Boat bounces a lot in the water....

[Newbie@boats]

When I tilt the motor all the way down the boat will not bounce in the water, when I start planing out and tilting the motor up the boat will bounce a lot and will not stop....

Would the hydro-foil on the motor cause this?

Any ideas....?

And I did take the boat out without the new regi and didnt have any problems since there were no marine patrol on the lake....

 

[ondarvr]

Re: Boat bounces a lot in the water....

That's the way it works if you raise it up too high.

Some boats are very sensitive to weight distribution, so move stuff around and see what helps.

The foil wouldn't make it do that, but could create other issues if you don't need it, or if it hasn't been set up correctly. Just take it off and see what happens.

 

[Mike Robinson]

Re: Boat bounces a lot in the water....

... when I start planing out and tilting the motor up the boat will bounce a lot and will not stop...

Sounds like your are describing porpoising. I agree with ondarvr, try taking the foil off and see if things improve. Trim tabs will often help porpoising if it's excessive.

 

[tschmidty]

Re: Boat bounces a lot in the water....

My boat did that a lot as well, it's a pretty light boat. Keeping it trimmed down will help some and getting trim tabs will pretty much eliminate it (at least it did for me). Honestly, like a lot of others have said, Smart Tabs pretty much transformed the way the boat rode and handled, stays flat whne accelerating to a plane, doesn't porpoise and turns are more stable. And the Hydrofoil will accentuate it since it will tend to hold the tail up more. Remember too that trimming out is a pretty limited range. If it starts porpoising trim it back in (Doc, it hurts when I do this. Then stop doing it...).

 

[180Fisherman]

Re: Boat bounces a lot in the water....

Trim the motor up until just before the porpoinsing starts. Most likely that is where your motor should be anyway.

 

[nlain]

Re: Boat bounces a lot in the water....

My original boat never had a porpoise problem until I put a StingRay fin on it, then I had to be real careful how I trimmed it out. If you do trim too high it can cause this also, with or without the foil. Take the foil off and try it without, see what happens, if it starts, trim back just a little at a time until it quits. Proper trim should give you the most speed at any given rpm. I am a Smart Tab fan, I have them on my boat, they do everything advertised.

 

[Jvitto]

Re: Boat bounces a lot in the water....

I've had this issue for a few years on my 175 Osprey Aquasport with a Johnson 90. I'd bought it used and never thought about it much. If I opened it up on smooth water and tried to trim it would immediately porpoise. I recently damaged my prop and looked up the boat to find that the existing 17", 14 degree pitch was not spec. I changed it to a 17" 13 1/4 degree prop.
The boat no longer porpoises. I also have much more power getting out of the hole and on plane with noticeable handling difference ( for the better).
On the top end, I need to trim to get the same speed I was getting before (30, 31 mph) To be honest, I don't get up to those speeds often. Must be showing my age.

 

[RWilson2526]

Re: Boat bounces a lot in the water....

When I tilt the motor all the way down the boat will not bounce in the water, when I start planing out and tilting the motor up the boat will bounce a lot and will not stop....

Like the old joke with the doctor goes...It hurts when I do this...than do do that.