Opinion for the Court filed by Circuit Judge GINSBURG.
Dissenting opinion filed by Circuit Judge SILBERMAN.
GINSBURG, Circuit Judge:Appellants are owners and operators of small, unsubsidized vessels engaged in the Alaskan oil trade. They challenge a Maritime Administration (Marad) waiver decision which temporarily allowed two subsidized, very large crude carriers (VLCCs) to operate in this domestic Alaskan trade. The district court denied appellants’ request for a preliminary injunction and simultaneously granted Marad’s motion for summary judgment. See American Trading Transportation Co. v. United States, 610 F.Supp. 457 (D.D.C.1985). We conclude that, in granting the permission appellants challenge, Marad interpreted its waiver regulation in a manner inconsonant with the governing statute. We therefore vacate the judgment summarily entered against appellants and instruct the district court to return the case to Marad for further consideration consistent with this opinion.
I.
The Merchant Marine Act of 1936, 46 U.S.C. § 1101 et seq. (1982) (the Act), was enacted to promote a well-equipped and efficient merchant fleet owned and operated by United States citizens and supported by domestic shipbuilding and repair facilities. See id. at § 1101. To advance these purposes, the Act requires every vessel sailing under this nation’s flag to be owned by United States citizens, and staffed by a domestic crew. See id. at §§ 65b, 1132(a). The construction and operation costs of United States ships, however, are substantially higher than those of their foreign counterparts; for this reason, U.S.-flag vessels would not be positioned to contend with foreign-flag vessels in offering shipping services, absent government intervention or protection. Congress therefore created two separate programs to shelter U.S.flag ships.
First, the “Jones Act,” as it is popularly known, restricts the domestic trade — the carriage of goods between ports in the United States — to U.S.-flag vessels built in the United States. See 46 U.S.C. § 883.1 *945Thus protected from low-cost foreign competition, these ships are otherwise unsubsidized. Second, the Merchant Marine Act provides for subsidies to offset the higher costs of building (construction-differential program) and operating (operating-differential program) in the United States. See id. at §§ 1151 et seq., 1171 et seq. Ships constructed and operated with the aid of these subsidies are positioned to compete with foreign-flag ships and therefore ply the foreign trade.
The subsidized ships, because of their cost-structure advantage over unsubsidized U.S.-flag vessels, are prohibited from engaging in the domestic trade except under narrow, specified circumstances. See 46 U.S.C. § 1156. This case involves an excepted circumstance. The statutory exception at issue allows the Secretary of Transportation to approve a temporary waiver of the domestic trade ban for a particular subsidized vessel, for a period not to exceed six months in each year, if consent to the temporary transfer is “necessary or appropriate to carry out the purposes of this [Act].” Id. The consent to transfer is conditioned upon the repayment of a proportionate share of the construction-differential subsidy and the forfeiture of any operating subsidy during the period of domestic employment. See id.; see also id. at § 1175(a).2 The Secretary delegated this waiver power to Marad.
In 1977, Marad issued a regulation to guide certain exercises of its waiver power. See 42 Fed.Reg. 33035 (1977) (codified at 46 C.F.R. Part 250). The regulation applies only to waivers for subsidized ships over 100,000 deadweight tons (dwt) to participate in the longest leg of the Alaskan oil trade: from Valdez, Alaska to the Panama Canal. See 46 C.F.R. Part 250 (1985). The regulation is primarily procedural: it details the information a waiver application must include; and it contains a timetable for comments by interested persons, replies by the applicant, and a decision by Marad. See id. at §§ 250.3, 250.4. Any “competitor” may file a formal protest, and Marad is obliged to consider objections so presented. See id. at § 250.4. A “competitor” is defined by the regulation as the owner or operator of an unsubsidized U.S.-flag vessel eligible for operation in the domestic trade. See id. at § 250.2(c).
The regulation sets forth no substantive criteria controlling Marad’s appraisal of a waiver application. Marad has stated, however, that it follows the standard contained in § 506 of the Act; that provision instructs the administrator to determine whether the consent to transfer is “necessary or appropriate to carry out the purposes of this Act.” See Opinion of the Maritime Administration on Approving Two Applications and Denying One Application at 43, reprinted in Joint Appendix (J.A.) at 64 [hereinafter cited as Marad Opinion].
