I realized several years later while serving aboard a nuclear submarine that this book was essentially about submarine warfare but set in space. The small attack ships were called climbers because they would climb into a fourth dimension to hide from the "battle cruisers" before and after they struck. Furthering the WWII era submarine theme, they could only stay hidden for so long, in this case, before overheating as they couldn't shed heat while in that dimension as I recall. Even referred to "Kool-aid" as bug-juice just like on subs. Also their unit anthem was a song called Outward Bound I think.
Googled the heck out of Outward Bound, and Climbers; you can probably guess the result. Thanks for any help.