I asked a question at Quora about increasing mass as one approaches to light speed and got numerous answers saying that it doesn’t, yet other have written about concatenated effects of gravity acting to increase mass as one nears light speed. I believe it does. It is supposed to become infinite at light speed. Others say it doesn’t and one may just pass write on through with no problem. If it does increase toward light speed I would think a comparatively trivial gravitational field aboard the ship would be obliterated as the mass increased opposite to the direction of travel to infinity.
There may be a few reasons that apparent mass could increase to infinity- that is various fields such as the Higgs, as well as gravity, might be more localized, and passing through them too quickly could increase the forces acting upon the mass of the ship. Since gravity itself travels at the speed of light, it is hard to say what would happen if one went faster…something though one might guess.
Because all of the forces that hold mass together- strong, electro-weak, gravity etc. exist within a certain space-time circumstance it could be that some of those that hold the ship together would fail making the mass transition destructively. Maybe all of the particle fields act at the speed of light.
Others have asked the question- here are some replies… https://www.quora.com/Is-it-possible-for-human-to-survive-if-they-travel-at-the-speed-of-light
Someone pointed out that energy is converted into mass within criteria of general relativity nearing light speed. Maybe people confuse general and special theory paradigmata.