PowerKeel

The PowerKeel hull developed and tank-tested by Avia Design Group offers the following benefits:

Reduced Fuel Consumption
Very significantly reduced fuel consumption in the speed/length range from .5 to 2.00 (3 to 12 knots for a 36' boat)

 

Improved Seakeeping Ability
The unique hull/keel configuration offers excellent directional stability and strong roll damping effect.

 

Excellent Accommodation
By concentrating all machinery and tanks in the keel, the upper portion of the hull is available from end to end, allowing space for features such as a dinghy garage, large aft cabin, etc.

 

Protected Propeller and Rudder
Both propeller and rudder are protected behind the keel.

Basic Hull
9.4 Knots

Note Bow wave, 
stern turbulence

 

PowerKeel
9.4 Knots

Note flat bow wake,
reduced stern turbulence.


The attached data is from tank testing of the PowerKeel hull design.  The power keel is a large appendage which displaces about 70% of the total weight of the vessel. The upper hull is similar to a planing hull. The Bow pressure wave occurs under water and the the upper hull rides on top of it, suppressing the bow wave. The large keel volume can contain the engine and machinery,  tanks and batteries, resulting in a very low CG and a very safe offshore vessel. The propeller and rudder are completely protected by the keel, and a horizontal shaft line gives excellent propulsive efficiency.
 
In order to have a basis for comparison, we made a scale model of a 36' hull design without keel, tested it, then added the keel and tested it again.
 
Both versions were tested at 8000 kg. displacement and a variety of speeds.
 
To summarize the results, the PowerKeel version had less resistance at all speeds below 15 knots (on a 36' boat) with the best improvement between 9 and 12 knots.  The wake at 9 knots is impressively flat.
 
A standard bulbous bow hull where the bulb fairs into the hull gives best results at a S/L ratio of 1.1 (6.8 knots for this hull). This one gives the best results at S/L ratio 1.5 or 9 knots.
 
This hull ideally suits a long range trawler which would like to cruise efficiently at speeds higher than standard displacement speeds.
 
The tank test model was scaled to a 3' draft due to requirements of the first potential client. The hull would be even more efficient with a slightly deeper draft as the bulb should be submerged further. The prototype is designed for aluminum construction, therefore the hard edges on the keel.  A GRP hull would have a smoother shape. Ignore the styling shown as the PowerKeel boat could look completely different above the waterline.

We are seeking builders interested in incorporating this hull shape in to new models.  We can provide either complete design or hull only. Royalties are low and intended to encourage builders. For details please email below.