The Shark keel is not really a bulb keel. It's very broad and comletely flat on the bottom. The upper half is narrow/thin but it does become more bulbous in the bottom half. It's more of a modified scheel keel than a bulb.

A classic scheel keel is pictured (not a Shark). The Shark keel is broad and flat at the bottom like this but the upper half is narrow, then gets broad as you go down.