An additional, more precise criterion may be derived from the regulation’s instruction that, to qualify for a waiver, an applicant must aver that “suitable vessels of a competitor would not be available.” See 46 C.F.R. § 250.3(d). Marad has apparently interpreted this provision as according to “suitable” unsubsidized vessels an absolute veto over any waiver for a time period *946during which such vessels are or will be unemployed. See Brief for Seatrain et al. at 26-27; cf. Atlantic Richfield Co. v. United States, 774 F.2d 1193, 1204 (D.C.Cir.1985) (holding that it was “appropriate” for Marad to condition a waiver on the continued unavailability of suitable unsubsidized vessels). The regulation defines a “suitable” vessel as one 100,000 dwt or larger and qualified to participate in the domestic trade. See 46 C.F.R. § 250.2(h).
In the waiver proceeding at issue, Marad accepted applications from three subsidized YLCCs.3 Upon issuing a public notice, Marad promptly received comments and protests from the owners of many unsubsidized vessels, some larger than 100,000 dwt and some smaller. After a round of responses, counter-responses, and rebuttals, Marad granted waivers to two of the applicants. See Marad Opinion at 59-61, reprinted in J.A. at 80-82.
The small, unsubsidized tankers — the appellants in this case — argued to Marad that its regulation was substantively and procedurally invalid. They contended that their competitive interests should be considered and that those interests warranted denial of the waiver applications. See Marad Opinion at 12-13, reprinted in J.A. at 33-34. In response, Marad stated that its regulation had been promulgated pursuant to correct procedures and that substantive guidelines were not needed in the regulation because they were supplied by the Act itself. See id. at 43, reprinted in J.A. at 64. The agency then swiftly rejected the protests of vessels under 100,000 dwt; such vessels, Marad declared, lacked “standing” to protest. See id. at 51-56, reprinted in J.A. at 72-77.
For the ruling that the small vessels had no standing to complain, Marad relied upon a line of its own decisions dismissing protests of vessels under 100,000 dwt because they failed to qualify as “suitable” vessels for the Alaska-Panama trade and, therefore, were not within the category of “competitors” authorized to protest under the regulation. See id. The agency then recited evidence indicating that vessels under 100,000 dwt are less suitable for this particular long voyage and that such vessels, in fact, account for only a small part of that trade even when no subsidized ships participate. See id. Next, without discussing the substance of the small vessels’ protest, Marad concluded that waivers for two subsidized VLCC’s were necessary and appropriate to serve the purposes of the Act. See id. at 58-61, reprinted in J.A. at 79-82.4
The owners of the small, unsubsidized tankers sought review in the district court. That court granted summary judgment for Marad. It held that appellants could not challenge the procedural regularity of the rule’s promulgation seven years after the fact, see American Trading, 610 F.Supp. at 461-62, reprinted in J.A. at 90-91, and that the tonnage limitation (100,000 dwt) had not been shown to be arbitrary, capricious, or inconsistent with the statute, see id. at 462-63, reprinted in J.A. at 92-93.5
*947II.
We turn first to the question whether the owners of small, unsubsidized tankers have “standing” under Marad’s regulation to protest a waiver application. Marad’s position on this issue is an enigma. The agency’s opinion in this case includes a statement that owners of tankers under 100,000 dwt do not have standing to protest. See Marad Opinion at 51-52, reprinted in J.A. at 72-73. Presumably for this reason, Marad refused to confront and rule on the substance of appellants’ protests. In a cryptic footnote to its opinion, however, Marad offered this second thought: “[T]hese protestors can and obviously do participate to some extent in the agency action but under the rule they cannot block approval of the applications.” Id. at 52 n. 8, reprinted in J.A. at 73. And at oral argument, counsel for the agency backtracked further. Counsel suggested that we view the reference to “standing” in Marad’s opinion as simply an unfortunate word choice. He represented this to be Marad’s position: appellants did have standing to protest but, unlike the owners of unsubsidized tankers over 100,000 dwt, they lacked power to block or veto a waiver.
We find it difficult to reconcile Marad’s footnote and its counsel’s position at oral argument with the body of Marad’s opinion. If the appellants had standing to “participate to some extent,” why was the substance of their protests ignored in the agency’s decision?
