The inevitable climax is on it's way.  Curly and Morton have arrived with the bell and the main flotilla ship lowers the two over the side  toward Seaview and the minefield waiting below.  Nelson announces on the intercom that help is on the way--conserve air, he cautions.   Shortly after the bell enters the mine field, it fowls a cable and two mines collide, exploding.  Seaview rocks on the bottom tossing about her tired and scared crew.

Nelson on the phone: Hello, Chip; diving bell, come in!  Salvage barge, can ya--can you hear me?  Phone's dead. Crane: I just checked on the angle -- 31 degrees.  That means the bell can't couple with us. Nelson: It's as simple as that.  We need to right ourselves at least five degrees. But, as Patterson notes, they have no power to do that.  Crane points out that there is one way -- flood a compartment.  Blake overhears in the background as Nelson consults a set of blueprints and announces they need to flood compartment 47 to

A fowled mine detonates. . Nerves on edge - a sudden explosion.

right the sub sufficiently. Kowalski: What for -- the bell's gone.  There's nobody out there.  Nobody alive. Crane: Kowalski, we have to count on that bell being there.  I say we flood 47 now.  Nelson: If we open a seacock at this depth, the water will come in like a battering ram. Patterson:But the watertight doors would be shut, sir.  The water would stay in the compartment. Nelson:Yes, and so would the man who opened the valve.  I can't ask any man to do that. The eavesdropping Blake sets his jaw and heads aft.

Blake advances on compartment 47, pushes his way past Harker, who is on his way to the control room, and locks himself in.  He proceeds to open seacocks which let in water from the outside.  Nelson soon learns from Harker that Blake was seen heading into compartment 47 and puts two and two together.  They all race for the compartment, but are too late, as the sonarman is blasted unconscious by the incoming water.

Blake locks himself in compartment 47.

Nelson and Crane try to stop him.

Seawater Blasts in on the doomed Blake.

The realization of Blake's sacrifice hits both Nelson and Crane.  There may have been question
of his attention span, but surely none remains about his character -- not even in Harker's mind.

Because of Blake's sacrifice, Seaview gets the weight-shift she needs and settles back to an angle which allows Curly to guide the diving bell over the submarine's forward hatch for docking.  The sound of the bell clamping onto the deck above sends a surge of relief rushing through the sub.  And it's all made official when Chip Morton drops through the hatchway and says: Permission to come aboard, Sir?

Permission to come aboard, Sir?

Nelson comes running with a smile of relief and an appreciation of life written all over his face.  Survival is what this chapter has been about.  Morton drops into Seaview's control room with the assurance that oxygen and rescue have come to a ship of seemingly doomed men.  Later, back at the Institute, Crane reports that the men, including Bishop are going to be OK.  Nelson has good news too.  Seaview is going to be raised and put back together.

A beaming smile that says it all.

Crane has news as well.  Evans' wife has given birth, and their new baby is a boy -- named Harriman Evans. 

Thus ends a truly classic episode of Voyage to the Bottom of the Sea.  If the writing, production and tone of the show had remained this high during Voyage's entire run, it would probably be remembered today much more fondly and have a current series of successful films based on it.  Hats off to all the people who made this series as great as it was, at least for a time.  Always entertaining, Voyage would later only occasionally reach the general plateau of quality established in its black and white first season.