I googled Fred. A. Plaisted and got a number of hits. Here are two:
Fred. A. Plaisted and M. Ahearn, two good amateur oarsmen, June 27, will row over the Charles River course, for $500 a side, and on the same day there will be a swimming match for $50 a side between J. A. Maines and Edward McAvoy; also a single-scull race for working boats, for $100 a side, between William Dixon and J. H. Carroll, over the same course; a match is to be made between the Macdonald brothers and T. C. Butler and John Landers, for double-sculls, but the time is not yet agreed on, though it will be some time in July, for $500 a side, and pulled over the same course. After the above race, Landers is ready to make a single-scull race against any one in New England for $500 a side and the championship of the States.
— The Boston Globe, 22 June 1874
The single-scull race rowed on Saturday morning on the Charles River was the closest contest for supremacy at the oar which Boston has seen for many a day. The match was between a stranger named Fred A. Plaisted of California and an amateur named Michael Ahern of the West End. Considerable interest has all along been manifested in the match, as it was now a bona fide affair, and was to call out a puller new to this section, and crowds of people were on hand to witness the race. Betting was quite lively, the odds of two to one being offered on the stranger. The course was from the judges' boat, off the Union Boat Club House, to and around a stake boat one mile up stream.
At 9 o'clock the men appeared. Ahern stripped to the waist, while Plaisted wore a red flannel shirt. The latter was much the larger of the two, weighing in his flannels about one hundred and sixty. Ahern was in excellent condition, weight about one hundred and forty.
Plaisted won the toss and inside position, giving Ahern the side farthest from the wall and more in the current. When the word was given, Ahern took the water first, and went away with half a length lead, pulling with a good clean stroke. Plaisted took matters very easy, but his stroke seemed not as promising a one as Ahern's, and it lacked in the finish, also in the dip. In the first half mile, Ahern had pulled out nearly four open lengths, and then he took still another, holding it to the stake. He turned in six minutes and thirty-two seconds, and had nearly straightened away when Plaisted turned. Both rounded in fine order, and when they began their return it was noticed that Plaisted took and left the water cleaner than on the first half, and seemed to attend more closely to his work. He still kept inside and Ahern the outside, going wide for the favor of the current, which, however, was not great. Plaisted slowly and steadily closed up the lead, although Ahern kept playing his sculls very steadily and strong. When within half a mile of the finish, they were about even, and then for a time it looked as if the red shirt was leading. Ahern made a spurt, and had his competitor so he could see his back, but he had pulled out a little too far, and in working in-shore Plaisted had the advantage. When within a dozen boat lengths of the judges, Plaisted put his all on the sculls, and came over the imaginary line the winner by little more than half a length. Ahern, being too far out, collided with the judges' boat, but did not injure his shell, and was fished out of the water, refreshed by his involuntary bath. He had pulled all there was in him. Plaisted had overmatched Ahern but a trifle, for he fell on getting out of his boat, had to be helped from his boat, and with assistance could hardly walk up the raft of the Union Club, where stimulants, etc., were administered. The time of this two-mile race was 15.36. Ahern was beaten [by] four seconds. Mr. William McDonald acted as referee, and the $200 was awarded to Plaisted. The excitement over the last half mile among the spectators was very great, and the friends of Ahern, defeated by so little, are ready to back their champion against the California man, within any space of time, and for any reasonable amount of money.
Aquatic Notes
It is understood that Fred E. Plaisted, who was so narrowly defeated [sic] by Ahern, the Boston amateur, in Saturday's scull race, at one time held the championship of California for single sculls.
— The Boston Globe, 29 June 1874