CHAPTER VI
The Deadly Tank
The Sky Wagon droned smoothly through a series of figure eights as Rickand Scotty inspected every inch of Clipper Cay and its surroundingwaters. While Rick flew, Scotty marked off landmarks on the chart of theisland that Dr. Ernst had provided.
"I wish we could spot the wreck of the _Maiden Hand_," Scotty remarked.
"Too deep," Rick said. "We can't see bottom at twenty fathoms even inwater as clear as this."
"I've got everything important marked. What say we land and look overour property?"
"Okay. I'll shoot the beach while you look for coral heads. We don'twant to snag a pontoon."
The boys had already identified their house. It was set at the edge ofthe palms, about fifty yards inland from the beach. It looked fine.There was a small dock to which the _Water Witch_ could be tied up whenthe scientists arrived.
Rick estimated that Tony and Zircon would arrive about sundown, twohours hence. The boys had flown over the _Water Witch_ en route from St.Thomas. Apparently the scientists were enjoying the trip. Zircon hadbeen sprawled in the cockpit while Tony trolled for fish.
"I'm a little surprised there wasn't something wrong with the plane,"Rick observed. He and Scotty had gone over the Sky Wagon from propellerhub to rudder, fearful that the unknown enemy might have sabotaged theplane. But there was no sign of any tampering. However, the inspectionhad taken so long that it was late afternoon before they got away. Itwas significant and perhaps a little ominous that Steve and Jimmy Kellyhad assigned a pair of husky Shore Patrol men with .45-caliber sidearmsto stay with them until the plane actually took off.
"Maybe the two men who came after us were acting without orders," Scottyreplied. "Maybe the real brains of the gang aren't even interested inus."
"I hope that you're right. See any coral heads?"
Although most coral growth was limited to the reef area, outcroppings ofcoral called "heads" had grown up toward the surface in some places.There were none in the stretch of water before the beach house whereRick planned to land.
"The water's clear. Pick your direction. There's not enough wind to makeany difference."
"I'll land parallel to the beach."
Rick turned south down the center of the island. When he had reached theright position he cut the throttle, and the nose of the Sky Wagondropped. He banked tightly, reversing course, until the plane was headednorth a hundred yards out from the beach. He let the plane feel its waytoward the water, then felt the first bump as the pontoons touched. In amoment they were down, and Rick swung the plane to taxi in toward theirnew home.
Scotty was already stripping off his shoes and socks. As the pontoonstouched bottom a few yards from shore, Scotty climbed out. Rick cut thegun while his pal pulled the plane up on the beach.
Rick got out and waited until Scotty slipped his shoes on again, thenthey walked to the cottage.
The door was unlocked. Few people came to Clipper Cay, and locks weren'tconsidered necessary. The boys pushed open the front door and walked in.
There was a large living room and three bedrooms, each with twin beds.In the rear of the cottage was a kitchen with kerosene stove andkerosene refrigerator. A fifty-gallon drum out back provided the fuelsupply, which was piped in through copper tubing. Rick checked the fuel.The tank was full. He read the simple instructions tacked to the wallover the refrigerator, then lighted the burner. There were frozen foodsand soft drinks as well as dairy products among their supplies, packedin dry ice in the _Water Witch's_ food locker; the refrigerator would becold enough for the supplies by the time the boat arrived.
For bathing in fresh water there was an outdoor shower, a shower headrigged to a five-gallon drum and supported on a frame of two-by-fourwooden members. A canvas curtain gave privacy. Other sanitary facilitieswere equally primitive but effective.
Scotty opened the door of a lean-to shed on the rear of the house. "Wecan stow our diving gear in here. There's a bench, too. Looks as thoughthe owner used the place for cleaning fish and stowing his fishingequipment."
They walked around to the front of the house where there was a smallporch. A few wicker chairs were upended against the wall. The boysrighted them and sat down.
"This is the life," Rick observed. "Look at that view."
They looked from the porch down to the sandy beach, past the pier andthe Sky Wagon to water that was almost glassy calm. The water continuedin a smooth stretch for about five hundred yards out to the reef. Lightbreakers foamed along the reef, and beyond, the water was a blue wasteto the horizon. A quarter mile south, a break in the reef marked apassage where boats could enter.
Somewhere, out beyond the reef, was the wreck of the _Maiden Hand_. Inhis mind, Rick planned how they would go about finding it. The firststep was to rig some kind of underwater towing boards. Then he andScotty, equipped with their aqualungs, would be towed behind the _WaterWitch_, scanning the bottom as they went.
