This novel was probably written in the 1960's or 70's.
I recall the book cover had a man floating possibly in a raft on a red ocean and that it may involve time travel.
It also may have been the first book in a series.
Possibly about alternate futures the main character was more like an anthropologist( or archaeologist). The main character name possibly started with a "Q" (but its not "Q" from star trek) and may have been religious possibly Christian?
The main character ends up in an asylum.
I believe it was on Earth. Don't believe space travel was involved but on the book cover he may have been wearing a space suit.
Read the book back in the 90's and would like to re-read apologies for the vagueness.
- "The Godhead Trilogy" - James Morrow. Which has the two-mile-long corpse of God found floating at sea
- "Out of the Silent Planet" or its sequel "Perelandra" - C. S. Lewis
- "Interstellar Pig" - William Sleator. Which mentions "At sea, the Captain rescued a man floating in the ocean..."
- "Raft" - Stephen Baxter
- ''Worlds Apart (The Outer Limits)''
The following image is similar to what I remember on book cover (apart from the missing man of course)