OPINION
This cause arises out of a collision of motor boats being operated for pleasure on Navajo Lake or Reservoir on July 3, 1967.
Although plaintiff and plaintiff in intervention rely upon two points for reversal, both points relate to the single question of whether Navajo Lake is part of the navigable waters of the United States. We hold it is, and that the trial court erred in finding and concluding otherwise. Thus, we decide only the first point, and briefly consider the question of damages, since the case must be remanded to the trial court for the purpose of awarding damages to plaintiff and plaintiff in intervention.
Plaintiff was the owner and operator of one of the boats at the time of the collision. The plaintiff in intervention was. his insurer and intervened to recover the amounts it paid to plaintiff for damages to his boat and his medical expenses. Defendant was the owner and operator of the-other boat at the time of the collision.
The trial court found and concluded that the collision occurred as the proximate result of the negligence of both plaintiff and defendant. Neither this finding nor this, conclusion is challenged, and plaintiff and plaintiff in intervention concede they are-barred from recovery by plaintiff’s contributory negligence, if the New Mexico law of negligence is applicable.
It is agreed that if Navajo Lake is a. part of the navigable waters of the United States, then maritime law is applicable and' damages are recoverable thereunder by plaintiff and plaintiff in intervention. Authority for the applicability of maritime law to navigable waters of the United States is found in Art. III, § 2 of the Constitution of the United States, wherein it is provided: “The judicial Power shall extend to-all Cases * * * of admiralty and maritime Jurisdiction; * * *”
The applicability of maritime law to-claims arising on navigable waters of the United States is discussed in Intagliata v. Shipowners & Merchants Towboat Co., 26 Cal.2d 365, 159 P.2d 1 (1945), wherein it is stated:
“Plaintiff’s claim arises from a collision on navigable waters of the United States and thus involves a maritime cause of action [authority omitted], which in a federal court sitting as a court of admiralty would be determined under federal maritime law. [authorities omitted] The federal maritime law provides for equal division of damages, if both parties were at fault, even though there was a disparity in fault, [authorities omitted] Jurisdiction of the state court to try the action is based on section 24(3) of the *158Judicial Code, 28 U.S.C.A. § 41(3), which in ‘all civil causes of admiralty and maritime jurisdiction’ saves to suitors ‘the right of a common-law remedy where the common law is competent to give it.’ The remedy afforded in the state court may be invoked to secure such rights 'as readily admit of assertion and enforcement in ■actions in personam according to the course of the common law.’ [authorities ■omitted] Plaintiff’s action is in person-am to recover damages for tort and is ‘one of the most familiar of the common-law remedies.’ [authority omitted] ‘That there always has been a remedy at ■common law for damages by collision at .sea cannot be denied.’ [authority ■omitted] Since contributory negligence generally precludes a plaintiff from recovering damages at common law, defendant contends that the doctrine of contributory negligence is part of the ■common-law remedy and is therefore binding on a state court in a maritime ■cause as a limitation of the court’s juris■diction.
