I see you are building Gary Webb’s “ Annie” from bearospaceindustries. Gary has included keel weight information for his various designs in the written instructions.

Displacement 20lbs/9Kg from the Annie Particulars

If you email Gary directly, he will get back to you shortly with answers to your questions.

You will need to be more specific if you expect a sensible reply.
Let us know the details of your enquiry so we can understand what it is you need to know.
😉