Thе plaintiff, Marine Contractors Co., Inc. (Marine), seeks to enjoin the defendant, Thomas F. Hurley (Hurley), from competing with Marine in the business of marine specialist until March 31, 1976, within 100 miles of Boston, in accordance with a written agreement executed by the parties on April 1, 1971. Hurley appeals from a final decree granting Marine the injunctive relief sought.
The cаse was referred to a master, who conducted a hearing and submitted a report. On objection by Hurley to the report the case was recommitted to the master for summaries of certain portions of the evidence and for the inclusion in the report of a copy of the “Employee Retirement Plan and Trust.” After the inclusion of this evidence, *282 a second motion by Hurley to recommit the case to the master was denied. The judge confirmed the master’s report and entered a final decree as stated above, from which Hurley appeals. 1 There was no error.
We are bound by the master’s subsidiary findings of fact unless they are plainly wrong or mutually inconsistent, and we must determine only whether the final decree is supported by those facts found by the master and proper inferences therefrom.
Rose
v.
Hornsey,
We summarize the facts as found by the master. Since 1946, Marine has been engaged in the business of performing various specialized types of marine repair work, principally in the greater Boston area but as far awáy as Newport, Rhode Island, and Portland, Maine (each of which is within approximately 100 miles of Boston). Marine is one of a very few companies in the greater Boston area which engages primarily in such specialized repair work, although there are shipyards which compete for such work. Marine conducts its business by retaining only two or three permanent supervisors and by hiring crews of рart time workers as necessary for particular jobs. It relies on the ability of its supervisors to assemble workers with the particular skills which are needed for each job.
In 1958, Marine created an “Employee Retirement Plan and Trust” (the trust) for the benefit of its permanent employees. The sole trustee of the trust, Norman C. Thomas (Thomas), is also the president, treasurer, sole stockholder and a director of Marine. The trust agreement provides for annual contributions by Marine to the trust based on the company’s net income. All questions con- *283 ceming construction of the trust agreement, including those involving the powers and duties of the trustee, are to be decided by an administrative committee aрpointed by Marine. Funds accumulated under the trust accrue solely to the benefit of the participants, and can never revert to or be used for the benefit of Marine. As to distribution of benefits, the trust agreement provides in relevant part that when a participant leaves the employ of the company for reasons other than disability оr retirement at age sixty-five, then an amount equal to his vested share of the trust is required to be segregated into a separate savings account and held by the trustee for a five-year period. Only after the expiration of the five-year period may the trustee distribute those benefits (plus accumulated interest) to the participant. The purpose of the waiting period, as stated in the trust agreement, is to “encourage all employees to become and remain Participants in the... [trust].”
Hurley was a permanent employee of Marine from 1963 until April 1, 1971. He was the general superintendent of the business, and his duties included estimating and preparing bids, in addition to the supervision of ongoing work. As a rеsult of this employment Hurley became skilled in marine contracting both as a field supervisor and as an estimator and bidder. As a permanent employee Hurley was a participant in the trust, and by 1971 his vested share amounted to approximately $12,000. Sometime in March, 1971, Hurley notified Thomas of his plan to leave Marine’s employ as of April 1 in order to rеturn to his hometown of Stewartstown, New Hampshire. Thomas offered to make immediate payment to Hurley of his vested share of the trust in return for Hurley’s promise not to compete with Marine. Hurley agreed to this proposal. On April 1, Hurley and Marine (represented by Thomas) signed an “Agreement Not to Compete” in which Hurley, “in consideration of ONE DOLLAR ($1.00) and other good and valuable consideration,” promised not to compete with Marine, directly or indirectly, within 100 miles of Boston for five years. On the same date Hurley received the full amount of his share in the trust.
*284 Starting in August, 1971, Hurley began to perform marine work similar to the work of Marine. The jobs he performed were within 100 miles of Boston and at least some were performеd for customers known by Hurley to be customers of Marine. During this time counsel for Marine put Hurley on notice that he was violating the agreement not to compete. Hurley responded that he did not intend to comply with the terms of that agreement. In January, 1972, Hurley formed his own corporation to undertake the work which he had been doing as an individual. By that time the other two key supervisory employees who had been working for Marine as of April 1, 1971, had quit Marine and were working for Hurley. Owing to the loss of the services of Hurley and other key employees, Marine was unable to bid on or accept much work until April, 1972. Between August, 1971, and June 5, 1972 (the date on which the hearing before the master began), Hurley earned more thаt $24,000 from business done in violation of the agreement not to compete.
Marine filed its suit in September, 1971, and the injunction issued on June 5, 1973. By the terms of the injunction Hurley is barred until March 31, 1976, from engaging in the business of general maritime specialist, within 100 miles of Boston, either individually, as a member of a firm, or as a stockholder in a corporation, or a certificate hоlder in a business trust.
Although Hurley urges several grounds for vacating the injunction, his principal arguments are two: first, that there was no sufficient consideration to support his promise not to compete; and second, that his agreement with Marine constitutes an “unreasonable restraint of trade” as defined in the Restatement: Contracts, § 515 (1932). We disagree for the reasons stated below, and we hold that Hurley was properly enjoined from violating the terms of his agreement not to compete.