“ * * *
“It is now settled that ‘The general .rules of the maritime law apply whether the proceeding be instituted in an admiralty or common law court,’ [authorities ■omitted] and that the state courts must ■preserve all substantial admiralty rights of the litigants, [authorities omitted] A state court having the same jurisdiction over a case that a federal court would have if the suit had been brought there, must determine the rights of the parties under the maritime law as a ‘system of law coextensive with, and operating uniformly in, the whole country.’ [authorities omitted] State law is inapplicable to a maritime cause ‘if it contravenes the essential purpose expressed by an act of Congress, or works material prejudice to the characteristic features of the general •maritime law, or interferes with the proper harmony and uniformity of that law in its international and interstate relations.’ [authorities omitted] * * * ‘Any rule of assumption of risk in admiralty, whatever its scope, must be applied in conjunction with the established admiralty doctrine of comparative negligence and in harmony with it. Under that doctrine contributory negligence, however gross, is not a bar to recovery but only mitigates damages.’ [authorities omitted] Any doubt as to whether the foregoing cases or Belden v. Chase governs maritime causes in the state courts is dispelled by the Supreme Court’s declaration in Garrett v. Moore-McCormack Co., supra, 317 U.S. [239] pages 244, 245, 63 S.Ct. [246] at page 250, 87 L.Ed. 239, that: ‘In many other cases this Court has declared the necessary dominance of admiralty principles in actions in vindication of rights arising from admiralty law, Belden v. Chase, 150 U.S. 674, 14 S.Ct. 264, 37 L.Ed. 1218, an 1893 decision which respondent relies upon as establishing a contrary rule, has never been thus considered in any of the later cases cited.’ « * * *
“There can be no doubt that the division-of-damages rule in maritime collision cases involving the fault of both parties is as binding on the state courts as the federal rule as to burden of proof with respect to the validity of releases in suits by seamen for maintenance and cure. The right of a plaintiff to a division of damages in a maritime collision case involving the fault of both parties is a substantial right deeply rooted in admiralty, inherent in his cause of action, and such a part of the substance of his claim that it ‘cannot be considered a mere incident of a form of procedure.’ It is indeed an essential characteristic feature of the substantive law of admiralty. The very basis of the plaintiff’s cause of action, which is unquestionably a maritime cause of action, would be destroyed if recovery were denied because of his contributory negligence, for it is only under admiralty law that he has any claim for damages arising from a maritime collision caused by the fault of both parties. If the state court should apply state law rather than admiralty law ‘the remedy *159afforded by the state would not enforce, but would actually deny, federal rights which Congress, by providing alternative remedies, intended to make not less, but more secure.’ [authorities omitted] That the United States Supreme Court regards the plaintiff’s right in such a case as a substantial admiralty right clearly appears not only from its abandonment of Belden v. Chase, but from its references in the Garrett case to state doctrines of contributory negligence and assumption of risk as doctrines that must give way to admiralty principles in actions at law on maritime torts. * * *
« %
“Federal law governs not only the consequences of the fault of the parties but the question whether their vessels were operated in compliance with the rules governing navigation on navigable waters of the United States. The Federal Inland Rules of Navigation, 30 Stats. 96-102, 33 U.S.C.A. §§ 171-231, are controlling except as they permit the application of special local law. * * * ”
See also, generally, as to what are navigable waters of the United States and the measure of recoverable damages under maritime law for damages and injuries sustained thereon, Guinn, An Analysis of Navigable Waters of the United States, 18 Baylor Law Review 559 (1966); Sanders, Admiralty in the Ozarks, 23 Ark.Law Review 96 (1969), (Reprinted in 33 ATL L.J. (1970)).
The question of navigability is one of fact. Arizona v. California, 283 U.S. 423, 51 S.Ct. 522, 75 L.Ed. 1154 (1931); United States v. Utah, 283 U.S. 64, 51 S.Ct. 438, 75 L.Ed. 844 (1931); The Daniel Ball, 77 U.S. (10 Wall.) 557, 19 L.Ed. 999 (1870); United States v. Rio Grande Dam & Irr. Co., 9 N.M. 292, 51 P. 674 (1898). However, it is a fact of which a court may take judicial notice, at least insofar as the waters are within its jurisdiction. Arizona v. California, supra; United States v. Dam & Irr. Co., supra.
The evidence adduced at the trial relating to the question of navigability is undisputed. The trial court found:
“On the date of the accident, Navajo Lake was a body of water lying within two states, New Mexico and Colorado, and capable of being traveled upon by small boats between the two states.”
This finding is not attacked and is unquestionably supported by the evidence. The evidence as to the size of the boats which travel upon this Lake was that they range in size from small ski boats to house boats 52 feet in length, and there was testimony that “any boat you can put in the water” can be operated on the Lake between New Mexico and Colorado.
