The Price of Admiralty.

The Price of Admiralty. John Keegan. Viking, $21.95. At 4:00 p.m. on May 31, 1916, during the Battle of Jutland, one of the main gun turrets of the British battlecruiser Lion was hit by a 12-inch German shell. For the unfortunates inside, it was as if their world had been fired by lightning.

The gun-house crew perished instantly; one, as he died, involuntarily switched on the loading hoist and sent burning cordite into the turret's depths. Fire raced down towards the magazines. Only an order from the dying turret officer that the doors be shut and the magazines flooded saved the ship. Lion was thus luckier than its sister, Invincible, which blew into halves when one of its gun turrets was hit shortly thereafter. Out of Invincible's 1,000-man crew, only six survived.

As the British military author John Keegan points out in his well-reasoned new book, The Price of Admiralty, such damage and death didn't have to happen. At the time of the Battle of Jutland, all Britain's capital ships had the same flaw: insufficient "antiflash" doors for preventing fire from racing through turrets and magazines. Keegan points out that the previously installed protective devices had been removed by crews "to achieve the highest possible rates of fire in gunnery competitions."

German warships were better protected. Damage to the battlecruiser Seydlitz four months earlier had alerted German admirals to the danger of turret fire. Their capital ships had antiflash protection, and while Jutland was perhaps a strategic German defeat, the exchange of big ships was three to one in their favor.

The lesson that turrets are a battleship's most vulnerable points has been brought home again to the U.S. Navy in recent months, by the gun explosion on the U.S.S. Iowa that killed 47 men. By peeling back layers of romanticism and dogma to expose what really happens in naval war, Keegan's book shows the roots of many of today's naval problems.

His lesson is that real military preparedness often revolves around mundane items and activities. Attention to turret safety is but one example. Another is the quality of torpedoes. Keegan points out that at the end of World War II even the best torpedoes were comparatively shortlegged and inaccurate. Today some experts complain that U.S. torpedoes can't dive deep enough or move fast enough to catch many Soviet submarines. And as Keegan's chapter on the U-boat battles of the Atlantic amply demonstrates, submarine communication was a major problem in World War II; he says that it "remains an unsolved weakness."

Keegan's strength as an author has always been his grasp of what actually happens in war, as opposed to what movie convention and War Ministry propaganda imply. In his classic, Face of Battle, due for reissue soon in an illustrated edition, he took a series of land battles, beginning with Agincourt, and examined them to determine what men who experienced them must have gone through. The exercise leaves no illusion about the glories of combat, revealing it as a brutal and random business. Indeed, in his conclusion to Face of Battle, Keegan theorized that modern land combat would be so horrible that men would simply refuse to fight.

The Price of Admiralty takes the same approach. Four battles - Trafalgar, Jutland, Midway, and the Battle of the Atlantic - are examined in detail. The result is not so much a portrait of men at war as a study of change and counter-change. In Keegan's book, naval warfare seems a uniquely technology-dependent type of combat, with new generations of machines completely transforming the rules. Status quo means defeat.

At Trafalgar the innovation was tactical. According to Keegan, until this episode sea battles resembled World War I land battles, with opposing fleets prizing position and ignoring maneuver, content to slug it out line against line. Admiral Nelson successfully flouted this conception by sending his ships plunging into holes in the French and Spanish lines.

At Jutland the innovation was battleships. The first and last great confrontation of dreadnoughts, Jutland brought home the fact that technology had accelerated, that navies were vulnerable to defeat "in an afternoon" it found deficient in armor, gunnery, or flash protection. Midway and the Battle of the Atlantic showed how quickly entirely new ways of waging naval war - aircraft carriers, submarines - could rise, threatening the supremacy of nations whose old salts cling to old ways.

And today the U.S. Navy may be clinging to old ways. In the aftermath of World War II, the aircraft carrier came to dominate the U.S. fleet. But Keegan sees subs as the capital ships of the future, for the simple reason that full freedom of the seas, both above and below, rests only with them. By contrast, he judges conventional surface ships as "marginalized" instruments of military force.

Yet the U.S. Navy still clings to the big deck carrier, while, compared to the Soviet Union, the U.S. sub fleet is small. The arguments against carriers are by now op-ed cliches - too much of their strength is spent defending themselves, they're vulnerable to cheap smart missiles, etc., etc. It's notable that Price of Admiralty recycles none of these points. Instead it shows by accretion of historical detail what happens to navies that, faced with a choice in technology, choose wrong.

Unworkable technology has long been the nemesis of efficiency in all military branches. The U.S. Navy might well have turned the tide against the Japanese in the Pacific much earlier if its submarines had not been stocked with torpedoes that misfired at catastrophic rates. Then there's the Army's famous reluctance at the start of the Vietnam war to abandon the heavy and hard-to-control M-14 rifle, and its subsequent perversion of a viable preexisting design of a light, reliable one. Or the Air Force and Navy decision in the sixties to commit to a missile-only fighter even as Vietnam and Middle East experience was showing the necessity of guns in air warfare.

The adaptation of technical advances to weaponry is a touchy business, one that must strike a balance between reliance on horse cavalry and a belief in silver bullets. Lately the silver bullet crowd has had the upper hand. But the ever-increasing expense of weapons technology combined with decreased funding makes choosing correctly all the more important. John Keegan's books show that weapons aren't the only determinant of the outcome in warfare, that training, tactics, and preparedness matter as well. Now that he's written about land warfare, naval battles, and military leadership, perhaps he'll turn to the most puzzling, inscrutable military subject of all - the Pentagon acquisition bureaucracy. Having seen Keegan masterfully evoke Trafalgar, I would like to read his account of a Defense Resources Board meeting.