By the end of World War II, German submarine designers had produced some astonishing weapons. Among the interesting were the Walter submarines, which could run submerged at high speed, using a turbine engine that didn't need external oxygen. One such boat reached a submerged speed of 24 knots in 1943, some 18 knots faster than previous U-Boats, and three knots faster than most convoy escorts. Plans were made to build several models of Walter boat, though none were in service before the war ended.
Some years ago a discussion of these boats led to speculation on what might have happened if one had been built and sent into combat. Such a boat would be very hard to detect, and nearly impossible to pin down and destroy. And what sort of man would command her? A senior commander, surely, but by late in the war what shape would he be in? U-Boats were, bar none, the most dangerous military assignments of World War II. Only one in four who sailed in them survived the war. So an experienced commander would be not only lucky, but also, more than likely, verging on what today we call a "burn out case."
And the sudden appearance of such a U-Boat, with the resulting disastrous effects on the convoy routes, would naturally call for a response. So we would also have a senior British escort commander, with a unique insight into his enemy after having been briefly a prisoner aboard his boat, now given command of a new killer group and charged with hunting him down.
These speculations resulted in "With Honour in Battle." A remarkable U-boat, with an advanced, but also dangerous, power plant; a no-longer-young commander, knowing what he's doing is going to be too late, yet duty bound to carry on the fight, and weighed down by the deaths of nearly everyone he has ever cared about. Not a "techno-thriller," but a traditional naval adventure novel, where the characters, and not the machines, drive the story. And, of course, one with plenty of action to keep things moving.