The section of Marad’s opinion concerning the protests of small, unsubsidized tankers is devoted entirely to a discussion of why they lacked standing. Citing past agency holdings as precedent, Marad first stated that its interpretation of the rule precludes standing for vessels under 100,-000 dwt. As justification for this interpretation, Marad referred to the relatively small part these tankers play in the Alaska-Panama trade. See Marad Opinion at 51-56, reprinted in J.A. at 72-77. The various comments and considerations raised by the owners of small, unsubsidized tankers do not appear anyplace in Marad’s evaluation of the waiver applications. Compare id. at 12-19, reprinted in J.A. at 33-40 (protests of Victory, Cove, and Sun) with id. at 51-56, reprinted in J.A. at 72-77 (Marad discussion of small vessels’ protests). The “standing” or right to “participate to some extent” of these small vessels, it thus appears, did not even figure as a “sometimes thing” in Marad’s ruling on the merits.
We need not tarry over the agency’s conflicting signals, however, because the regulation at issue, on straight, sensible reading, does accord standing to the small tankers as “competitors.” The regulation applies the 100,000 dwt limit to two categories of ships: first, to subsidized tankers eligible to apply for a waiver under the rule; and second, to unsubsidized tankers that qualify as “suitable” vessels for the trade. See 46 C.F.R. §§ 250.1, 250.2(h). “Suitable” vessels figure at two points in the regulation. The waiver applicant must aver that no “suitable” vessel is available to do the work for which the subsidized ship seeks a waiver. See id. at § 250.3(d). In addition, a suitable vessel that is available for such work and protests the waiver may automatically block the entry of a subsidized ship into the trade. See Brief for Seatrain et al. at 26-27.
Nothing in the regulation, however, limits protestors to “suitable” vessels. On the contrary, the regulation allows protests by any “competitor” and defines “competitor” to encompass unsubsidized vessels without reference to any size restriction. See 46 C.F.R. § 250.2(c). Thus, the appellants *948may protest because they fit within the regulation's definition of a “competitor,” but they may not automatically block a waiver because they do not qualify as “suitable” vessels.
III.
As protestors with standing, appellants have a right to have their comments heard and considered by the agency. Appellants’ comments covered a wide range. The most important objection appellants tendered, however, concerns an alleged indirect effect of the waivers on the segments of the Alaskan oil trade in which small unsubsidized tankers are primarily employed. Appellants complain of a “bumping” effect. They contend that when subsidized YLCCs are waived into the Alaska-Panama Canal segment of the trade, slightly smaller unsubsidized ships are “bumped” from that segment into the shorter segment of trade from Alaska to the West Coast. In turn, appellants say, vessels engaged in the Alaska-West Coast trade are bumped down into the Panama Canal-Gulf Coast and Panama Canal-East Coast segments of the trade, segments initially served by even smaller unsubsidized ships. Appellants claim that, as a result of this “bumping” process, the weight of the waivers is in fact felt, not by the large “suitable” vessels which can find work in another segment of the trade, but by the very small unsubsidized ships at the end of the line, ships that are ultimately “bumped” out of the market altogether. See Brief for Appellants at 33-34; Reply Brief at 4-12.
Appellants’ “bumping” argument raises a concern that Marad is statutorily required to consider. The Act is intended to protect the entire merchant marine, subsidized and unsubsidized, large and small. See Seatrain Shipbuilding Corp. v. Shell Oil Co., 444 U.S. 572, 574, 100 S.Ct. 800, 802, 63 L.Ed.2d 36 (1980) (describing objective of statutory scheme “to protect and support the United States’ shipping and shipbuilding industries”). The legislation indicates no solicitude for the interests of large, subsidized vessels that overrides consideration of the interests of small, unsubsidized ships. Indeed, to the extent that the Act expresses special concern for any vessels in the domestic trade, those vessels are the ones composing the unsubsidized fleet. See Atlantic Richfield Co. v. United States, 774 F.2d 1193, 1203 (D.C.Cir.1985) (“dual purposes of the Act” are “to protect the unsubsidized domestic fleet from displacement by the subsidized fleet, while still ensuring adequate domestic shipping capacity”).
