Flopping on one side at speed

This is one of the issues people using Whale tail type products report when its not set up correctly, It has to do with the foil dragging in the water at speed. Normally when you take the foil off the problem goes away, this isn't the only cause by any means, but it is the easiest and cheapest to try as a first step.

 

Mybe make a flat surface in the back of hull bottom??

 

The problem is fundamental. Too much motor on too small a boat. A 16 foot boat of that type needs no more than 20 to 25 hp. Unless it is heavily loaded, it will run at a very respectable speed and be safer to operate than with an absurdly large and foolishly heavy engine. More than that, the economy of operation is a major factor. You said " a boat for the kids to play with" . You have given them a lethal toy. Trade the damned engine for a more sensible one.

 

Rubbish Messahbout ....I have a 16 ft runabout with 90 hp ..it runs to about 37 knots but you cruise nice at about 25 with the trottle back...others fit 150 HP to this boat...I still dont see how it can fall over if the back 1/3 is in the water on the plane...does it flip violently and quickly side to side as you steer like a jetski..? ( yes I know boats lean in the turn but they sit up straight when not turning)

No boat is for the kids to play with ...you need a lisence here for over 6 hp and be 16 ...

 

I had a 18 footer with a label on the transom saying 80HP max.

I put a 175 Merc on it. When I sold it he put a 200Hp on it.

It was a great bare foot boat, behaved perfectly but was'nt a kids boat.