The PowerKeel hull developed and tank-tested by Avia Design Group offers the
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.
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.
Note Bow wave,
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
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
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
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.