However petitioners contend that the entry should be considered prima facie evidence that respondent himself requested his repatriation conformably with the rulings in Haverton Shipping Ltd. v. NLRCxv[15] and Abacast Shipping and Management Agency, Inc. v. NLRC.xvi[16] Indeed, Haverton says that a vessels log book is prima facie evidence of the facts stated therein as they are official entries made by a person in the performance of a duty required by law. However, this jurisprudential principle does not apply to win the case for petitioners. In Wallem Maritime Services, Inc. v. NLRCxvii[17] the Haverton ruling was not given unqualified application because the log book presented therein was a mere typewritten collation of excerpts from what could be the log book.xviii[18] The Court reasoned that since the log book was the only piece of evidence presented to prove just cause for the termination of respondent therein, the log book had to be duly identified and authenticated lest an injustice would result from a blind adoption of its contents which were but prima facie evidence of the incidents stated therein. In the instant case, the disputed entry in the Deck Log was neither authenticated nor supported by credible evidence. Although petitioners claim that Cajeras signed his Seamans Service Record Book to signify his conformity to the repatriation, the NLRC found the allegation to be actually untrue since no signature of private respondent appeared in the Record Book. Neither could the Medical Report prepared by Dr. Hoed be considered corroborative and conclusive evidence that private respondent was suffering from paranoia and other mental problems, supposedly just causes for his repatriation. Firstly, absolutely no evidence, not even an allegation, was offered to enlighten the NLRC or this Court as to Dr. Hoed's qualifications to diagnose mental illnesses. It is a matter of judicial notice that there are various specializations in medical science and that a general practitioner is not competent to diagnose any and all kinds of illnesses and diseases. Hence, the findings of doctors who are not proven experts are not binding on this Court.xix[19] Secondly, the Medical Report prepared by Dr. Hoed contained only a general statement that private respondent was suffering from paranoia and other mental problems without providing the details on how the diagnosis was arrived at or in what stage the illness was. If Dr. Hoed indeed competently examined private respondent then he would have been able to discuss at length the circumstances and precedents of his diagnosis. Petitioners cannot rely on the presumption of regularity in the performance of official duties to make the Medical Report acceptable because the presumption applies only to public officers from the highest to the lowest in the service of the Government, departments, bureaus, offices, and/or its political subdivisions,xx[20] which Dr. Wden Hoed was not shown to be. Furthermore, neither did petitioners prove that private respondent was incompetent or continuously incapacitated for the duties for which he was employed by reason of his alleged mental state. On the contrary his ability as Chief Cook Steward, up to the very moment of his repatriation, was rated Very Good in his Seamans Service Record Book as correctly observed by public respondent. Considering all the foregoing we cannot ascribe grave abuse of discretion on the part of the NLRC in ruling that petitioners failed to prove just cause for the termination of private respondent's overseas employment. Grave abuse of discretion is committed only when the judgment is rendered in a capricious, whimsical, arbitrary or despotic manner, which is not true in the present case.xxi[21]