I received a thoughtful e-mail asking a good question. While I'll answer the question online, this is one where a picture can actually be very helpful. So I thought it might be best to include the answer here.
Question: In mark 6:45-52 is the story of Jesus walking on water and hopping into the boat with the disciples. the passage says that the disciples where in the MIDDLE of the lake. From my understanding of where the disciples started from and where they were going, they should not be in the MIDDLE of the lake. I would like for you to explain to me where I am in error geographically. So far the best I can do is to think that the MIDDLE refers to the disciples being halfway to their destination, but I really do not think that this is a correct interpretation either. This has been bugging me for a while.
Answer: Thanks for the question! I believe the answer can be found by understanding the fluid nature of the Greek word mesos. It can mean "in the middle," but it doesn't have to refer to the exact geographical center of an area. It can also mean "in the midst." According to The Complete Word Study Dictionary, the use of mesos with the preposition en (i.e., en mesos, which is the phrase used in Mark 6:47) usually means "in the midst" or "among." They illustrate this use with the following passages from the Gospels.
Matthew 10:16 "Behold, I send you out as sheep in the midst of wolves"
Matthew 14:6 "the daughter of Herodias danced before them" (lit. "in the midst of them")
Matthew 18:2 "called a child to Himself and set him before them" (lit. "in the midst of them")
Matthew 18:20 "where two or three have gathered together in My name, there I am in their midst"
Mark 9:36 "taking a child, He set him before them (lit. "in the midst of them"), and taking him in His arms, He said to them"
Luke 2:46 "they found Him in the temple, sitting in the midst of the teachers"
Luke 8:7 "And other seed fell among the thorns" (lit. "in the midst of the thorns")
Luke 10:3 "behold, I send you out as lambs in the midst of wolves"
Luke 22:27 "But I am among you (lit. "in the midst of you") as the one who serves"
Luke 22:55 "And after they had kindled a fire in the middle of the courtyard"
Luke 24:36 "He Himself stood in their midst"
John 8:3 "brought a woman caught in adultery, and having set her in the midst"
In these passages I think we can see that the normal understanding of the word is not "exact center" but "in the midst" in the sense of being surrounded by whatever it's in the midst of.
As we look at all the passages that record the incident with the disciples on the Sea of Galilee (Matthew 14; Mark 6; and John 6), I think they can be harmonized quite well. The feeding of the 5,000 took place on the NE side of the Sea of Galilee (to the east of Bethsaida), and the disciples were heading toward Capernaum, on the NW side of the lake (John 6:17). Jesus had advised them to take a route along the northern edge of the lake, which would have taken them by Bethsaida. But a strong wind was blowing against them, and it pushed them out into the center part of the lake. I say this for two reasons. First, John 6:19 says they had rowed "25 or 30 stadia." A stadia was 607 feet, so John said they had rowed somewhere between 2.9 and 3.4 miles. (Note that John is providing an approximation, saying the event happened around 3-3.5 miles from the point of origin. Second, Mark 6:53 tells us where they actually ended up. They landed at "Gennesaret." This is the Greek translation of the Hebrew word Kinneret, which is the Hebrew name for the Sea, the name of an OT city on the west side of the sea, and the name of the plain just to the south of that city. My point here is that the disciples ended up to the south and west of their original destination.
The photo at the top is a screen shot from Google Earth showing these locations. I've also drawn a line in the sea that is 3 miles long. The disciples were trying to row along the northern shore, but the wind was blowing them out into the lake. Rowing for three miles should have taken them almost to Capernaum, but they had been blown south so they were now "in the midst of the lake"…several miles off shore. After Jesus arrives on the scene, they finally made it to land, either at the site of Kinneret or on the Plain of Gennesaret.
Sorry to go into such detail, but I hope you find this explanation helpful!