Appellants, it bears emphasis, seek no trump card or veto power; they ask merely for consideration of their interests. See Reply Brief at 13 (appellants request “[a]n opinion compelling MarAd to consider the effect of temporary waivers on [their] segment of the [unsubsidized] fleet”). When Marad ignores their pleas, the agency shuts from its view a principal goal of the legislation: protection of the unsubsidized fleet.6 To the extent that Marad’s regulation, as interpreted by the agency, permits Marad to disregard appellants’ statutory interests, the regulation is substantively inconsistent with the Act.
Marad has thus far entirely avoided appellants’ “bumping” argument. The agency’s discussion of the unsuitability of these smaller vessels for the Alaska-Pan*949ama Canal trade, see Marad Opinion at 52-53, reprinted in J.A. at 73-76, leaves the “bumping” argument untouched.7 Appellants could admit that they play only a small role in that longest segment of the trade and still insist that waivers for the Alaska-Panama segment eventually impact on small carriers in other segments of the Alaskan trade. The very economic incentive to use larger ships, which Marad relies upon in its discussion of suitability, see id. at 52, reprinted in J.A. at 73, has been cited by appellants in support of their “bumping” argument. If trade participants operating mixed fleets know they can get waivers for subsidized YLCC’s, appellants maintain, such participants will shift their larger unsubsidized vessels to the other segments of the trade to make space for the VLCCs, for the larger the vessel they can use in each segment, the lower the cost will be. See Reply Brief for Appellants American Trading Transportation Co., Inc. et al. at 8-9 & n. 13.8
Marad’s regulation, we add, does not itself reflect any prior, general evaluation of the “bumping” effect that would obviate a need for further consideration in individual cases. Nothing in the language of the rule suggests that Marad has considered the matter and concluded that the entry of subsidized VLCCs into the Alaska-Panama trade has no impact on small, unsubsidized vessels in other segments of the Alaskan oil trade.9 The rule’s supplementary information and statement of purpose are similarly silent on this issue. See 42 Fed.Reg. 33035 (1977) (codified at 46 C.F.R. Part 250).
Nor does the regulation’s operation suggest that Marad has implicitly resolved this issue.10 If the regulation were in fact based on an unannounced determination that waivers had no impact on members of the unsubsidized fleet who were not engaged in the Alaska to Panama trade, then the veto power given to “suitable” *950vessels — which under this supposition are the only unsubsidized ships affected by waivers — would indeed be a sufficient safeguard of the unsubsidized fleet. In that case, the “dual purpose” of § 506 — to protect the unsubsidized fleet and to assure adequate tonnage, see supra at 948— would both be fulfilled whenever the regulation’s requirements were met. In short, had Marad implicitly determined that consents to temporary transfers have no impact on ships like appellants’, the regulation should have authorized Marad to grant waivers automatically so long as the applicant has arranged work for which no suitable vessel is available.
The regulation, however, does not operate in this self-executing manner. Marad has held that the regulation’s requirements set only a procedural minimum, see Marad Opinion at 43, reprinted in J.A. at 64; even after an applicant has demonstrated that the required conditions exist — that there is work to be done and no suitable vessel available to do it — Marad may deny the waiver if the agency finds that the requested entry permission is not necessary or appropriate to fulfill the purposes of the Act. In other words, the regulation, as interpreted by Marad, implicitly acknowledges that there may be statutory concerns informing Marad’s waiver decision that go beyond the availability of work and the unavailability of “suitable” vessels. The impact of the requested waiver on the remainder of the unsubsidized fleet is such a statutory concern. See supra at 948. Nothing in the structure or operation of the regulation, in sum, excuses Marad from considering this issue.11
Conclusion
Marad’s failure to address appellants' “bumping” argument brings the agency into conflict with its statutory mandate. To the extent that Marad’s interpretation of its regulation authorizes this disregard of appellants’ alleged interests, the regulation is inconsistent with the Act. Marad may, of course, address this issue either through rulemaking or adjudication and, once it has done so, the agency need not reassess its position in every subsequent proceeding in which the issue arises.12 Marad must, however, reach a decision — a decision based on a reasoned consideration of relevant evidence — before it can peremptorily dismiss the statutory interest appellants assert.13 We therefore *951vacate the district court’s judgment and remand the case to that court with instructions to return the matter to the agency for consideration of appellants’ indirect impact (“bumping”) arguments.
