Better than a Pocket or Tunnel?

Pockets and tunnels have some problems,perhaps this easier to build and simpler design could solve many of them.

 

The Atkin reverse deadrise is also interesting as it may prevent the stern from sinking at under plainning speeds and with a box keel protects the prop when beaching .

 

What speed range is this intended for? Why are the edges rounded?

 

Better than a pocket or tunnel

There could be a lot of different versions, to give a better prop tip clearance or to allow a bigger prop or shallower shaft angle and even fit an I/O or shaft drive higher for S/P operation or just better shallow water operation.

The application would be better for an inboard where the weight forward would help keep a shallow plane angle but not so good with a heavy outboard on the transom with out interference plates or trim tabs.
There are many different options.
With a retractable shaft drive any potential damage the the shaft or prop
is eliminated with less drag from extra protection devices as the shaft would rise and fall with contact from any obstructions.

 

Better than a pocket or tunnel

Having curved edges helps water flow and reduces turbulence as different from
sharper edges on some tunnels and pocket designs which interfere with prop
efficiency (especially on turns) and can create aeration, also reduces the "running on rails" effect of some pockets and tunnels,easier and better steering.
There is no reason why high speeds would be problematic and the water pressure released from front of the device would assist flow to the prop by rising to the prop.

 

It is a design that has worked well for me.
I got frustrated with trying to design a perfect tunnel, and just bopped off a flat 8' long and 2' wide at the 14 deg. transom, gving the prop some 8" less draft.
The prop runs very cleanly, no "tunnel noise" and no cavitation bubbles in its wash.
The boat is somewhat underpowered, so I don't know really what would happen in high speed, but at wot 15 knots, it drags very little wake.

 

I am glad to see someone else has tried that design, and I tried several versions and think they were all better than any conventional tunnel designs which make a boat feel like it is running on rails.
The mistake that could be made is making the image free flow plans to big.

The amount of v or deadrise on a hull does dictate where the perimiter of the water flow will be.
As with most S/P configurations it is the depth of the rudder needed to steer a boat well that prevents
a boat from really shallow water operation. A deep rudder is needed about the same as a conventional subsurface drive at least.