We consider first the question of consideration. The master found that the requirement of consideration was satisfied in two respects. First, because the agreement was, *285 in legal effect, a sealed instrument, 2 no consideration was necessary to make it a binding contract. Second, the acceleration by five years of the payment to Hurley of his $12,074.64 trust share amounted to consideration in fact.
As to the effect of a sealed instrument, Hurley concedes that the rule at law is that consideration is conclusively presumed for a promise under seal.
Kaplan
v.
Suher,
Apart from the seal we hold that the five-year acceleration of the trust benefit payment to Hurley was sufficient consideration to support specific performance of his prom
*286
ise not to compete. The requirement of consideration is. satisfied if there is either a benefit to the promisor or a detriment to the promisee. Williston, Contracts (3d ed.) § 102 (1957). See
Cottage St. Methodist Episcopal Church
v.
Kendall,
*287
Hurley’s second principal argument is that his agreement not to compete with Marine amounts to an unreasonable restraint of trade (Restatement: Contracts, § 515 [1932]
5
), and thus should not be enforced in equity. While it is true that agreements not to compete will be enforced only in so far as they are reasonable,
All Stainless, Inc.
v.
Colby,
In the first place, Hurley argues that, since his promise was not made until the termination of his employment with Marine, the agreement was unreasonable because not “ancillary” to his employment with Marine. Restatement: Contracts, § 515 (e) (1932). This argument misconstrues, we think, the purpose underlying the Restatement rule. Employee covenants not to compete generally are enforceable only to the extent that they are necessary to protect the legitimate business interests of the employer.
Novelty Bias Binding Co.
v.
Shevrin, supra,
at 716. Such legitimate business interests might include trade secrets, other confidential information, or, particularly relevant here, the good will the employer has acquired through dealings with his customеrs. See
All Stainless, Inc.
v.
Colby, supra,
at 779-780. Protection of the employer from ordinary corn-
*288
petition, however, is not a legitimate business interest, and a covenant not to compete designed solely for that purpose will not be enforced.
Richmond Bros. Inc.
v.
Westinghouse Bdcst. Co. Inc.
We may more quickly dispose of Hurley’s other two arguments based on § 515 of the Restatement. First, there is nothing in the master’s findings which would require a conclusion that the noncompetition agreement between
*289
Hurley and Marine would tend to create a monopoly (§ 515 [c]). The master found that Marine was “one of one or two companies” performing its type of specialized marine repair work in the Boston area, and that it received competition from shipyards in the area. Second, Hurley argues that the agreement imposes an “undue hardship” (§ 515 [b]) by barring him from earning his living in the marine contracting business, the business he knows best. The consequence of every covenant not to compete, however, is that the covenantor is deprived of a possible means of earning his living, within a defined area and for a limited time. That fact alone does not make such covenants unenforceable. Hurley has not established any extraordinary hardship which would be caused him by the enforcement of his promise not to compete. He may engage in any work other than marine repair work. Until April, 1976, if he wishes to perform marine repair work he may do so anywhere other than within 100 miles of Boston. Hurley freely entered into the agreement not to compete, see
New England Tree Expert Co. Inc.
v.
Russell,
Finally, although Hurley did not expressly argue the points, we believe the master’s finding that Hurley’s agreement not to compete with Marine was reasonable in time and space was warranted. The geographical scope of the agreement coincides with the area in which Marine performs almost all of its work, and thus is precisely drawn to protect Marine’s good will. See
Boston & Suburban Laundry Co.
v.
O’Reilly,
Interlocutory and final decrees affirmed.
Notes
Hurley also appealed from the denial of his motion to recommit the case for a second time to the master for a more accurate summary of the evidence and from the interlocutory decree confirming the master’s report. We need not consider these issues, however, because Hurley did not argue them in his brief. S.J.C. Rule 1:13,
The agreement contained a recitation that the parties thereto have “set their hands and seals.” This language is sufficient to give the agreement the effect of a sealed instrument. G.L. c.4, § 9A.
We should not be taken to imply that the seal would of itself render a purely gratuitous promise specifically enforceable.
Hurley also argues against specific enforcement of his promise on the ground that acceleration by the trustee of the benefit payment constituted a breach of the trustee’s fiduciary duty in that it was done for a purpose (i.e., to induce the promise not to compete) that was not in the best interests of the participant (i.e., Hurley). If there was a breach of fiduciary duty, a question we do not decide, Hurley clearly was aware of it and benefited by it. Thus he cannot complain. “If a beneficiary consents to an act by the trustee which would constitute a breach of
*287
trust toward the beneficiary, the benefiсiary cannot hold the trustee liable for the consequences of the trustee’s acts ‘if the beneficiary was sui juris and had full knowledge of all relevant facts and of his legal rights and if his consent was not induced by any improper conduct of the trustee.’ ”
Reynolds
v.
Remick,
Those portions of § 515 relied on by Hurley are: “A restraint of trade is unreasonable, in the absence of statutory authorization or dominant social or economic justification, if it...
(b) imposes undue hardship upon the person restricted, or
(c) tends to create, or has for its purpose to create, a monopoly...
(e) is based on a promise to refrain from competition and is not ancillary either to a contract for the transfer of goodwill or other subject of property or to an existing employment or contract of employment.”