It is so ordered.
. The Act includes as part of the United States the "areas and installations in the Republic of Panama made available to the United States pursuant to the Panama Canal Treaty of 1977 [and] the agreements relating to and implementing that Treaty_” 46 U.S.C. § 1244(g). Trade between Alaska and the Panama Canal *945therefore ranks as domestic rather than foreign trade.
. As appellants point out, repayment of the construction subsidy decreases but does not eliminate the subsidized ships’ competitive advan- . tage. Subsidized ships working in the domestic trade must repay principal, but they bear no attendant carrying charge; they can therefore work at lower rates than the unsubsidized ships, which must pay interest on their borrowings for construction. The Supreme Court has recognized this continuing (time-value) advantage as a "considerable reason to restrict the extent to which subsidized vessels” are granted temporary waivers allowing them to "enter and exit the domestic market.” Seatrain Shipbuilding Corp. v. Shell Oil Co., 444 U.S. 572, 588 n. 30, 100 S.Ct. 800, 810 n. 30, 63 L.Ed.2d 36 (1980). Permanent waivers, which effectively transform a subsidized ship into an unsubsidized one, do not raise the same concerns; vessels granted permanent waivers must pay interest charges on their subsidies and are no longer able to alternate between the foreign fleet and the domestic fleet at will. See id. at 588-89 & n. 31, 100 S.Ct. at 810 & n. 31. But see diss. at 956 n. 13.
.The three ships were owned and operated by the following companies: the MARYLAND was owned by Boston VLCC Tankers, Inc. VI and chartered by Seatrain Lines, Inc.; the BROOKLYN was chartered by Archon Shipping, Inc. and American Petrofina, Inc.; the ARCO SPIRIT was owned by Arco Transportation Co. Marad granted the applications of the MARYLAND and the BROOKLYN and denied the application of the ARCO SPIRIT. The owners/operators of the successful vessels intervened as defendants in the district court and on appeal. See American Trading Transportation Co. v. United States, 610 F.Supp. 457, 459 (D.D.C.1985), reprinted in J.A. at 84.
. Marad dismissed the protests of the unsubsidized vessels over 100,000 dwt on the ground that they had failed to show that any of them would actually be available for work at the times for which the waivers were requested. See Marad Opinion at 48-50, reprinted in J.A. at 69-71.
. Appellants also raised claims concerning limitations on their opportunity to respond to comments by the applicants and surreptitious consideration by Marad of the agency's financial stake in the vitality of one of the VLCC owners/operators. See American Trading, 610 F.Supp. at 463-64, reprinted in J.A. at 93-95; *947Brief for Appellants at 48-57. The district court rejected both claims. See American Trading, 610 F.Supp. at 463-64, reprinted in J.A. at 93-95. Our disposition does not require us to reach these claims; nonetheless, in light of the curious circumstances surrounding the waivers at issue, see Brief for Appellants at 51-55, it is within our province to remind Marad that it may consider its financial interest in an applicant’s continuing vitality only if 1) it does so openly and honestly, and 2) it allows other parties an opportunity to comment on that consideration. See Independent United States Tanker Owners Committee v. Lewis, 690 F.2d 908, 930-31 (D.C.Cir.1982).
. Although the legislation is also intended to protect the subsidized fleet, Marad need not consider the impact of a denial of a waiver request on the subsidized ships that compete with the applicant. But see diss. at 956, n. 14. The Merchant Marine Act protects the subsidized fleet by providing it with subsidies; the Act protects the unsubsidized fleet by reserving for it the domestic trade. See diss. at 951 n. 1. The Act does not protect either fleet, however, from competition within its own ranks. Marad must consider the impact of waivers on the unsubsidized fleet — when properly raised — because waivers threaten the precise mechanism that Congress chose to use to protect that fleet: the restriction of domestic trade to unsubsidized U.S.-flag vessels. Marad need not consider the impact of a waiver denial on the competitors of the subsidized applicant because Congress had no intention of protecting subsidized ships from competition with each other.
. The dissent’s extended discussion of Marad’s reasoning, and its own revision thereof, see diss. at 953-55, effectively confirms that the agency nowhere considered the appellants' primary contention: that they are suffering an indirect effect in the other segments of the Alaska trade as a result of the temporary waivers.
