...- U.S.-based offshore vessel provider Hornbeck Offshore Services Inc. has announced a debt exchange proposal ahead of its April bond maturity. - Under the proposed transaction, holders of the company's existing senior unsecured notes due 2020 and 2021 would swap them for new senior notes due 2023 and 2025. Some holders of the old notes may also participate in a capped cash tender. - The completion of the transaction hinges on garnering the requisite support from Hornbeck's noteholders and shareholders. - We are affirming our '##' (selective default) issuer credit rating on Hornbeck Offshore. - At the same time, we are lowering our issue-level rating on the company's senior unsecured notes due 2021 to '##' from '###' and are affirming our 'D' issue-level rating on the 2020 notes. In addition, we are revising our recovery ratings on both issues to '3' from '2' to indicate our expectation for meaningful (50%-70%; rounded estimate: 65%) recovery in the event of a payment default....