By this time (so also Good News Translation, Barclay) is literally “but … already” (New International Version). However, the function of the temporal phrase is to indicate that the boat had been moving to its present position, so that this event was taking place precisely at the moment that Jesus was alone on the mountain in prayer. New American Bible has “Meanwhile”; both Phillips and New Jerusalem Bible have “while … by now.”
There are languages where it is not normal to speak of the boat alone, but as “the boat with the disciples” or “the boat the disciples were in.”
Many furlongs distant from the land is expressed in more contemporary language by Good News Translation: “far out in the lake.” The Greek word rendered furlong by Revised Standard Version was about two hundred yards; consequently many furlongs would intimate that the disciples had gone some distance into the lake, which measures about four and a half miles across. Jerusalem Bible is similar to Good News Bible: “far out on the lake.” But, as RSV’s footnote indicates, there is an alternative textual choice. Some manuscripts have “in the middle of the lake” in place of many furlongs distant from the land. TC-GNT believes that this alternative reading was made by some scribe who attempted to make Matthew’s text read similar to Mark (6.47). In either case, neither reading gives a specific measurement; both merely state that the boat was now some distance from the shore, and therefore any phrase that conveys this information will be faithful to the intent of the text. Barclay translates “a good distance from land.”
Beaten (Good News Translation “tossed about”) is also a participle, made from the same verb as the one translated “in … distress” in 8.6 (see comments there). Scholars are in almost unanimous agreement that in Matthew it is the boat, rather than the disciples (as in Mark 6.48), which is in danger from the waves. This alteration is in keeping with Matthew’s theology, in which the boat has become an image of the church. Consequently beaten by the waves may have to be made into an active sentence such as “the waves were beating against the boat.”
For the wind was against them is translated “because the wind was blowing against it” by Good News Translation. The Greek text has no expressed object of the adjective represented by against in Revised Standard Version, but if an object must be expressed, then “it” (the boat) is preferable to them (the disciples), since the boat is the expressly mentioned subject of the sentence. New Jerusalem Bible skirts the problem (“for there was a head-wind”), while New English Bible translates beaten by the waves; for the wind was against them by the abbreviated form “battling with a head-wind and a rough sea.” For the wind was against them, translators can choose the perspective of the wind, as in “for the wind was blowing against them,” or that of the boat, as in “for they were going straight into the wind.”
Some translators will find it more natural to restructure the verse somewhat: “By this time, the boat (with the disciples) was far from the shore. It was going into the wind, and the waves were beating against it.”
Quoted with permission from Newman, Barclay M. and Stine, Philip C. A Handbook on the Gospel of Matthew. (UBS Handbook Series). New York: UBS, 1988. For this and other handbooks for translators see here .