Trouble is sometimes good in a way; it makes a person resourceful. Tom Swift had had his share of annoyances of late, but they had served a purpose. He had learned to think clearly and quickly. Now, when he found his boat stolen, he at once began to map out a plan of action.

"What will you do first?" asked Mr. Jackson as he saw his employer's son hesitating.

"First I'm going to Andy Foger's house," declared the young inventor. "If he's home I'm going to tell him what I think of him. If he's not, I'm going to find him."

"Why don't you take your sailboat and run down to his dock?" suggested the engineer. "It isn't as quick as your motor-boat, but it's better than walking."

"So it is," exclaimed the lad. "I will use my catboat. I had forgotten all about it of late. I'm glad you spoke."

He was soon sailing down the lake in the direction of the boathouse on the waterfront of Mr. Foger's property. It needed but a glance around the dock to show him that the Red Streak was not there, but Tom recollected the accident to the steering gear and thought perhaps Andy had taken his boat to some wharf where there was a repair shop and there left it to return home himself. But inquiry of Mrs. Foger, who was as nice a woman as her son was a mean lad, gave Tom the information that his enemy was not at home.

"He telephoned to me that his boat was damaged," said Mrs. Foger gently, "and that he had taken it to get fixed. Then, he said, he and some friends were going on a little cruise and might not be back to-night."

"Did he say where he was going?" asked our hero, who did not tell Andy's mother why he wanted to see her son.

"No, and I'm worried about him. Sometimes I think Andy is too--- well, too impetuous, and I'm afraid he will get into trouble."

Tom, in spite of his trouble, could hardly forbear smiling. Andy's mother was totally unaware of the mean traits of her son and thought him a very fine chap. Tom was not going to undeceive her.

"I'm afraid something will happen to him," she went on. "Do you think there is any danger being out on the lake in a motor-boat, Mr. Swift? I understand you have one."

"Yes, I have one," answered Tom. He was going to say he had once had one, but thought better of it. "No, there is very little danger this time of year," he added.

"I am very glad to hear you say so," went on Mrs. Foger with a sigh. "I shall feel more at ease when Andy is away now. When he returns home, I shall tell him you called upon him and he will return your visit. I am glad to see that the custom of paying calls has not died out among the present generation. It is a pleasant habit, and I am glad to have my son conform to it. He shall return your kind visit."

"Oh, no, it's of no consequence," replied Tom quickly, thinking grimly that his visit was far from a friendly one. "There is no need to tell your son I was here. I will probably see him in a day or two.

"Oh, but I shall tell him," insisted Mrs. Foger with a kind smile. "I'm sure he will appreciate your call."

There was much doubt concerning this in the mind of the young inventor, but he did not express it and soon took his leave. Up and down the lake for the rest of the day he cruised, looking in vain for a sight of Andy Foger in the Red Streak, but the racing boat appeared to be well hidden.

"If I only could find where they've taken mine," mused Tom. "Hang it all, this is rotten luck!" and for the first time he began to feel discouraged.

"Maybe you'd better notify the police," suggested Mr. Jackson when Tom returned to the Swift house that night. "They might help locate it."

"I think I can do as well as the police," answered the youth. "If the boat is anywhere it's on the lake, and the police have no craft in which to make a search."

"That's so," agreed the engineer. "I wish I could help you, but I don't believe it would be wise for me to leave the house, especially since those men have been about lately."

"No, you must stay here," was Tom's opinion. "I'll take another day or two to search. By this time Andy and his gang will return, I'm sure, and I can tackle them."

"Suppose they don't?"

"Well, then I'll make a tour of the lake in my sailboat and I'll run up to Sandport and tell dad, for he will wonder what's keeping me. I'll know better next time than to leave my boat at the dock without taking out the connection at the spark coil, so no one can start the motor. I should have done that at first, but you always think of those things afterward."

The lad began his search again the next morning and cruised about in little bays and gulfs looking for a sight of the Red Streak or the Arrow, but he saw neither, and a call at Andy's house showed that the red-haired youth had not returned. Mrs. Foger was quite nervous over her son's continued absence, but Mr. Foger thought it was all right.

Another day passed without any results and the young inventor was getting so nervous, partly with worrying over the loss of his boat and partly on his father's account, that he did not know what to do.

"I can't stand it any longer," he announced to Mrs. Baggert the night of the third day, after a telephone message had been received from Mr. Swift. The inventor wanted to know why his son did not return to the hotel to join him and Ned. "Well, what will you do?" asked the housekeeper.

"If I don't find my boat to-morrow, I'll sail to Sandport, bring home dad and Ned and we three will go all over the lake. My boat must be on it somewhere, but Lake Carlopa is so cut up that it could easily be hidden."