The collision in question was investigated by the United States Coast Guard, consistent with its duties relative to waters subject to the jurisdiction of the United States. 33 C.F.R. § 2.05-1 (Rev. as of January 1, 1970). Waters subject to the jurisdiction of the United States, for the purpose of enforcement of regulations administered by the Coast Guard, means the navigable waters of the United States, 33 C.F.R. § 2.10-10, supra. Navajo Reservoir has been determined by the Commandant, United States Coast Guard, to be a part of the navigable waters of the United States. 33 C.F.R. §§ 2.26-1 and 2.53-1, supra. This determination is expressed in 34 F.R. 2203, February 14, 1969, as follows:
“A determination has been made that the Navajo Reservoir crosses the border between Colorado and New Mexico and is part of the navigable waters of the United States because it permits navigation or travel between two States, and this interpretation is in 33 CFR 2.26-1 and 2.53-1. The main body of the reservoir extends 35 miles within New Mexico along the San Juan River. After crossing the Colorado-New Mexico State line, the reservoir extends about 7 miles into Colorado.”
Although this determination by the Commandant, United States Coast Guard, is not conclusive of the issue of navigabili*160ty, it is relevant evidence thereon. See Lutesville Sand & Gravel Co. v. McLaughlin, 181 Ark. 574, 26 S.W.2d 892 (1930). As already stated, we agree with this determination, and disagree with the finding and conclusion of the trial court that:
“Navajo Lake is not used nor susceptible of use as a body of water in its ordinary condition over which trade and travel may be conducted in the customary modes of trade and travel on water.”
And, therefore, is “not navigable waters of the United States.”
In The Daniel Ball, supra, the Supreme Court announced the following test:
“ * * * Those rivers must be regarded as public navigable rivers in law which are navigable in fact. And they are navigable in fact when they are used, or are susceptible of being used, in their ordinary condition, as highways for commerce, over which trade and travel are or may be conducted in the customary modes of trade and travel on water. And they constitute navigable waters of the United States within the meaning of the Acts of Congress, in contradistinction from the navigable waters of the States, when they form in their ordinary condition by themselves, or by uniting with other waters, a continued highway over which commerce is or may be carried on with other States or foreign countries in the customary modes in which such commerce is conducted by water.”
Navigable waters of the United States may include artificial [or man-made] waterways, as well as those which are natural. Ex Parte Boyer, 109 U.S. 629, 3 S.Ct. 434, 27 L.Ed. 1056 (1883).
The capability or susceptibility for use by the public as a highway for trade .and travel is the true criterion by which to ■determine the navigability of waters. Economy Light & Power Co. v. United States, 256 U.S. 113, 41 S.Ct. 409, 65 L.Ed. 847 (1921); The Montello, 87 U.S. (20 Wall.) 430, 22 L.Ed. 391 (1874); The Daniel Ball, supra; Madole v. Johnson, 241 F.Supp. 379 (W.D.La.1965). This criterion is applicable if the capability can be accomplished by making reasonable improvements. United States v. Appalachian Electric Power Co., 311 U.S. 377, 61 S.Ct. 291, 85 L.Ed. 243 (1940); Economy Light & Power Co. v. United States, supra; Pennsylvania Water & P. Co. v. Federal Power Com’n., 74 App.D.C. 351, 123 F.2d 155 (1941).
The type of craft used in accomplishing trade and travel over the waters is of no particular significance. Arizona v. California supra; The Montello, supra; The Lucky Lindy, 76 F.2d 561 (5th Cir. 1935); Hahn v. Ross Island Sand & Gravel Co., 214 Or. 1, 320 P.2d 668 (1958), rev’d. on other grounds. 358 U.S. 272, 79 S.Ct. 266, 3 L.Ed.2d 292 (1958).
Applying the capability, or susceptibility, test to the waters of Navajo Lake on the date of the accident, we are of the opinion that these waters were navigable waters of the United States, and that the trial court should have awarded plaintiff and plaintiff in intervention damages consistent with the rules applicable in maritime collision cases.
The judgment is reversed and the cause remanded to the trial court for the purposes of determining and awarding plaintiff and plaintiff in intervention the damages to which they are entitled.
It is so ordered.
HENDLEY, J., concurs.
SPIESS, C. J., dissents.