If your vessel has a title, you should contact the appropriate governing body in your state.
If your vessel is documented with the USCG, then you should complete this form for Transfer Exchange of USCG Documentation.
Remember: if the vessel has mortgages or liens against it, then you either must satisfy those or get the permission of the mortgage/lienholder. Submit that with your application above.
Depending on if you wish to exchange the vessel documentation for your own (or another Representative, Estate Heir, Administrators, and so forth) then you may also need to present a Certified Death Certificate and other evidence. For further information, you can reach us at info@usregistrar.us