"It's queer that the Foger boy doesn't come home. That makes it look as if he was guilty."

"Oh, I'm sure he took it all right," returned Tom. "All I want is to see him. It certainly is queer that he stays away as long as he does. Sam Snedecker and Pete Bailey are with him, too. But they'll have to return some time."

Tom dreamed that night of finding his boat and that it was a wreck. He awoke, glad to find that the latter part was not true, but wishing that some of his night vision might come to pass during the day.

He started out right after breakfast, and, as usual, headed for the Foger home. He almost disliked to ask Mrs. Foger if her son had yet returned, for Andy's mother was so polite and so anxious to know whether any danger threatened that Tom hardly knew how to answer her. But he was saved that embarrassment on this occasion, for as he was going up the walk from the lake to the residence he met the gardener and from him learned that Andy had not yet come back.

"But his mother had a message from him, I did hear," went on the man. "He's on his way. It seems he had some trouble."

"Trouble. What kind of trouble?" asked Tom.

"I don't rightly know, sir, but," and here the gardener winked his eye, "Master Andy isn't particular what kind of trouble he gets into."

"That's right," agreed our hero, and as he went down again to where he had left his boat he thought: "Nor what kind of trouble he gets other people into. I wish I had hold of him for about five minutes!"

The sailboat swung slowly from the dock and heeled over to the gentle breeze. Hardly knowing what to do, Tom headed for the middle of the lake. He was discouraged and tired of making plans only to have them fail.

As he looked across the stretch of water he saw a boat coming toward him. He shaded his eyes with his hand to see better, and then, with a pair of marine glasses, took an observation. He uttered an exclamation.

"That's the Red Streak as sure as I'm alive!" he cried. "But what's the matter with her? They're rowing!"

The lad headed his boat toward the approaching one. There was no doubt about it. It was Andy Foger's craft, but it was not speeding forward under the power of the motor. Slowly and laborious the occupants were pulling it along, and as it was not meant to be rowed, progress was very slow.

"They've had a breakdown," thought Tom. "Serves 'em right! Now wait till I tackle 'em and find out where my boat is. I've a good notion to have Andy Foger arrested!"

The sailing craft swiftly approached the motorboat. Tom could see the three occupants looking at him, apprehensively as well as curiously, he thought.

"Guess they didn't think I'd keep after 'em," mused the young inventor, and a little later he was beside the Red Streak.

"Well," cried Tom angrily, "it's about time you came back!"

"We've had a breakdown," remarked Andy, and he seemed quite humiliated. He was beginning to find out that he didn't know as much about a motor-boat as he thought he did.

"I've been waiting for you," went on Tom.

"Waiting for us? What for?" asked Sam Snedecker.

"What for? As if you didn't know!" blurted out the owner of the Arrow. "I want my boat, Andy Foger, the one you stole from me and hid! Tell me where it is at once or I'll have you arrested!"

"Your boat!" repeated the bully, and there was no mistaking the surprise in his tones.

"Yes, my boat! Don't try to bluff me like that."

"I'm not trying to bluff you. We've been away, three days and just got back."

"Yes, I know you have. You took my boat with you, too."

"Are you crazy?" demanded Pete Bailey.

"No, but you fellows must have been to think you could take my boat and me not know it," and Tom, filled with wrath, grasped the gunwale of the Red Streak as if he feared it would suddenly shoot away.

"Look here!" burst out Andy, and he spoke sincerely, "we didn't touch your boat. Did we, fellows?"

"No!" exclaimed Sam and Pete at once, and they were very much in earnest.

"We didn't even know it was stolen, did we?" went on Andy.

"No," agreed his chums. Tom looked unconvinced.

"We haven't taken your boat and we can prove it," continued the bully. "I know you and I have had quarrels, but I'm telling you the truth, Tom Swift. I never touched your boat."

There was no mistaking the sincerity of Andy. He was not a skilful deceiver, and Tom, looking into his squint-eyes, which were opened unusually wide, could not but help believing the fellow.

"We haven't seen it since the day we had the collision," added Andy, and his chums confirmed this statement.

"We went off on a little cruise," continued the red-haired bully, "and broke down several times. We had bad luck. Just as we were nearing home something went wrong with the engine again. I never saw such a poor motor. But we never took your boat, Tom Swift, and we can prove it."

Tom was in despair. He had been so sure that Andy was the thief, that to believe otherwise was difficult. Yet he felt that he must. He looked at the disabled motor of the Red Streak and viewed it with the interested and expert eye of a machinist, no matter if the owner of it was his enemy. Then suddenly a brilliant idea came into Tom's head.