planning depth

[glenn property of pam]

a tunnel hull boat claims to plane in 4" and sit in 11" of water (craiglist). So im confussed if the prop is 12" round then how can the boat plane in 4" or does it mean that the boat can plan is 4" of water under the hull. I keep hearing all of these claims of how shallow some boats can run which would make sense if they were jet powered but these guys are running outboards so what am I missing.

 

[Frank Acampora]

Re: planning depth

I have seen a video of one of these "flats" boats running in water that was just over the ankles of a person standing off to the side of it. These guys jack up the engine so only one prop blade is in the water at plane but honestly, I don't know how they get cooling water, even a low water pick-up would be too high. They must have a secret for that.

 

[Bondo]

Re: planning depth

I have seen a video of one of these "flats" boats running in water that was just over the ankles of a person standing off to the side of it. These guys jack up the engine so only one prop blade is in the water at plane but honestly, I don't know how they get cooling water, even a low water pick-up would be too high. They must have a secret for that.

Ayuh,.... It's a Hull mounted pickup tube,...

1s I've seen were on the transom, just peekin' into the water stream comin' from under,...

 

[smokeonthewater]

Re: planning depth

also the tunnel design of a flats boat is unlike any other tunnel hull and actually LIFTS water up to where the prop is... in effect it works a LOT like a jet

 

[Home Cookin']

Re: planning depth

on many "tunnel" boats the motor is up in a cavity .

a lot of shallow water claims are exaggerations, but with a flat hull you can run in water that is as deep as the cavitation plate down; the hull may only be an inch below surface. Also when you run over soft mud you get some extra tolerance.

And water pressure in shallow water raises the boat, too.

 

[NSBCraig]

Re: planning depth

A tunnel hull flats boat has the motor sitting up higher so the the prop is above the bottom of the boat. None of the prop is out of the water and a steady flow of water is surrounding the lower end. It doesn't need anything special for cooling etc.

4" of water is quite common for one when it is on plane. 11" is about average floating. Getting on plane still takes more water, but taking off in a circle out of a deeper hole helps.

These boats are designed for this purpose.

They also take the most abuse of any type of boating. The shock wave of the boat bouncing slams bang into the boat off the bottom. Way worse than offshore racing stress gets put on them every time the run shallow. Check out the boat carefully if your going to buy it.