Unreasonable accumulation. Noncompliance with the provisions of section 511 of the Act or the regulations in this part relative to the utilization of the deposited amounts may also, inasmuch as the provision of section 511(f) of the Act is then inapplicable, warrant an examination to ascertain whether such amounts constitute an unreasonable accumulation of earnings and profits within the meaning of Part I (section 531 and following), Subchapter G, Chapter I of the Internal Revenue Code of 1954, or corresponding provisions of prior law. If amounts are deposited and the fund maintained in good faith for the purpose of construction, reconstruction, reconditioning, and acquisition of new vessels, or for the liquidation of purchase-money indebtedness on such vessels, such amounts will be deemed to have been accumulated for the reasonable needs of the business.
26 CFR § 2.1-23
Noncompliance. The amount of the gain which is that portion of the construction reserve fund otherwise constituting taxable income under the law applicable to the taxable year in which such gain was realized shall be included in the taxpayer's gross income for such taxable year for income or excess-profits tax purposes, if -
(1) A portion of such fund is withdrawn for purposes other than -
(i) The construction, reconstruction, reconditioning, or acquisition of a new vessel; or
(ii) The liquidation of existing or subsequently incurred purchase-money indebtedness to persons other than a parent company of, or a company affiliated or associated with, the mortgagor on a new vessel or vessels; or
(2) The taxpayer fails to comply with the requirements of section 511 of the Act or the regulations in this part relating to the utilization of construction reserve funds in the construction, reconstruction, reconditioning, or acquisition of a new vessel, or the liquidation of purchase-money indebtedness on such a vessel.