For those not blessed with such foreknowledge, there are still ways. Merchant skippers, for example, vastly prefer to ride a grav wave clear through their final hyper translation. Power costs are lower, and riding the wave through the hyper wall reduces both the structural and physiological stresses. Which means raiders often lurk at points where inbound grav waves intersect a star's hyper limit, waiting for prey to amble up to them.
And, if all else fails, there is always the blind chance method. Ships are at their most vulnerable at and shortly after they translate back into normal space. Their base velocities are low, their sensor systems are still sorting out the sudden influx of n-space information, and for at least ten minutes or so, while their hyper generators recycle, they can't even dodge back into hyper and run away if something comes at them. A translation right on the system ecliptic is the norm, if not the inviolable rule, so a patient raider might put his ship into a solar orbit right on the hyper limit, run his power (and emissions) down to minimum levels, and simply wait until some fat and unwary freighter translates within his interception envelope. With no emissions to betray it, something as tiny as a warship is extremely difficult to spot, and many an unfortunate merchant skipper's first intimation of trouble has been the arrival of the leading missile salvo.
But the heavy cruiser PNS Sword and her consorts had no need for such hit-or-miss hunting techniques, Captain Theisman thought. Thanks to ONI's spies, Commodore Reichman knew her prey's exact schedule. In fact, Theisman's tac officer had spotted the five-ship convoy and its escort hours ago as Sword's squadron lay doggo in a handy "bubble" in the local grav wave, letting them pass without being spotted in return before emerging in pursuit.
Theisman didn't like his present mission, partly because he disliked both Commodore Annette Reichman and her proposed tactics. Given his druthers, he would have moved to catch the convoy six light-years further along, when it would have to transition between grav waves under impeller drive. Reichman had decided differently—and stupidly, in his opinion—yet that explained only a part of his dislike. He was also a naval officer, with a naval officers innate instinct to protect merchantmen, and the fact that two of the squadron's targets weren't really freighters at all only made it worse. But he'd been asked to do a lot of things he didn't like in his career, and if he had to do it, he might as well do it right... assuming Reichman would let him.
He stood on Sword's command deck, studying his plot, and frowned silently while he awaited the commodore's next order. The Manties were good, as he could attest from painful personal experience, yet Reichman seemed confident. Possibly more confident than the situation merited. True, the convoy escort consisted of only two light cruisers and a trio of tin-cans, but hyper-space combat wasn't like an n-space engagement. Much of a heavier ship's normal defensive advantage was negated here, and Reichman's unconcern over her squadron's increased vulnerability worried Theisman.
Still, the tactical situation was developing much as the commodore had predicted. With so few ships, the escort commander had opted to sweep ahead of the merchies against the greater danger of a head-on interception while only a single escort watched their rear to cover what should have been the vector of minimum threat. Only Reichman didn't need a head-on intercept. The maximum safe velocity in hyper for any merchantman was barely .5 c. That translated to an effective normal-space velocity of many hundreds of times light-speed, but all that mattered were relative speeds, and their better particle and radiation shielding let Reichman's ships attain a velocity twenty percent greater than that. Which meant that she was currently overtaking the convoy at just under thirty thousand KPS and that the trailing destroyer ought to see them just... about... now.
Lieutenant Commander MacAllister jerked upright in his command chair as threat sources sparkled suddenly in his plot. His destroyer's sensors should have read them sooner, even under the conditions of hyper-space, but the count was tentative, and the identifying data codes shifted and flowed as he watched them. Someone back there had some pretty decent electronic warfare capabilities, and they were using them.
His eyes darted to the vector readouts, and he swallowed a curse. They were barely three hundred million klicks back. At their closing speed, they'd overtake the convoy in under three hours, and there was no way in hell merchantmen could outrun them.
He swore softly, rubbing his palms up and down the chair arms. Whoever was sneaking up on them had to have military-grade shielding to generate that much overtake velocity, so they had to be warships. A fact, he thought grimly, their EW activity had already confirmed. Just as that activity confirmed their hostile intent. But who were they? Were there more of them back there than he could see yet? And how powerful were they?
There was only one way to find out.
"Battle stations," MacAllister told his tactical officer grimly, and alarms began to whoop as he turned to his com officer. "Ruth, get a signal off to Captain Zilwicki. Tell her we have bogies coming up from astern—append Tactical's present data—and that I'm turning for a positive ID."
"Aye, aye, Sir."
"Helm, bring us around one-eight-zero degrees. Maximum deceleration."
"Aye, aye, Sir."
"Manny," MacAllister looked at his astrogator, "I want a turnover that puts us back at our present closure rate at ten light-minutes. We may not be able to fingerprint them from there, but we can sure as hell figure out what size they are.
"Yes, Sir." The astrogator bent over his console just as MacAllister's vacsuited exec appeared on the bridge with the lieutenant commander's skin suit slung over her shoulder. He smiled at her in grim thanks and nodded to the display as he took the suit.
"It seems we're invited to a party, Marge." He started for his minuscule briefing room to change. "Hold the fort while I get suited up."
"The tin-can's coming back at us, Sir," Theisman's tac officer reported, and the captain glanced at Reichman, The commodore didn't even blink. No doubt she'd expected it, just as Theisman had. In fact, he'd expected it sooner, and he felt a dull sense of sympathy for the crew of that ship.
"Well, they see us, Ma'am," he said after a moment. "Any orders?"
"No. I doubt he'll come all the way into range before he gets an accurate read on us, but we can hope. Besides," the commodore smiled without humor, "it's not like the bastards can get away from us, now is it?"
"No, Ma'am," Theisman said softly, "I don't suppose it is."
HMS Hotspur decelerated towards the bogies at over 51 KPS as her Warshawski sails channeled the grav wave's power. Nineteen minutes later, she flipped end for end, accelerating away from them until their overtake speed had dropped once more to thirty thousand KPS at a range of just under a hundred and fifty-eight million kilometers, and Lieutenant Commander MacAllisters face tightened as Hotspur's sensors penetrated their ECM at last.
"Get another message off to the Old Lady, Ruth," he said very quietly. "Tell her we have six Peep heavy cruisers—they look like Scimitars. I estimate they'll enter range of the convoy in—" he glanced back down at his plot "—two hours and thirty-six minutes."