trim, most props have to run in water and not half in half out.

 

[Devin2680]

The property isn't coming out of the water it goes up to 5100 with just a few bumps of the trim up. With the trim down from the windshield back is still in the water, with the trim bumped up from just behind drivers seat is in the water. If that makes sense.

 

[Maclin]

Seems like you are on top of that, very good. I usually see the speedo move ever so slightly when I hit that sweet spot on the way "up" on the trim.

 

[Devin2680]

No Title

This is the boat. What should the top speed be?

 

[Maclin]

On the trailer, I would try to keep it under 80