Shoal Keel Aground
Peter Burke of Fredericksburg, Virginia, asks:
"We recently went aground in a creek off the Potomac River in my Hunter 28, which has a shoal keel that draws 3 feet 6 inches. We were unsuccessful in our attempts to break free, but fortunately a marine police boat and a rescue boat came along within minutes to assist. Surprisingly, the rescue boat had to pull hard with its twin 250hp outboards, and the police boat had to circle to create some wake before we were afloat again.
My previous sailboat had a standard keel of the same depth. I wonder now if a shoal keel is more difficult to free up than a standard keel after a boat runs aground."
Don Casey replies:
The only inherent difficulty in freeing a short keel from the bottom is that heeling lifts the keel less because of the shorter lever arm. Most shoal keels, however, also have a ballast bulb or some flair at the bottom to increase weight down low. This makes the bottom of the keel broader, which increases friction between the keel and seabed when the boat is aground.
The shoal keel on your Hunter 28 not only has a wide bulb at the bottom, there are also wings on either side of the bulb. Viewed from below this keel has an uncanny resemblance to an anchor. The wings dig into the bottom like anchor flukes and make it harder to heel the boat to lift the keel. The hollow between the wings and keel can also create suction that grips the bottom tenaciously. Ironically, though many may think a shoal keel allows them to pay less attention to water depth while sailing, the opposite may be true.