He wasn't worried about finding material for the towing boards. Any kindof planks would do, or they could even make a tow board out of a fallenlog, although that would be harder to control.
"Come on," he invited. "Let's walk through the palms. We need a fewplanks, and we might as well get them now."
By the time the scientists approached the pier, the boys had exploredthe central part of the island and had returned to the cottage luggingplanks found in the ruin of a cottage apparently blown down by somelong-past hurricane. They dropped the planks beside the house andhurried to catch the line that Zircon threw, then they warped the _WaterWitch_ in to the dock.
All hands turned to, and in a short time supplies were unloaded andstored, beds were made with linen and blankets loaned by Dr. Ernst, andthe cottage began to take on an inhabited look.
While Tony Briotti began preparations for dinner, the boys carried theiraqualung equipment to the shed at the rear of the cottage and began tocheck it over. Since their lives would depend on proper functioning ofthe equipment, they inspected the regulators carefully, checking thecondition of the neoprene flaps. Once checked, the regulators were hungon nails on the shed walls, out of harm's way.
The next step was to inspect the tanks. Rick had already looked themover, but for the sake of safety the boys did it again. There were sixof them, each of seventy-cubic-feet capacity. There was an advantage tothis particular capacity at the depth where they expected to dive; adiver could work only fifteen minutes at 120 feet without requiringdecompression, and seventy cubic feet of air would last just longenough. Double tanks would have meant the boys would be able to staydown nearly twice as long, but would also have meant the nuisance ofwaiting through the decompression period of about thirteen minutes tenfeet below the surface on the ascent. For this reason, the boys plannedto dive with single tanks, leaving the spares on the surface.
Of course, to get even fifteen minutes of diving at twenty fathoms thetanks had to be filled to capacity. When full, they were under enormousinternal pressure of over two thousand pounds per square inch. The tankshad been filled at Spindrift, but the boys decided to check them again,in case there had been some leakage through the valves during shipment.
Scotty swung one tank upright and prepared to attach the pressure gauge.Rick, inspecting another tank for bumps that might have weakened thetank wall, saw him do it.
For a moment Rick continued his inspection, then what he had seensuddenly registered. He yelled, "Scotty! The valve!"
In that instant, as Scotty attached the pressure gauge, the valve blewout!
The entire valve assembly and the pressure gauge, propelled by thetremendous pressure in the tank, blew straight upward, ripping clear ofScotty's hand and taking a patch of skin along. The ascending assembly,traveling with bullet speed, clipped a lock of hair from his bent head.
_The valve assembly, traveling with bullet speed, barelymissed Scotty's head_]
Scotty yelled, "Run!"
The tank, its air free to escape, writhed and turned, then fell over onits
side. It was like an inflated balloon, turned loose to fly around aroom. Air jetted from it with terrific velocity, so that the tank was,for the period while its air lasted, a true rocket.
It struck the wall of the shed and went through it like paper, smashedinto a stud and caromed slightly, so that its trajectory was alteredenough to drive it directly at Rick. He fell flat and it went over, justgrazing him, then flew into the palm grove. It hit a palm a slantingblow and turned upward, shooting high in the air, clipping off the topof another palm as it went.
As the boys watched, horrified, it climbed straight up. Then, its highpressure nearly exhausted, it turned leisurely and plunged back into thegrove, almost burying itself in the sandy soil.
The boys sat down and stared weakly at each other. For the first time,Rick noted that Scotty's hand was bleeding. He said shakily, "Here, letme look at that."
The scientists rushed out of the house and demanded to know what hadhappened. The tank had blown through its devastating course so fast thatthey had not even had time to get outdoors.
Zircon bandaged Scotty's hand with supplies from the first-aid kit whilethe boys told them what had happened. Tony said, "Very careless, leavinga valve loose like that."
Rick told him positively, "It wasn't left unscrewed, Tony. We always usea wrench on those valves because high pressure is so dangerous. And itwasn't like that yesterday. I checked the tanks when we stowed them onthe boat."
Scotty gestured toward the other tanks. "Better take a look."
Rick did so, and gave a low whistle. The valves had all been loosened.They were in place only by a turn or two of the threads.
"They could have come out any time," he said grimly. "Any rough handlingcould have knocked a valve out. And if it had happened on the boat, thetank would have gone right through the bottom or side. It was just luckScotty and I weren't killed."
Zircon wordlessly found the valve wrench and got to work screwing theassemblies back in place. The others watched silently, until Scottysaid, "Well, at least we're out of St. Thomas. There won't be any moresabotage!"