Yrvind ½ has 18 lead chambers. They are placed in three groups, six chambers in each group. They are situated to port and starboard and aft close to the transom.

The ones to port and starboard helps to control healing. In strong winds, to get more righting moment, six lead weights, each 15 kilos or 33 pounds can be shifted to windward, either all or some of them. In light wind, to dig in the chine runners deeper the weights may be kept to leeward.
The aft group is useful when running before gales with breaking waves. Weight placed so far back moves the center of resistance aft and makes the boat more course stable. Also as the mass moment of inertia increases with the square of the gyr radius the boat will much better resist pitch pooling. Naturally it will also be more easily pooped, but as the boat is strong and waterproof it is in my case a better choice.

The above picture shows the lead weights placed to windward. As can be seen, so placed they give a greater righting arm compared to, if the same wight in the form of a 200 pound man would have been placed on the rail.

This is how the starboard lead chambers look. (later I will add lockers on top of them)

Lifting the lid one can see one mock up weight with a wedge on top of it. When moving the weights from side to side they slide across the floor up on a wedge an fall down behind it. Then another wedge is jammed in filling the gap to the roof. After that a small door is closed keeping the wedge in place. Now they can not get anywhere even if the boat is capsized or pitch pooled.

The wedge which is placed on top of the weights.

A mock up of one of the 15 kilo lead weights with its stainless steel handle.

The door which keeps the wedges in place.

On its back can be seen the locking mechanism which keeps the door in its place

Its made of a piston hank. The pieces which holds the sail and attach it to the stay is cut of with a hacksaw. A piece of string is attach to the nob to easier get a grip on the piston.
I use these piston hanks to lock many lockers.