The largest "swing" keel "production" yacht (ie. keel pivots/rotates into hull) is probably the Northshore Southerly 54rs. They have only just started construction, so if this does not count, then the next model down the 46rs is probably the biggest. Draught varies between 7 foot, to less than 3 foot with the keel up on the 46rs and it can be beached.
In terms of "custom" designed yachts, the Bill Dixon Yacht Design Company have made a 100 foot yacht with a swing keel named Liara II (Liara II actually has a tubular keel, meaning the lower half of the keel with the bulb is lifted into the out keel casing. It works in the same way a telescope does. But large yachts can accommodate swing keels). Coincidently, Bill Dixon designed the (hull) Southerly 46rs as mentioned above.
As for yachts with "lifting" keels (ie. keel moves vertically upwards) the biggest production may be the Hanse 630e which as the name suggest is 63 foot in lenght. Marten also producte a lifting keel yacht I belive. Wally have adjustable boards, as do products of many of the larger builders but it could be argued that these are custom, rather than production models as they all vary.
As for custom yachts, adjsutable boards are fairly common, the biggest may be Mirabella V, her draught can vary between 32 feet and 13 feet. Mirabella V is 247 foot in lenght and set numerous records upon completion of construction in terms of size, sail area, mast height ect.
The Southerly 57 is on the water at Southampton Boat Show and there is a 65 on the way.
The purpose of a keel in a sailboat are to generate lift to counteract the force of the wind. The keel converts the motion of the wind into a forward motion for the sailboat.
A centerboard is retractable, the keel is not. A centerboard is lighter than a keel. Please see the related link below:
the keel
Because It is not strong
it floats by the forces of the wind and the keel it helps it to float!
If you remove the keel, be aware that centre of gravity and stability will be affected.
A main longitudinal structure along the bottom of the sailboat called the keel. This is what prevents it from tipping over.
Have up to much sail, surf waves, or break off the keel.
A Dagger Board is a small removable board that acts as a Keel on a small sailboat.
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.
if your in salt water barnicals could have grown in the swing keel slot and are holding it in place. Worse case senario, it has rusted and in doing so has begun to expand as it rusts and is lodged in place. Good luck
The hull of a boat is the body of the boat. it is the part of the boat in the water. excluding the mast, boom, sail, rudder, keel, etc.