The dissent, we note, relies most heavily, not on the agency’s actual reasoning, but dominantly on the dissent’s own assertion that ”[i]t follows ... as the night the day,” that the unsubsidized shippers will, in fact, suffer an indirect harm from the waivers. See diss. at 955. This admission — which Marad itself has never made — adds weight to our position. If it is inevitable that the unsubsidized shippers will be hurt, then it is incumbent upon Marad explicitly to acknowledge and address that point. Marad must consider the extent to which unsubsidized vessels will be disadvantaged and determine whether the benefit to be gained from the waivers justifies the injury to such vessels. We think such forthright consideration unavoidable if the agency is to carry out with fidelity its statutory charge to grant waivers only when necessary or appropriate to fulfill the purposes of the Act. We, of course, essay no instruction to Marad on the result it should reach after engaging in the requisite inquiry; we simply recall for the agency its duty not to ignore one of the primary concerns of the statutory scheme.
. Appellants’ arguments, as one of the inter-venors has demonstrated, are subject to serious factual challenges, see Brief for Archon et al. at 23-24. Marad may well conclude after full consideration that the facts do not support the appellants' contention of severe, albeit indirect, impact. But the agency may not rely upon the arguments of an intervenor to support its position in court when it has not itself considered and addressed the issue. Marad must reach and explain its own conclusions before a court can uphold the agency’s action. See Motor Vehicle Manufacturers Ass’n v. State Farm Mutual Automobile Ins. Co., 463 U.S. 29, 50, 103 S.Ct. 2856, 2870, 77 L.Ed.2d 443 (1983).
. The only provision in the regulation that could conceivably form the basis for Marad’s assertion that the regulation itself addresses appellants’ claims is the suitability provision. But, as already discussed, the fact that the small tankers are classified by the regulation as unsuitable for the Alaska-Panama trade does not bear on the question whether they may suffer an indirect impact from the waivers. See supra at 948-49.
. Even if it existed, such an "implicit” agency holding on the question of indirect impact would be invalid. Marad may not simply assume — without notice, comment, or explanation — that appellants’ statutory interests are not implicated when appellants claim that they are. Such an assumption based on no evidence would rank as arbitrary and capricious under the Administrative Procedure Act. See 5 U.S.C. § 706(2)(A) (1982).
. We need not reach the issue of the regulations’ procedural validity because we find that Marad’s application of its rule in this case — an application which blocked consideration of the alleged infringement of appellants' statutory interests — was substantively inconsistent with the Act. We note in passing, however, that we do not comprehend the basis for the district court’s lack of timeliness dismissal of the procedural claims. See American Trading, 610 F.Supp. at 461-62, reprinted in J.A. at 90-91. As we have noted, the language of the regulation gave appellants no notice that Marad would interpret it to block full consideration of their interests. See supra at 947. Had they challenged the rule at the time of promulgation, before the agency developed this interpretation, we would no doubt have found the challenge unripe for review because the harm appellants now claim they have in fact suffered would, at that time, have been only speculative. No time limit bars appellants from challenging a regulation that, they allege, is currently being used in a particular proceeding to harm them in a way they could not have anticipated at the time the rule was adopted.
. Contrary to the dissent’s suggestion, see diss. at 956, Marad need not make this assessment anew in every individual case. The appellants in this case present a general argument that waivers have an indirect impact on small unsubsidized vessels in the other segments of the Alaska trade. Marad may, when it examines this claim, find that the mechanics of the industry either preclude such an impact or limit it to an insignificant size. In subsequent proceedings, the agency would be free to reject any renewal of evidence on the generalized occurrence of such indirect injury. Protestants in later proceedings would, of course, retain the right to argue that their case involves special circumstances that make the application of the general rule inappropriate, but all rules are subject to that type of challenge.
. We do not ask the agency to institute any new procedures. But see diss. at 955-56. We merely insist that Marad consider protestants’ claims when those claims are properly raised through procedures adopted by the agency itself. Nor does our holding increase the cost to Marad of approving a waiver application. But *951see diss. at 955-956. The costs of approval and disapproval are identical and are set by the statute: the cost is always attentive agency consideration of all comments relevant to the purposes of the Act.