A centerboard is lighter, therefore not as strong. The centerboard is retractable, the keel is not.
Please see the related link below:
A centerboard is retractable, the keel is not. A centerboard is lighter than a keel. Please see the related link below:
The distance between the bottom and the keel of a boat is the draught (British English).
Viking longships, starting in the 700s AD, had a mast with a sail. To make a boat with a sail stable, a keel is needed to counteract the tipping forces the wind places on the sail. Prior to the sail being added, longships did not require or have keels.
The wind foils around the sail; this provides lift, and pulls it along. The water must pass from the front of the boat toward the rear, passing the centerboard (or keel) and then the rudder, to provide steerage.
Sure...it all depends on the depth of the keel or centerboard (daggerboard). El Toros, for instance, have a relatively short centerboard and can easily sail in shallow water.
The extended keel or centerboard, the rudder, and the fore-and-aft rigging of sails all help a boat sail closer to the wind.
on the bottom
KEEL
The keel boat was invented to provide stability and maneuverability to boats, especially in rough waters. The addition of a keel helps prevent capsizing and allows for better control over the boat's direction.
The keel is important because it forces the boat to move forwards when the force of the wind on the sails might also be pushing the boat sideways. The keel stops the boat simply going directly downwind.
The distance between the bottom and the keel of a boat is the draught (British English).
The space between the boat's keel and the bottom is the draught.