In most situations in life "being in the same boat" means that two or more people are facing the same challenge together. In dragonboat paddling, 22 people literally are "in the same boat". It should be a simple proposition, 22 people of different physical size, offering different skills, trying to move a boat down the water faster than the other groups of 22. Sometimes though, we make it complicated. This happens when people try to assign more or less value to their contribution in the boat. I don't know why people do this, I suspect the reason is that successful people in general like to be measured, and also because invariably crew selection is based on some sort of ranking of individual skills.
There really are not a lot of ways we can differeniate ourselves in a dragon boat, so people invariably use their position in the boat to measure contribution. This happens most often with crews that are just beginning to become competitive. In general they have learned to assign more value to positions nearer the front, as opposed to those in the back, because as the crew matured new people were moved to the back to learn and not interfere with more experienced paddlers in the front. The problem occurs once no one is a beginner, and the coach aligns sizes and skills to positions so as to optimize boat speed. Initially, the coach will encounter resistance from paddlers who think the coach is valuing them less since they are now being put in the back where "the new people" used to be.
This cannot be further from the truth. Ask any established coach, where, all things being equal, their best athletes are and they will say "in the back". Look at the boat this way - the front 3 on each side set tempo and "pull" the boat because the water isn't stirred up and more of the physical structure of the boat is behind them. The back 3 on each side "push the boat" because most of the physical structure of the boat is ahead of them. This is more difficult because the water is "stirred up" and moving, so the back 3 must have the skill and the athletic ability to "push" the boat and affect boat speed by generating effective paddle speed and connection in moving water. The middle 4 are generally larger paddlers (because the boat is wider) and are usually physically stronger, but they do not need the skill to set tempo in dead water or to generate paddle connection in fast moving water to the degree that the front 6 or back 6 do. If anything, the more skilled "engines" would be in seats 6,7 and the better "tempo" paddlers would be in 4, 5 - but alot of times balancing the boat bow/stern overrides those considerations.
So where you are in the boat is going to depend on your height, weight, temperment, skill, ability to set tempo, ability to find water connection, and by the person's ability to motivate people/ be motivated by people around you. Don't make the mistake of trying to assign "value" to your position. A lot of dragon boat races are decided by inches, every position is important, and the ability of the coach to match skill sets to the correct position is vital.
Or, put another way, as one of my teammates on the Canadian dragon boat team once told me, "I have no ego when it comes to dragon boat. None. I just want my boat to come first and I want to be in it." Which leads to crew selection, which is a topic for another day.