Okay but are dolphins THAT smart?
Within the Trek universe, it is a canonical fact that cetaceans (in the person of humpback whales) are sapient beings. We're talking about a work of fiction. Dolphins can be as smart as the story needs them to be.
the ocean enviroment and lack of opposable thumbs make for some pretty benign brain challenges.
Hardly. The ocean is a much harsher and more challenging environment for an air-breathing mammal than the land is. If anything, there's a strong incentive to evolve intelligence as a means of dealing with those challenges, which is why dolphins are so smart and so social (since cooperation helps).
Even for animals that evolved there, there's nothing benign about the ocean. It's a complex, dangerous, often forbidding environment. If it were easier to live in the ocean than on land, life never would've had an incentive to evolve to live on land in the first place.
And lack of opposable thumbs is only relevant to technology, not intelligence. We conflate the two because we're a tool-using species, but that's just egocentrism. And in fact
dolphins are tool-users insofar as they're able to be.
I know dolphins are highly intelligent as far as vs other animals. but would a dolphin even know what a nav. computer was
Would Isaac Newton have even known what a nav computer was? No. But that doesn't mean he lacked intelligence, only a cultural context. Don't confuse knowledge with intelligence.
much less how to navigate in space? sure they can navigate in the ocean because there is gravity to tell them which way is down.
Uhh, are you forgetting that humans live in gravity too? We have to adjust our way of thinking to navigate in space. Dolphins would have less of an adjustment to make, because they're used to moving -- and thinking -- in three dimensions.
And gravity is of limited relevance in the ocean, since buoyancy largely cancels it out.
I would also take a leap here and say that you cant teach a dolphin the complex math required for the position you describe them having aboard the ship. and BTW, I'm not dissing dolphins or whales either, I happen to think they are wonderful animals and yes they seem very smart, but not THAT smart.
In some respects, dolphins are probably smarter than we are, although that's a crude way of putting it. We're different species with different evolutionary needs, so our intelligence has specialized in different directions.
http://serendip.brynmawr.edu/bb/neuro/neuro98/202s98-paper3/Ball3.html
By many of the physical methods of comparing intelligence, such as measuring the brain size to body size ratio, cetacean surpass non-human primates and even rival human beings. For example dolphins have a cerebral cortex which is about 40% larger a human being's. Their cortex is also stratified in much the same way as a humans(1). The frontal lobe of dolphins is also developed to a level comparable to humans. In addition the parietal lobe of dolphins which "makes sense of the senses" is larger than the human parietal and frontal lobes combined (1). The similarities do not end there, most cetaceans have large and well developed temporal lobes which contain sections equivalent to Broca's and Wernicke's areas in humans (1).
Another major difference between primate and cetacean brains is that the primate brain favors the motor cortex, while "the cetaceans greatly favor the sensory region (and are not very balanced at all between the two)" (1). In the final measure of brain complexity, neural density dolphins also measure up quite favorable to humans. In certain areas of the brain concerned with "emotional control, objectivity, reality orientation, humor, logically consistent abstract thought and higher creativity" dolphins have an higher ratio of neural density(1). This seems to be correlated with dolphins ability to maintain a healthy emotional state while in captivity; humans in analogous situations often don't fair as well emotionally.
To clarify, the frontal lobe is responsible for foresight, planning, decision-making, and social skills, and Broca's and Wernicke's areas are responsible for language.